SQLite 3.48.0.

SQLITE_FCNTL_BUSYHANDLER.
SQLITE_FCNTL_SYNC.
2026-01-12 22:19:14 +00:00 · 2025-01-14 17:33:53 +00:00 · 2025-01-14 17:09:54 +00:00 · 2025-01-14 10:05:54 +00:00 · 2025-01-13 13:45:41 +00:00 · 2025-01-13 12:05:27 +00:00
111 changed files with 1366 additions and 523 deletions
--- a/.github/actions/lfs/action.yml
+++ b/.github/actions/lfs/action.yml
@@ -1,23 +0,0 @@
-name: Git LFS pull
-description: Cached Git LFS pull.
-
-runs:
-  using: "composite"
-  steps:
-    - name: Create LFS file list
-      shell: bash
-      run: git lfs ls-files --long | cut -d ' ' -f1 | sort > .lfs-assets-id
-
-    - name: Restore LFS cache
-      uses: actions/cache@v4
-      with:
-        path: .git/lfs/objects
-        key: lfs-${{ hashFiles('.lfs-assets-id') }}
-        restore-keys: lfs-
-        enableCrossOsArchive: true
-
-    - name: Git LFS pull
-      shell: bash
-      run: |
-        git lfs pull
-        git lfs prune
--- a/.github/workflows/cross.sh
+++ b/.github/workflows/cross.sh
@@ -1,25 +0,0 @@
-#!/usr/bin/env bash
-set -euo pipefail
-
-echo android       ; GOOS=android   GOARCH=amd64 go build .
-echo darwin        ; GOOS=darwin    GOARCH=amd64 go build .
-echo dragonfly     ; GOOS=dragonfly GOARCH=amd64 go build .
-echo freebsd       ; GOOS=freebsd   GOARCH=amd64 go build .
-echo illumos       ; GOOS=illumos   GOARCH=amd64 go build .
-echo ios           ; GOOS=ios       GOARCH=amd64 go build .
-echo linux         ; GOOS=linux     GOARCH=amd64 go build .
-echo netbsd        ; GOOS=netbsd    GOARCH=amd64 go build .
-echo openbsd       ; GOOS=openbsd   GOARCH=amd64 go build .
-echo plan9         ; GOOS=plan9     GOARCH=amd64 go build .
-echo solaris       ; GOOS=solaris   GOARCH=amd64 go build .
-echo windows       ; GOOS=windows   GOARCH=amd64 go build .
-echo aix           ; GOOS=aix       GOARCH=ppc64 go build .
-echo js            ; GOOS=js        GOARCH=wasm  go build .
-echo wasip1        ; GOOS=wasip1    GOARCH=wasm  go build .
-echo linux-flock   ; GOOS=linux     GOARCH=amd64 go build -tags sqlite3_flock .
-echo linux-dotlk   ; GOOS=linux     GOARCH=amd64 go build -tags sqlite3_dotlk .
-echo darwin-flock  ; GOOS=darwin    GOARCH=amd64 go build -tags sqlite3_flock .
-echo darwin-dotlk  ; GOOS=darwin    GOARCH=amd64 go build -tags sqlite3_dotlk .
-echo windows-dotlk ; GOOS=windows   GOARCH=amd64 go build -tags sqlite3_dotlk .
-echo freebsd-dotlk ; GOOS=freebsd   GOARCH=amd64 go build -tags sqlite3_dotlk .
-echo solaris-dotlk ; GOOS=solaris   GOARCH=amd64 go build -tags sqlite3_dotlk .
--- a/.github/workflows/cross.yml
+++ b/.github/workflows/cross.yml
@@ -1,16 +0,0 @@
-name: Cross compile
-
-on:
-  workflow_dispatch:
-
-jobs:
-  build:
-    runs-on: ubuntu-latest
-
-    steps:
-    - uses: actions/checkout@v4
-    - uses: actions/setup-go@v5
-      with: { go-version: stable }
-
-    - name: Build
-      run: .github/workflows/cross.sh
--- a/.github/workflows/repro.sh
+++ b/.github/workflows/repro.sh
@@ -2,14 +2,14 @@
 set -euo pipefail

 if [[ "$OSTYPE" == "linux"* ]]; then
-  WASI_SDK="https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-24/wasi-sdk-24.0-x86_64-linux.tar.gz"
-  BINARYEN="https://github.com/WebAssembly/binaryen/releases/download/version_120/binaryen-version_120-x86_64-linux.tar.gz"
+  WASI_SDK="https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-25/wasi-sdk-25.0-x86_64-linux.tar.gz"
+  BINARYEN="https://github.com/WebAssembly/binaryen/releases/download/version_121/binaryen-version_121-x86_64-linux.tar.gz"
 elif [[ "$OSTYPE" == "darwin"* ]]; then
-  WASI_SDK="https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-24/wasi-sdk-24.0-arm64-macos.tar.gz"
-  BINARYEN="https://github.com/WebAssembly/binaryen/releases/download/version_120/binaryen-version_120-arm64-macos.tar.gz"
+  WASI_SDK="https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-25/wasi-sdk-25.0-arm64-macos.tar.gz"
+  BINARYEN="https://github.com/WebAssembly/binaryen/releases/download/version_121/binaryen-version_121-arm64-macos.tar.gz"
 elif [[ "$OSTYPE" == "msys" || "$OSTYPE" == "cygwin" ]]; then
-  WASI_SDK="https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-24/wasi-sdk-24.0-x86_64-windows.tar.gz"
-  BINARYEN="https://github.com/WebAssembly/binaryen/releases/download/version_120/binaryen-version_120-x86_64-windows.tar.gz"
+  WASI_SDK="https://github.com/WebAssembly/wasi-sdk/releases/download/wasi-sdk-25/wasi-sdk-25.0-x86_64-windows.tar.gz"
+  BINARYEN="https://github.com/WebAssembly/binaryen/releases/download/version_121/binaryen-version_121-x86_64-windows.tar.gz"
 fi

 # Download tools
@@ -27,8 +27,8 @@ embed/build.sh
 embed/bcw2/build.sh

 # Download and build sqlite-createtable-parser
-util/sql3util/parse/download.sh
-util/sql3util/parse/build.sh
+util/sql3util/wasm/download.sh
+util/sql3util/wasm/build.sh

 # Check diffs
 git diff --exit-code
--- a/.github/workflows/repro.yml
+++ b/.github/workflows/repro.yml
@@ -18,8 +18,6 @@ jobs:
    steps:
    - uses: ilammy/msvc-dev-cmd@v1
    - uses: actions/checkout@v4
-    - uses: actions/setup-go@v5
-      with: { go-version: stable }

    - name: Build
      shell: bash
@@ -31,4 +29,4 @@ jobs:
        subject-path: |
          embed/sqlite3.wasm
          embed/bcw2/bcw2.wasm
-          util/sql3util/parse/sql3parse_table.wasm
+          util/sql3util/wasm/sql3parse_table.wasm
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -2,19 +2,17 @@ name: Test

 on:
  push:
-    branches: [ "main" ]
+    branches: [ 'main' ]
    paths:
      - '**.go'
      - '**.mod'
      - '**.wasm'
-      - '**.wasm.bz2'
  pull_request:
-    branches: [ "main" ]
+    branches: [ 'main' ]
    paths:
      - '**.go'
      - '**.mod'
      - '**.wasm'
-      - '**.wasm.bz2'
  workflow_dispatch:

 jobs:
@@ -29,9 +27,6 @@ jobs:
    - uses: actions/setup-go@v5
      with: { go-version: stable }

-    - name: Git LFS pull
-      uses: ./.github/actions/lfs
-
    - name: Format
      run: gofmt -s -w . && git diff --exit-code
      if: matrix.os != 'windows-latest'
@@ -56,7 +51,7 @@ jobs:

    - name: Test BSD locks
      run: go test -v -tags sqlite3_flock ./...
-      if: matrix.os == 'macos-latest'
+      if: matrix.os != 'windows-latest'

    - name: Test dot locks
      run: go test -v -tags sqlite3_dotlk ./...
@@ -66,6 +61,10 @@ jobs:
      shell: bash
      run: gormlite/test.sh

+    - name: Test modules
+      shell: bash
+      run: go test -v ./embed/bcw2/...
+
    - name: Collect coverage
      run: go run github.com/dave/courtney@latest
      if: |
@@ -91,6 +90,14 @@ jobs:
          - name: netbsd
            version: '10.0'
            flags: '-test.v'
+          - name: freebsd
+            arch: arm64
+            version: '14.2'
+            flags: '-test.v -test.short'
+          - name: netbsd
+            arch: arm64
+            version: '10.0'
+            flags: '-test.v -test.short'
          - name: openbsd
            version: '7.6'
            flags: '-test.v -test.short'
@@ -100,12 +107,10 @@ jobs:
    steps:
    - uses: actions/checkout@v4

-    - name: Git LFS pull
-      uses: ./.github/actions/lfs
-
    - name: Build
      env:
        GOOS: ${{ matrix.os.name }}
+        GOARCH: ${{ matrix.os.arch }}
        TESTFLAGS: ${{ matrix.os.flags }}
      run: .github/workflows/build-test.sh

@@ -113,6 +118,7 @@ jobs:
      uses: cross-platform-actions/action@v0.26.0
      with:
        operating_system: ${{ matrix.os.name }}
+        architecture: ${{ matrix.os.arch }}
        version: ${{ matrix.os.version }}
        shell: bash
        run: . ./test.sh
@@ -138,9 +144,6 @@ jobs:
    steps:
    - uses: actions/checkout@v4

-    - name: Git LFS pull
-      uses: ./.github/actions/lfs
-
    - name: Build
      env:
        GOOS: ${{ matrix.os.name }}
@@ -156,6 +159,27 @@ jobs:
        copyback: false
        run: . ./test.sh

+  test-wasip1:
+    runs-on: ubuntu-latest
+    needs: test
+
+    steps:
+    - uses: bytecodealliance/actions/wasmtime/setup@v1
+    - uses: actions/checkout@v4
+    - uses: actions/setup-go@v5
+      with: { go-version: stable }
+
+    - name: Set path
+      run: echo "$(go env GOROOT)/misc/wasm" >> "$GITHUB_PATH"
+
+    - name: Test wasmtime
+      env:
+        GOOS: wasip1
+        GOARCH: wasm
+        GOWASIRUNTIME: wasmtime
+        GOWASIRUNTIMEARGS: '--env CI=true'
+      run: go test -v -short -tags sqlite3_dotlk -skip Example ./...
+
  test-qemu:
    runs-on: ubuntu-latest
    needs: test
@@ -166,9 +190,6 @@ jobs:
    - uses: actions/setup-go@v5
      with: { go-version: stable }

-    - name: Git LFS pull
-      uses: ./.github/actions/lfs
-
    - name: Test 386 (32-bit)
      run: GOARCH=386 go test -v -short ./...

@@ -193,8 +214,5 @@ jobs:
    - uses: actions/setup-go@v5
      with: { go-version: stable }

-    - name: Git LFS pull
-      uses: ./.github/actions/lfs
-
    - name: Test
      run: go test -v ./...
--- a/README.md
+++ b/README.md
@@ -74,9 +74,9 @@ This project aims for [high test coverage](https://github.com/ncruces/go-sqlite3
 It also benefits greatly from [SQLite's](https://sqlite.org/testing.html) and
 [wazero's](https://tetrate.io/blog/introducing-wazero-from-tetrate/#:~:text=Rock%2Dsolid%20test%20approach) thorough testing.

-Every commit is [tested](https://github.com/ncruces/go-sqlite3/wiki/Test-matrix) on
+Every commit is [tested](https://github.com/ncruces/go-sqlite3/wiki/Support-matrix) on
 Linux (amd64/arm64/386/riscv64/ppc64le/s390x), macOS (amd64/arm64),
-Windows (amd64), FreeBSD (amd64), OpenBSD (amd64), NetBSD (amd64),
+Windows (amd64), FreeBSD (amd64/arm64), OpenBSD (amd64), NetBSD (amd64/arm64),
 DragonFly BSD (amd64), illumos (amd64), and Solaris (amd64).

 The Go VFS is tested by running SQLite's
--- a/conn.go
+++ b/conn.go
@@ -4,7 +4,9 @@ import (
 	"context"
 	"fmt"
 	"math"
+	"math/rand"
 	"net/url"
+	"runtime"
 	"strings"
 	"time"

@@ -24,7 +26,6 @@ type Conn struct {
 	interrupt  context.Context
 	pending    *Stmt
 	stmts      []*Stmt
-	timer      *time.Timer
 	busy       func(context.Context, int) bool
 	log        func(xErrorCode, string)
 	collation  func(*Conn, string)
@@ -36,7 +37,9 @@ type Conn struct {
 	rollback   func()
 	arena      arena

-	handle uint32
+	busy1st time.Time
+	busylst time.Time
+	handle  uint32
 }

 // Open calls [OpenFlags] with [OPEN_READWRITE], [OPEN_CREATE] and [OPEN_URI].
@@ -65,7 +68,7 @@ func OpenFlags(filename string, flags OpenFlag) (*Conn, error) {
 	return newConn(context.Background(), filename, flags)
 }

-type connKey struct{}
+type connKey = util.ConnKey

 func newConn(ctx context.Context, filename string, flags OpenFlag) (res *Conn, _ error) {
 	err := ctx.Err()
@@ -373,8 +376,13 @@ func (c *Conn) checkInterrupt(handle uint32) {
 }

 func progressCallback(ctx context.Context, mod api.Module, _ uint32) (interrupt uint32) {
-	if c, ok := ctx.Value(connKey{}).(*Conn); ok && c.interrupt.Err() != nil {
-		interrupt = 1
+	if c, ok := ctx.Value(connKey{}).(*Conn); ok {
+		if c.interrupt.Done() != nil {
+			runtime.Gosched()
+		}
+		if c.interrupt.Err() != nil {
+			interrupt = 1
+		}
 	}
 	return interrupt
 }
@@ -389,38 +397,20 @@ func (c *Conn) BusyTimeout(timeout time.Duration) error {
 }

 func timeoutCallback(ctx context.Context, mod api.Module, count, tmout int32) (retry uint32) {
+	// https://fractaledmind.github.io/2024/04/15/sqlite-on-rails-the-how-and-why-of-optimal-performance/
 	if c, ok := ctx.Value(connKey{}).(*Conn); ok && c.interrupt.Err() == nil {
-		const delays = "\x01\x02\x05\x0a\x0f\x14\x19\x19\x19\x32\x32\x64"
-		const totals = "\x00\x01\x03\x08\x12\x21\x35\x4e\x67\x80\xb2\xe4"
-		const ndelay = int32(len(delays) - 1)
-
-		var delay, prior int32
-		if count <= ndelay {
-			delay = int32(delays[count])
-			prior = int32(totals[count])
-		} else {
-			delay = int32(delays[ndelay])
-			prior = int32(totals[ndelay]) + delay*(count-ndelay)
+		switch {
+		case count == 0:
+			c.busy1st = time.Now()
+		case time.Since(c.busy1st) >= time.Duration(tmout)*time.Millisecond:
+			return 0
 		}
-
-		if delay = min(delay, tmout-prior); delay > 0 {
-			delay := time.Duration(delay) * time.Millisecond
-			if c.interrupt.Done() == nil {
-				time.Sleep(delay)
-				return 1
-			}
-			if c.timer == nil {
-				c.timer = time.NewTimer(delay)
-			} else {
-				c.timer.Reset(delay)
-			}
-			select {
-			case <-c.interrupt.Done():
-				c.timer.Stop()
-			case <-c.timer.C:
-				return 1
-			}
+		if time.Since(c.busylst) < time.Millisecond {
+			const sleepIncrement = 2*1024*1024 - 1 // power of two, ~2ms
+			time.Sleep(time.Duration(rand.Int63() & sleepIncrement))
 		}
+		c.busylst = time.Now()
+		return 1
 	}
 	return 0
 }
--- a/const.go
+++ b/const.go
@@ -166,6 +166,7 @@ const (
 	PREPARE_PERSISTENT PrepareFlag = 0x01
 	PREPARE_NORMALIZE  PrepareFlag = 0x02
 	PREPARE_NO_VTAB    PrepareFlag = 0x04
+	PREPARE_DONT_LOG   PrepareFlag = 0x10
 )

 // FunctionFlag is a flag that can be passed to
@@ -219,6 +220,7 @@ const (
 	DBSTATUS_DEFERRED_FKS        DBStatus = 10
 	DBSTATUS_CACHE_USED_SHARED   DBStatus = 11
 	DBSTATUS_CACHE_SPILL         DBStatus = 12
+	// DBSTATUS_MAX              DBStatus = 12
 )

 // DBConfig are the available database connection configuration options.
--- a/driver/driver.go
+++ b/driver/driver.go
@@ -274,6 +274,7 @@ func (n *connector) Connect(ctx context.Context) (res driver.Conn, err error) {
 //	if err != nil {
 //		log.Fatal(err)
 //	}
+//	defer conn.Close()
 //
 //	err = conn.Raw(func(driverConn any) error {
 //		conn := driverConn.(driver.Conn)
@@ -379,7 +380,7 @@ func (c *conn) PrepareContext(ctx context.Context, query string) (driver.Stmt, e
 	if err != nil {
 		return nil, err
 	}
-	if tail != "" {
+	if notWhitespace(tail) {
 		s.Close()
 		return nil, util.TailErr
 	}
--- a/driver/driver_test.go
+++ b/driver/driver_test.go
@@ -225,8 +225,8 @@ func Test_Prepare(t *testing.T) {
 	}

 	_, err = db.Prepare(`SELECT 1; `)
-	if err.Error() != string(util.TailErr) {
-		t.Error("want tailErr")
+	if err != nil {
+		t.Error(err)
 	}

 	_, err = db.Prepare(`SELECT 1; SELECT`)
--- a/driver/savepoint_test.go
+++ b/driver/savepoint_test.go
@@ -6,6 +6,7 @@ import (

 	"github.com/ncruces/go-sqlite3/driver"
 	_ "github.com/ncruces/go-sqlite3/embed"
+	_ "github.com/ncruces/go-sqlite3/internal/testcfg"
 	_ "github.com/ncruces/go-sqlite3/vfs/memdb"
 )

--- a/driver/time_test.go
+++ b/driver/time_test.go
@@ -27,12 +27,12 @@ func Fuzz_stringOrTime_1(f *testing.F) {
 			// Make sure times round-trip to the same string:
 			// https://pkg.go.dev/database/sql#Rows.Scan
 			if v.Format(time.RFC3339Nano) != str {
-				t.Fatalf("did not round-trip: %q", str)
+				t.Errorf("did not round-trip: %q", str)
 			}
 		} else {
 			date, err := time.Parse(time.RFC3339Nano, str)
 			if err == nil && date.Format(time.RFC3339Nano) == str {
-				t.Fatalf("would round-trip: %q", str)
+				t.Errorf("would round-trip: %q", str)
 			}
 		}
 	})
--- a/driver/util.go
+++ b/driver/util.go
@@ -12,3 +12,63 @@ func namedValues(args []driver.Value) []driver.NamedValue {
 	}
 	return named
 }
+
+func notWhitespace(sql string) bool {
+	const (
+		code = iota
+		slash
+		minus
+		ccomment
+		sqlcomment
+		endcomment
+	)
+
+	state := code
+	for _, b := range ([]byte)(sql) {
+		if b == 0 {
+			break
+		}
+
+		switch state {
+		case code:
+			switch b {
+			case '/':
+				state = slash
+			case '-':
+				state = minus
+			case ' ', ';', '\t', '\n', '\v', '\f', '\r':
+				continue
+			default:
+				return true
+			}
+		case slash:
+			if b != '*' {
+				return true
+			}
+			state = ccomment
+		case minus:
+			if b != '-' {
+				return true
+			}
+			state = sqlcomment
+		case ccomment:
+			if b == '*' {
+				state = endcomment
+			}
+		case sqlcomment:
+			if b == '\n' {
+				state = code
+			}
+		case endcomment:
+			switch b {
+			case '/':
+				state = code
+			case '*':
+				state = endcomment
+			default:
+				state = ccomment
+			}
+		}
+	}
+	return state == slash || state == minus
+}
--- a/driver/util_test.go
+++ b/driver/util_test.go
@@ -1,9 +1,13 @@
 package driver

 import (
+	"context"
 	"database/sql/driver"
 	"reflect"
 	"testing"
+
+	_ "github.com/ncruces/go-sqlite3/embed"
+	_ "github.com/ncruces/go-sqlite3/internal/testcfg"
 )

 func Test_namedValues(t *testing.T) {
@@ -16,3 +20,67 @@ func Test_namedValues(t *testing.T) {
 		t.Errorf("got %v, want %v", got, want)
 	}
 }
+
+func Fuzz_notWhitespace(f *testing.F) {
+	f.Add("")
+	f.Add(" ")
+	f.Add(";")
+	f.Add("0")
+	f.Add("-")
+	f.Add("-0")
+	f.Add("--")
+	f.Add("--0")
+	f.Add("--\n")
+	f.Add("--0\n")
+	f.Add("/0")
+	f.Add("/*")
+	f.Add("/*/")
+	f.Add("/**")
+	f.Add("/*0")
+	f.Add("/**/")
+	f.Add("/***/")
+	f.Add("/**0/")
+	f.Add("\v")
+	f.Add(" \v")
+	f.Add("\xf0")
+	f.Add("\000")
+
+	db, err := Open(":memory:")
+	if err != nil {
+		f.Fatal(err)
+	}
+	defer db.Close()
+
+	f.Fuzz(func(t *testing.T, str string) {
+		if len(str) > 128 {
+			t.SkipNow()
+		}
+
+		c, err := db.Conn(context.Background())
+		if err != nil {
+			t.Fatal(err)
+		}
+		defer c.Close()
+
+		c.Raw(func(driverConn any) error {
+			conn := driverConn.(*conn).Conn
+			stmt, tail, err := conn.Prepare(str)
+			stmt.Close()
+
+			// It's hard to be bug for bug compatible with SQLite.
+			// We settle for somewhat less:
+			//   - if SQLite reports whitespace, we must too
+			//   - if we report whitespace, SQLite must not parse a statement
+			if notWhitespace(str) {
+				if stmt == nil && tail == "" && err == nil {
+					t.Errorf("was whitespace: %q", str)
+				}
+			} else {
+				if stmt != nil {
+					t.Errorf("was not whitespace: %q (%v)", str, err)
+				}
+			}
+			return nil
+		})
+	})
+}
--- a/embed/README.md
+++ b/embed/README.md
@@ -1,6 +1,6 @@
 # Embeddable Wasm build of SQLite

-This folder includes an embeddable Wasm build of SQLite 3.47.2 for use with
+This folder includes an embeddable Wasm build of SQLite 3.48.0 for use with
 [`github.com/ncruces/go-sqlite3`](https://pkg.go.dev/github.com/ncruces/go-sqlite3).

 The following optional features are compiled in:
--- a/embed/bcw2/README.md
+++ b/embed/bcw2/README.md
@@ -1,13 +1,19 @@
 # Embeddable Wasm build of SQLite

-This folder includes an embeddable Wasm build of SQLite, including the experimental
+This folder includes an alternative embeddable Wasm build of SQLite,
+which includes the experimental
 [`BEGIN CONCURRENT`](https://sqlite.org/src/doc/begin-concurrent/doc/begin_concurrent.md) and
 [Wal2](https://sqlite.org/cgi/src/doc/wal2/doc/wal2.md) patches.

+It also enables the optional
+[`UPDATE … ORDER BY … LIMIT`](https://sqlite.org/lang_update.html#optional_limit_and_order_by_clauses) and
+[`DELETE … ORDER BY … LIMIT`](https://sqlite.org/lang_delete.html#optional_limit_and_order_by_clauses) clauses,
+and the [`WITHIN GROUP ORDER BY`](https://sqlite.org/compile.html#enable_ordered_set_aggregates) aggregate syntax.
+
 > [!IMPORTANT]  
 > This package is experimental.
 > It is built from the `bedrock` branch of SQLite,
-> since that is _currently_ the most stable, maintained branch to include both features.
+> since that is _currently_ the most stable, maintained branch to include these features.

 > [!CAUTION]
 > The Wal2 journaling mode creates databases that other versions of SQLite cannot access.
--- a/embed/bcw2/bcw2.wasm
+++ b/embed/bcw2/bcw2.wasm
--- a/embed/bcw2/bcw2_test.go
+++ b/embed/bcw2/bcw2_test.go
@@ -5,6 +5,7 @@ import (
 	"testing"

 	"github.com/ncruces/go-sqlite3/driver"
+	"github.com/ncruces/go-sqlite3/ext/stats"
 	"github.com/ncruces/go-sqlite3/vfs"
 )

@@ -15,7 +16,7 @@ func Test_bcw2(t *testing.T) {

 	tmp := filepath.ToSlash(filepath.Join(t.TempDir(), "test.db"))

-	db, err := driver.Open("file:" + tmp + "?_pragma=journal_mode(wal2)&_txlock=concurrent")
+	db, err := driver.Open("file:"+tmp+"?_pragma=journal_mode(wal2)&_txlock=concurrent", stats.Register)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -32,6 +33,16 @@ func Test_bcw2(t *testing.T) {
 		t.Fatal(err)
 	}

+	_, err = tx.Exec(`DELETE FROM test LIMIT 1`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	_, err = tx.Exec(`SELECT median() WITHIN GROUP (ORDER BY col) FROM test`)
+	if err != nil {
+		t.Fatal(err)
+	}
+
 	err = tx.Commit()
 	if err != nil {
 		t.Fatal(err)
--- a/embed/bcw2/build.sh
+++ b/embed/bcw2/build.sh
@@ -13,15 +13,15 @@ mkdir -p build/ext/
 cp "$ROOT"/sqlite3/*.[ch] build/
 cp "$ROOT"/sqlite3/*.patch build/

-# https://sqlite.org/src/info/08cfa7e8b3090151
-curl -# https://sqlite.org/src/tarball/sqlite.tar.gz?r=08cfa7e8 | tar xz
+# https://sqlite.org/src/info/fab341c829554573
+curl -# https://sqlite.org/src/tarball/sqlite.tar.gz?r=fab341c8 | tar xz

 cd sqlite
 if [[ "$OSTYPE" == "msys" || "$OSTYPE" == "cygwin" ]]; then
-	MSYS_NO_PATHCONV=1 nmake /f makefile.msc sqlite3.c
+	MSYS_NO_PATHCONV=1 nmake /f makefile.msc sqlite3.c "OPTS=-DSQLITE_ENABLE_UPDATE_DELETE_LIMIT -DSQLITE_ENABLE_ORDERED_SET_AGGREGATES"
 else
-	sh configure
-	make sqlite3.c
+	sh configure --enable-update-limit
+	OPTS=-DSQLITE_ENABLE_ORDERED_SET_AGGREGATES make sqlite3.c
 fi
 cd ~-

@@ -38,7 +38,7 @@ mv sqlite/ext/misc/spellfix.c   build/ext/
 mv sqlite/ext/misc/uint.c       build/ext/

 cd build
-cat *.patch | patch --no-backup-if-mismatch
+cat *.patch | patch -p0 --no-backup-if-mismatch
 cd ~-

 "$WASI_SDK/clang" --target=wasm32-wasi -std=c23 -g0 -O2 \
@@ -46,7 +46,7 @@ cd ~-
 	-o bcw2.wasm "build/main.c" \
 	-I"build" \
 	-mexec-model=reactor \
-	-matomics -msimd128 -mmutable-globals -mmultivalue \
+	-msimd128 -mmutable-globals -mmultivalue \
 	-mbulk-memory -mreference-types \
 	-mnontrapping-fptoint -msign-ext \
 	-fno-stack-protector -fno-stack-clash-protection \
@@ -54,6 +54,7 @@ cd ~-
 	-Wl,--import-undefined \
 	-Wl,--initial-memory=327680 \
 	-D_HAVE_SQLITE_CONFIG_H \
+	-DSQLITE_ENABLE_UPDATE_DELETE_LIMIT \
 	-DSQLITE_CUSTOM_INCLUDE=sqlite_opt.h \
 	$(awk '{print "-Wl,--export="$0}' ../exports.txt)

--- a/embed/bcw2/go.mod
+++ b/embed/bcw2/go.mod
@@ -4,10 +4,11 @@ go 1.21

 toolchain go1.23.0

-require github.com/ncruces/go-sqlite3 v0.21.0
+require github.com/ncruces/go-sqlite3 v0.21.3

 require (
 	github.com/ncruces/julianday v1.0.0 // indirect
+	github.com/ncruces/sort v0.1.2 // indirect
 	github.com/tetratelabs/wazero v1.8.2 // indirect
-	golang.org/x/sys v0.28.0 // indirect
+	golang.org/x/sys v0.29.0 // indirect
 )
--- a/embed/bcw2/go.sum
+++ b/embed/bcw2/go.sum
@@ -1,10 +1,12 @@
-github.com/ncruces/go-sqlite3 v0.21.0 h1:EwKFoy1hHEopN4sFZarmi+McXdbCcbTuLixhEayXVbQ=
-github.com/ncruces/go-sqlite3 v0.21.0/go.mod h1:zxMOaSG5kFYVFK4xQa0pdwIszqxqJ0W0BxBgwdrNjuA=
+github.com/ncruces/go-sqlite3 v0.21.3 h1:hHkfNQLcbnxPJZhC/RGw9SwP3bfkv/Y0xUHWsr1CdMQ=
+github.com/ncruces/go-sqlite3 v0.21.3/go.mod h1:zxMOaSG5kFYVFK4xQa0pdwIszqxqJ0W0BxBgwdrNjuA=
 github.com/ncruces/julianday v1.0.0 h1:fH0OKwa7NWvniGQtxdJRxAgkBMolni2BjDHaWTxqt7M=
 github.com/ncruces/julianday v1.0.0/go.mod h1:Dusn2KvZrrovOMJuOt0TNXL6tB7U2E8kvza5fFc9G7g=
+github.com/ncruces/sort v0.1.2 h1:zKQ9CA4fpHPF6xsUhRTfi5EEryspuBpe/QA4VWQOV1U=
+github.com/ncruces/sort v0.1.2/go.mod h1:vEJUTBJtebIuCMmXD18GKo5GJGhsay+xZFOoBEIXFmE=
 github.com/tetratelabs/wazero v1.8.2 h1:yIgLR/b2bN31bjxwXHD8a3d+BogigR952csSDdLYEv4=
 github.com/tetratelabs/wazero v1.8.2/go.mod h1:yAI0XTsMBhREkM/YDAK/zNou3GoiAce1P6+rp/wQhjs=
-golang.org/x/sys v0.28.0 h1:Fksou7UEQUWlKvIdsqzJmUmCX3cZuD2+P3XyyzwMhlA=
-golang.org/x/sys v0.28.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.29.0 h1:TPYlXGxvx1MGTn2GiZDhnjPA9wZzZeGKHHmKhHYvgaU=
+golang.org/x/sys v0.29.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/text v0.21.0 h1:zyQAAkrwaneQ066sspRyJaG9VNi/YJ1NfzcGB3hZ/qo=
 golang.org/x/text v0.21.0/go.mod h1:4IBbMaMmOPCJ8SecivzSH54+73PCFmPWxNTLm+vZkEQ=
--- a/embed/bcw2/init.go
+++ b/embed/bcw2/init.go
@@ -11,13 +11,14 @@ package bcw2

 import (
 	_ "embed"
+	"unsafe"

 	"github.com/ncruces/go-sqlite3"
 )

 //go:embed bcw2.wasm
-var binary []byte
+var binary string

 func init() {
-	sqlite3.Binary = binary
+	sqlite3.Binary = unsafe.Slice(unsafe.StringData(binary), len(binary))
 }
--- a/embed/build.sh
+++ b/embed/build.sh
@@ -14,7 +14,7 @@ trap 'rm -f sqlite3.tmp' EXIT
 	-o sqlite3.wasm "$ROOT/sqlite3/main.c" \
 	-I"$ROOT/sqlite3" \
 	-mexec-model=reactor \
-	-matomics -msimd128 -mmutable-globals -mmultivalue \
+	-msimd128 -mmutable-globals -mmultivalue \
 	-mbulk-memory -mreference-types \
 	-mnontrapping-fptoint -msign-ext \
 	-fno-stack-protector -fno-stack-clash-protection \
--- a/embed/exports.txt
+++ b/embed/exports.txt
@@ -77,6 +77,7 @@ sqlite3_get_autocommit
 sqlite3_get_auxdata
 sqlite3_hard_heap_limit64
 sqlite3_interrupt
+sqlite3_invoke_busy_handler_go
 sqlite3_last_insert_rowid
 sqlite3_limit
 sqlite3_malloc64
--- a/embed/init.go
+++ b/embed/init.go
@@ -8,13 +8,14 @@ package embed

 import (
 	_ "embed"
+	"unsafe"

 	"github.com/ncruces/go-sqlite3"
 )

 //go:embed sqlite3.wasm
-var binary []byte
+var binary string

 func init() {
-	sqlite3.Binary = binary
+	sqlite3.Binary = unsafe.Slice(unsafe.StringData(binary), len(binary))
 }
--- a/embed/init_test.go
+++ b/embed/init_test.go
@@ -19,7 +19,7 @@ func Test_init(t *testing.T) {
 	if err != nil {
 		t.Fatal(err)
 	}
-	if version != "3.47.2" {
+	if version != "3.48.0" {
 		t.Error(version)
 	}
 }
--- a/embed/sqlite3.wasm
+++ b/embed/sqlite3.wasm
--- a/ext/blobio/blob.go
+++ b/ext/blobio/blob.go
@@ -44,6 +44,8 @@ func Register(db *sqlite3.Conn) error {
 type OpenCallback func(*sqlite3.Blob, ...sqlite3.Value) error

 func readblob(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	_ = arg[5] // bounds check
+
 	blob, err := getAuxBlob(ctx, arg, false)
 	if err != nil {
 		ctx.ResultError(err)
@@ -78,6 +80,8 @@ func readblob(ctx sqlite3.Context, arg ...sqlite3.Value) {
 }

 func writeblob(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	_ = arg[5] // bounds check
+
 	blob, err := getAuxBlob(ctx, arg, true)
 	if err != nil {
 		ctx.ResultError(err)
--- a/ext/closure/closure.go
+++ b/ext/closure/closure.go
@@ -84,10 +84,11 @@ func (c *closure) BestIndex(idx *sqlite3.IndexInfo) error {
 	cost := 1e7

 	for i, cst := range idx.Constraint {
-		if !cst.Usable {
+		switch {
+		case !cst.Usable:
 			continue
-		}
-		if plan&1 == 0 && cst.Column == _COL_ROOT {
+
+		case plan&1 == 0 && cst.Column == _COL_ROOT:
 			switch cst.Op {
 			case sqlite3.INDEX_CONSTRAINT_EQ:
 				plan |= 1
@@ -97,9 +98,8 @@ func (c *closure) BestIndex(idx *sqlite3.IndexInfo) error {
 					Omit:      true,
 				}
 			}
-			continue
-		}
-		if plan&0xf0 == 0 && cst.Column == _COL_DEPTH {
+
+		case plan&0xf0 == 0 && cst.Column == _COL_DEPTH:
 			switch cst.Op {
 			case sqlite3.INDEX_CONSTRAINT_LT, sqlite3.INDEX_CONSTRAINT_LE, sqlite3.INDEX_CONSTRAINT_EQ:
 				plan |= posi << 4
@@ -110,9 +110,8 @@ func (c *closure) BestIndex(idx *sqlite3.IndexInfo) error {
 					plan |= 2
 				}
 			}
-			continue
-		}
-		if plan&0xf00 == 0 && cst.Column == _COL_TABLENAME {
+
+		case plan&0xf00 == 0 && cst.Column == _COL_TABLENAME:
 			switch cst.Op {
 			case sqlite3.INDEX_CONSTRAINT_EQ:
 				plan |= posi << 8
@@ -123,9 +122,8 @@ func (c *closure) BestIndex(idx *sqlite3.IndexInfo) error {
 					Omit:      true,
 				}
 			}
-			continue
-		}
-		if plan&0xf000 == 0 && cst.Column == _COL_IDCOLUMN {
+
+		case plan&0xf000 == 0 && cst.Column == _COL_IDCOLUMN:
 			switch cst.Op {
 			case sqlite3.INDEX_CONSTRAINT_EQ:
 				plan |= posi << 12
@@ -135,9 +133,8 @@ func (c *closure) BestIndex(idx *sqlite3.IndexInfo) error {
 					Omit:      true,
 				}
 			}
-			continue
-		}
-		if plan&0xf0000 == 0 && cst.Column == _COL_PARENTCOLUMN {
+
+		case plan&0xf0000 == 0 && cst.Column == _COL_PARENTCOLUMN:
 			switch cst.Op {
 			case sqlite3.INDEX_CONSTRAINT_EQ:
 				plan |= posi << 16
@@ -147,7 +144,6 @@ func (c *closure) BestIndex(idx *sqlite3.IndexInfo) error {
 					Omit:      true,
 				}
 			}
-			continue
 		}
 	}

--- a/ext/lines/lines.go
+++ b/ext/lines/lines.go
@@ -38,7 +38,7 @@ func RegisterFS(db *sqlite3.Conn, fsys fs.FS) error {
 	return errors.Join(
 		sqlite3.CreateModule(db, "lines", nil,
 			func(db *sqlite3.Conn, _, _, _ string, _ ...string) (lines, error) {
-				err := db.DeclareVTab(`CREATE TABLE x(line TEXT, data HIDDEN)`)
+				err := db.DeclareVTab(`CREATE TABLE x(line TEXT, data HIDDEN, delim HIDDEN)`)
 				if err == nil {
 					err = db.VTabConfig(sqlite3.VTAB_INNOCUOUS)
 				}
@@ -46,7 +46,7 @@ func RegisterFS(db *sqlite3.Conn, fsys fs.FS) error {
 			}),
 		sqlite3.CreateModule(db, "lines_read", nil,
 			func(db *sqlite3.Conn, _, _, _ string, _ ...string) (lines, error) {
-				err := db.DeclareVTab(`CREATE TABLE x(line TEXT, data HIDDEN)`)
+				err := db.DeclareVTab(`CREATE TABLE x(line TEXT, data HIDDEN, delim HIDDEN)`)
 				if err == nil {
 					err = db.VTabConfig(sqlite3.VTAB_DIRECTONLY)
 				}
@@ -58,19 +58,29 @@ type lines struct {
 	fsys fs.FS
 }

-func (l lines) BestIndex(idx *sqlite3.IndexInfo) error {
+func (l lines) BestIndex(idx *sqlite3.IndexInfo) (err error) {
+	err = sqlite3.CONSTRAINT
 	for i, cst := range idx.Constraint {
-		if cst.Column == 1 && cst.Op == sqlite3.INDEX_CONSTRAINT_EQ && cst.Usable {
+		if !cst.Usable || cst.Op != sqlite3.INDEX_CONSTRAINT_EQ {
+			continue
+		}
+		switch cst.Column {
+		case 1:
 			idx.ConstraintUsage[i] = sqlite3.IndexConstraintUsage{
 				Omit:      true,
 				ArgvIndex: 1,
 			}
 			idx.EstimatedCost = 1e6
 			idx.EstimatedRows = 100
-			return nil
+			err = nil
+		case 2:
+			idx.ConstraintUsage[i] = sqlite3.IndexConstraintUsage{
+				Omit:      true,
+				ArgvIndex: 2,
+			}
 		}
 	}
-	return sqlite3.CONSTRAINT
+	return err
 }

 func (l lines) Open() (sqlite3.VTabCursor, error) {
@@ -85,6 +95,7 @@ type cursor struct {
 	line  []byte
 	rowID int64
 	eof   bool
+	delim byte
 }

 func (c *cursor) EOF() bool {
@@ -140,6 +151,15 @@ func (c *reader) Filter(idxNum int, idxStr string, arg ...sqlite3.Value) error {
 		return fmt.Errorf("lines: unsupported argument:%.0w %v", sqlite3.MISMATCH, typ)
 	}

+	c.delim = '\n'
+	if len(arg) > 1 {
+		b := arg[1].RawText()
+		if len(b) != 1 {
+			return fmt.Errorf("lines: delimiter must be a single byte%.0w", sqlite3.MISMATCH)
+		}
+		c.delim = b[0]
+	}
+
 	c.reader = bufio.NewReader(r)
 	c.closer, _ = r.(io.Closer)
 	c.rowID = 0
@@ -150,7 +170,12 @@ func (c *reader) Next() (err error) {
 	c.line = c.line[:0]
 	for more := true; more; {
 		var line []byte
-		line, more, err = c.reader.ReadLine()
+		if c.delim == '\n' {
+			line, more, err = c.reader.ReadLine()
+		} else {
+			line, err = c.reader.ReadSlice(c.delim)
+			more = err == bufio.ErrBufferFull
+		}
 		c.line = append(c.line, line...)
 	}
 	if err == io.EOF {
@@ -177,18 +202,27 @@ func (c *buffer) Filter(idxNum int, idxStr string, arg ...sqlite3.Value) error {
 		return fmt.Errorf("lines: unsupported argument:%.0w %v", sqlite3.MISMATCH, typ)
 	}

+	c.delim = '\n'
+	if len(arg) > 1 {
+		b := arg[1].RawText()
+		if len(b) != 1 {
+			return fmt.Errorf("lines: delimiter must be a single byte%.0w", sqlite3.MISMATCH)
+		}
+		c.delim = b[0]
+	}
+
 	c.rowID = 0
 	return c.Next()
 }

 func (c *buffer) Next() error {
-	i := bytes.IndexByte(c.data, '\n')
+	i := bytes.IndexByte(c.data, c.delim)
 	j := i + 1
 	switch {
 	case i < 0:
 		i = len(c.data)
 		j = i
-	case i > 0 && c.data[i-1] == '\r':
+	case i > 0 && c.delim == '\n' && c.data[i-1] == '\r':
 		i--
 	}
 	c.eof = len(c.data) == 0
--- a/ext/lines/lines_test.go
+++ b/ext/lines/lines_test.go
@@ -163,7 +163,7 @@ func Test_lines_test(t *testing.T) {
 	}
 	defer db.Close()

-	rows, err := db.Query(`SELECT rowid, line FROM lines_read(?)`, "lines_test.go")
+	rows, err := db.Query(`SELECT rowid, line FROM lines_read(?, '}')`, "lines_test.go")
 	if errors.Is(err, os.ErrNotExist) {
 		t.Skip(err)
 	}
--- a/ext/regexp/regexp.go
+++ b/ext/regexp/regexp.go
@@ -76,6 +76,7 @@ func load(ctx sqlite3.Context, i int, expr string) (*regexp.Regexp, error) {
 }

 func regex(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	_ = arg[1] // bounds check
 	re, err := load(ctx, 0, arg[0].Text())
 	if err != nil {
 		ctx.ResultError(err)
@@ -165,6 +166,8 @@ func regexInstr(ctx sqlite3.Context, arg ...sqlite3.Value) {
 }

 func regexReplace(ctx sqlite3.Context, arg ...sqlite3.Value) {
+	_ = arg[2] // bounds check
+
 	re, err := load(ctx, 1, arg[1].Text())
 	if err != nil {
 		ctx.ResultError(err)
--- a/ext/serdes/serdes.go
+++ b/ext/serdes/serdes.go
@@ -0,0 +1,136 @@
+// Package serdes provides functions to (de)serialize databases.
+package serdes
+
+import (
+	"io"
+
+	"github.com/ncruces/go-sqlite3"
+	"github.com/ncruces/go-sqlite3/vfs"
+)
+
+func init() {
+	vfs.Register(vfsName, sliceVFS{})
+}
+
+// Serialize backs up a database into a byte slice.
+//
+// https://sqlite.org/c3ref/serialize.html
+func Serialize(db *sqlite3.Conn, schema string) ([]byte, error) {
+	var file sliceFile
+	fileToOpen <- &file
+	err := db.Backup(schema, "file:db?vfs="+vfsName)
+	return file.data, err
+}
+
+// Deserialize restores a database from a byte slice,
+// DESTROYING any contents previously stored in schema.
+//
+// To non-destructively open a database from a byte slice,
+// consider alternatives like the ["reader"] or ["memdb"] VFSes.
+//
+// This differs from the similarly named SQLite API
+// in that it DOES NOT disconnect from schema
+// to reopen as an in-memory database.
+//
+// https://sqlite.org/c3ref/deserialize.html
+//
+// ["memdb"]: https://pkg.go.dev/github.com/ncruces/go-sqlite3/vfs/memdb
+// ["reader"]: https://pkg.go.dev/github.com/ncruces/go-sqlite3/vfs/readervfs
+func Deserialize(db *sqlite3.Conn, schema string, data []byte) error {
+	fileToOpen <- &sliceFile{data}
+	return db.Restore(schema, "file:db?vfs="+vfsName)
+}
+
+var fileToOpen = make(chan *sliceFile, 1)
+
+const vfsName = "github.com/ncruces/go-sqlite3/ext/deserialize.sliceVFS"
+
+type sliceVFS struct{}
+
+func (sliceVFS) Open(name string, flags vfs.OpenFlag) (vfs.File, vfs.OpenFlag, error) {
+	if flags&vfs.OPEN_MAIN_DB == 0 {
+		// notest // OPEN_MEMORY
+		return nil, flags, sqlite3.CANTOPEN
+	}
+	return <-fileToOpen, flags | vfs.OPEN_MEMORY, nil
+}
+
+func (sliceVFS) Delete(name string, dirSync bool) error {
+	// notest // OPEN_MEMORY
+	return sqlite3.IOERR_DELETE
+}
+
+func (sliceVFS) Access(name string, flag vfs.AccessFlag) (bool, error) {
+	return name == "db", nil
+}
+
+func (sliceVFS) FullPathname(name string) (string, error) {
+	return name, nil
+}
+
+type sliceFile struct{ data []byte }
+
+func (f *sliceFile) ReadAt(b []byte, off int64) (n int, err error) {
+	if d := f.data; off < int64(len(d)) {
+		n = copy(b, d[off:])
+	}
+	if n == 0 {
+		err = io.EOF
+	}
+	return
+}
+
+func (f *sliceFile) WriteAt(b []byte, off int64) (n int, err error) {
+	if d := f.data; off > int64(len(d)) {
+		f.data = append(d, make([]byte, off-int64(len(d)))...)
+	}
+	d := append(f.data[:off], b...)
+	if len(d) > len(f.data) {
+		f.data = d
+	}
+	return len(b), nil
+}
+
+func (f *sliceFile) Size() (int64, error) {
+	return int64(len(f.data)), nil
+}
+
+func (f *sliceFile) Truncate(size int64) error {
+	if d := f.data; size < int64(len(d)) {
+		f.data = d[:size]
+	}
+	return nil
+}
+
+func (f *sliceFile) SizeHint(size int64) error {
+	if d := f.data; size > int64(len(d)) {
+		f.data = append(d, make([]byte, size-int64(len(d)))...)
+	}
+	return nil
+}
+
+func (*sliceFile) Close() error { return nil }
+
+func (*sliceFile) Sync(flag vfs.SyncFlag) error { return nil }
+
+func (*sliceFile) Lock(lock vfs.LockLevel) error { return nil }
+
+func (*sliceFile) Unlock(lock vfs.LockLevel) error { return nil }
+
+func (*sliceFile) CheckReservedLock() (bool, error) {
+	// notest // OPEN_MEMORY
+	return false, nil
+}
+
+func (*sliceFile) SectorSize() int {
+	// notest // IOCAP_POWERSAFE_OVERWRITE
+	return 0
+}
+
+func (*sliceFile) DeviceCharacteristics() vfs.DeviceCharacteristic {
+	return vfs.IOCAP_ATOMIC |
+		vfs.IOCAP_SAFE_APPEND |
+		vfs.IOCAP_SEQUENTIAL |
+		vfs.IOCAP_POWERSAFE_OVERWRITE |
+		vfs.IOCAP_SUBPAGE_READ
+}
--- a/ext/serdes/serdes_test.go
+++ b/ext/serdes/serdes_test.go
@@ -0,0 +1,68 @@
+package serdes_test
+
+import (
+	"io"
+	"net/http"
+	"testing"
+
+	"github.com/ncruces/go-sqlite3"
+	_ "github.com/ncruces/go-sqlite3/embed"
+	"github.com/ncruces/go-sqlite3/ext/serdes"
+)
+
+func TestDeserialize(t *testing.T) {
+	if testing.Short() {
+		t.Skip("skipping in short mode")
+	}
+
+	input, err := httpGet()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	db, err := sqlite3.Open(":memory:")
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer db.Close()
+
+	err = serdes.Deserialize(db, "temp", input)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	output, err := serdes.Serialize(db, "temp")
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if len(input) != len(output) {
+		t.Fatal("lengths are different")
+	}
+	for i := range input {
+		// These may be different.
+		switch {
+		case 24 <= i && i < 28:
+			// File change counter.
+			continue
+		case 40 <= i && i < 44:
+			// Schema cookie.
+			continue
+		case 92 <= i && i < 100:
+			// SQLite version that wrote the file.
+			continue
+		}
+		if input[i] != output[i] {
+			t.Errorf("difference at %d: %d %d", i, input[i], output[i])
+		}
+	}
+}
+
+func httpGet() ([]byte, error) {
+	res, err := http.Get("https://raw.githubusercontent.com/jpwhite3/northwind-SQLite3/refs/heads/main/dist/northwind.db")
+	if err != nil {
+		return nil, err
+	}
+	defer res.Body.Close()
+	return io.ReadAll(res.Body)
+}
--- a/ext/unicode/unicode.go
+++ b/ext/unicode/unicode.go
@@ -189,6 +189,7 @@ func like(ctx sqlite3.Context, arg ...sqlite3.Value) {
 			return
 		}
 	}
+	_ = arg[1] // bounds check

 	type likeData struct {
 		*regexp.Regexp
--- a/go.mod
+++ b/go.mod
@@ -8,8 +8,8 @@ require (
 	github.com/ncruces/julianday v1.0.0
 	github.com/ncruces/sort v0.1.2
 	github.com/tetratelabs/wazero v1.8.2
-	golang.org/x/crypto v0.31.0
-	golang.org/x/sys v0.28.0
+	golang.org/x/crypto v0.32.0
+	golang.org/x/sys v0.29.0
 )

 require (
--- a/go.sum
+++ b/go.sum
@@ -10,12 +10,12 @@ github.com/psanford/httpreadat v0.1.0 h1:VleW1HS2zO7/4c7c7zNl33fO6oYACSagjJIyMIw
 github.com/psanford/httpreadat v0.1.0/go.mod h1:Zg7P+TlBm3bYbyHTKv/EdtSJZn3qwbPwpfZ/I9GKCRE=
 github.com/tetratelabs/wazero v1.8.2 h1:yIgLR/b2bN31bjxwXHD8a3d+BogigR952csSDdLYEv4=
 github.com/tetratelabs/wazero v1.8.2/go.mod h1:yAI0XTsMBhREkM/YDAK/zNou3GoiAce1P6+rp/wQhjs=
-golang.org/x/crypto v0.31.0 h1:ihbySMvVjLAeSH1IbfcRTkD/iNscyz8rGzjF/E5hV6U=
-golang.org/x/crypto v0.31.0/go.mod h1:kDsLvtWBEx7MV9tJOj9bnXsPbxwJQ6csT/x4KIN4Ssk=
+golang.org/x/crypto v0.32.0 h1:euUpcYgM8WcP71gNpTqQCn6rC2t6ULUPiOzfWaXVVfc=
+golang.org/x/crypto v0.32.0/go.mod h1:ZnnJkOaASj8g0AjIduWNlq2NRxL0PlBrbKVyZ6V/Ugc=
 golang.org/x/sync v0.10.0 h1:3NQrjDixjgGwUOCaF8w2+VYHv0Ve/vGYSbdkTa98gmQ=
 golang.org/x/sync v0.10.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
-golang.org/x/sys v0.28.0 h1:Fksou7UEQUWlKvIdsqzJmUmCX3cZuD2+P3XyyzwMhlA=
-golang.org/x/sys v0.28.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.29.0 h1:TPYlXGxvx1MGTn2GiZDhnjPA9wZzZeGKHHmKhHYvgaU=
+golang.org/x/sys v0.29.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/text v0.21.0 h1:zyQAAkrwaneQ066sspRyJaG9VNi/YJ1NfzcGB3hZ/qo=
 golang.org/x/text v0.21.0/go.mod h1:4IBbMaMmOPCJ8SecivzSH54+73PCFmPWxNTLm+vZkEQ=
 lukechampine.com/adiantum v1.1.1 h1:4fp6gTxWCqpEbLy40ExiYDDED3oUNWx5cTqBCtPdZqA=
--- a/go.work.sum
+++ b/go.work.sum
@@ -12,5 +12,6 @@ golang.org/x/term v0.24.0/go.mod h1:lOBK/LVxemqiMij05LGJ0tzNr8xlmwBRJ81PX6wVLH8=
 golang.org/x/term v0.25.0/go.mod h1:RPyXicDX+6vLxogjjRxjgD2TKtmAO6NZBsBRfrOLu7M=
 golang.org/x/term v0.26.0/go.mod h1:Si5m1o57C5nBNQo5z1iq+XDijt21BDBDp2bK0QI8e3E=
 golang.org/x/term v0.27.0/go.mod h1:iMsnZpn0cago0GOrHO2+Y7u7JPn5AylBrcoWkElMTSM=
+golang.org/x/term v0.28.0/go.mod h1:Sw/lC2IAUZ92udQNf3WodGtn4k/XoLyZoh8v/8uiwek=
 golang.org/x/tools v0.6.0/go.mod h1:Xwgl3UAJ/d3gWutnCtw505GrjyAbvKui8lOU390QaIU=
 golang.org/x/tools v0.21.1-0.20240508182429-e35e4ccd0d2d/go.mod h1:aiJjzUbINMkxbQROHiO6hDPo2LHcIPhhQsa9DLh0yGk=
--- a/gormlite/ddlmod.go
+++ b/gormlite/ddlmod.go
@@ -17,23 +17,11 @@ var (
 	indexRegexp        = regexp.MustCompile(fmt.Sprintf(`(?is)CREATE(?: UNIQUE)? INDEX [%v]?[\w\d-]+[%v]?(?s:.*?)ON (.*)$`, sqliteSeparator, sqliteSeparator))
 	tableRegexp        = regexp.MustCompile(fmt.Sprintf(`(?is)(CREATE TABLE [%v]?[\w\d-]+[%v]?)(?:\s*\((.*)\))?`, sqliteSeparator, sqliteSeparator))
 	separatorRegexp    = regexp.MustCompile(fmt.Sprintf("[%v]", sqliteSeparator))
-	columnsRegexp      = regexp.MustCompile(fmt.Sprintf(`[(,][%v]?(\w+)[%v]?`, sqliteSeparator, sqliteSeparator))
 	columnRegexp       = regexp.MustCompile(fmt.Sprintf(`^[%v]?([\w\d]+)[%v]?\s+([\w\(\)\d]+)(.*)$`, sqliteSeparator, sqliteSeparator))
 	defaultValueRegexp = regexp.MustCompile(`(?i) DEFAULT \(?(.+)?\)?( |COLLATE|GENERATED|$)`)
 	regRealDataType    = regexp.MustCompile(`[^\d](\d+)[^\d]?`)
 )

-func getAllColumns(s string) []string {
-	allMatches := columnsRegexp.FindAllStringSubmatch(s, -1)
-	columns := make([]string, 0, len(allMatches))
-	for _, matches := range allMatches {
-		if len(matches) > 1 {
-			columns = append(columns, matches[1])
-		}
-	}
-	return columns
-}
-
 type ddl struct {
 	head    string
 	fields  []string
@@ -110,9 +98,10 @@ func parseDDL(strs ...string) (*ddl, error) {
 				if strings.HasPrefix(fUpper, "CONSTRAINT") {
 					matches := uniqueRegexp.FindStringSubmatch(f)
 					if len(matches) > 0 {
-						if columns := getAllColumns(matches[1]); len(columns) == 1 {
+						cols, err := parseAllColumns(matches[1])
+						if err == nil && len(cols) == 1 {
 							for idx, column := range result.columns {
-								if column.NameValue.String == columns[0] {
+								if column.NameValue.String == cols[0] {
 									column.UniqueValue = sql.NullBool{Bool: true, Valid: true}
 									result.columns[idx] = column
 									break
@@ -123,12 +112,15 @@ func parseDDL(strs ...string) (*ddl, error) {
 					continue
 				}
 				if strings.HasPrefix(fUpper, "PRIMARY KEY") {
-					for _, name := range getAllColumns(f) {
-						for idx, column := range result.columns {
-							if column.NameValue.String == name {
-								column.PrimaryKeyValue = sql.NullBool{Bool: true, Valid: true}
-								result.columns[idx] = column
-								break
+					cols, err := parseAllColumns(f)
+					if err == nil {
+						for _, name := range cols {
+							for idx, column := range result.columns {
+								if column.NameValue.String == name {
+									column.PrimaryKeyValue = sql.NullBool{Bool: true, Valid: true}
+									result.columns[idx] = column
+									break
+								}
 							}
 						}
 					}
--- a/gormlite/ddlmod_parse_all_columns.go
+++ b/gormlite/ddlmod_parse_all_columns.go
@@ -0,0 +1,117 @@
+package gormlite
+
+import (
+	"errors"
+	"fmt"
+)
+
+type parseAllColumnsState int
+
+const (
+	parseAllColumnsState_NONE parseAllColumnsState = iota
+	parseAllColumnsState_Beginning
+	parseAllColumnsState_ReadingRawName
+	parseAllColumnsState_ReadingQuotedName
+	parseAllColumnsState_EndOfName
+	parseAllColumnsState_State_End
+)
+
+func parseAllColumns(in string) ([]string, error) {
+	s := []rune(in)
+	columns := make([]string, 0)
+	state := parseAllColumnsState_NONE
+	quote := rune(0)
+	name := make([]rune, 0)
+	for i := 0; i < len(s); i++ {
+		switch state {
+		case parseAllColumnsState_NONE:
+			if s[i] == '(' {
+				state = parseAllColumnsState_Beginning
+			}
+		case parseAllColumnsState_Beginning:
+			if isSpace(s[i]) {
+				continue
+			}
+			if isQuote(s[i]) {
+				state = parseAllColumnsState_ReadingQuotedName
+				quote = s[i]
+				continue
+			}
+			if s[i] == '[' {
+				state = parseAllColumnsState_ReadingQuotedName
+				quote = ']'
+				continue
+			} else if s[i] == ')' {
+				return columns, fmt.Errorf("unexpected token: %s", string(s[i]))
+			}
+			state = parseAllColumnsState_ReadingRawName
+			name = append(name, s[i])
+		case parseAllColumnsState_ReadingRawName:
+			if isSeparator(s[i]) {
+				state = parseAllColumnsState_Beginning
+				columns = append(columns, string(name))
+				name = make([]rune, 0)
+				continue
+			}
+			if s[i] == ')' {
+				state = parseAllColumnsState_State_End
+				columns = append(columns, string(name))
+			}
+			if isQuote(s[i]) {
+				return nil, fmt.Errorf("unexpected token: %s", string(s[i]))
+			}
+			if isSpace(s[i]) {
+				state = parseAllColumnsState_EndOfName
+				columns = append(columns, string(name))
+				name = make([]rune, 0)
+				continue
+			}
+			name = append(name, s[i])
+		case parseAllColumnsState_ReadingQuotedName:
+			if s[i] == quote {
+				// check if quote character is escaped
+				if i+1 < len(s) && s[i+1] == quote {
+					name = append(name, quote)
+					i++
+					continue
+				}
+				state = parseAllColumnsState_EndOfName
+				columns = append(columns, string(name))
+				name = make([]rune, 0)
+				continue
+			}
+			name = append(name, s[i])
+		case parseAllColumnsState_EndOfName:
+			if isSpace(s[i]) {
+				continue
+			}
+			if isSeparator(s[i]) {
+				state = parseAllColumnsState_Beginning
+				continue
+			}
+			if s[i] == ')' {
+				state = parseAllColumnsState_State_End
+				continue
+			}
+			return nil, fmt.Errorf("unexpected token: %s", string(s[i]))
+		case parseAllColumnsState_State_End:
+			break
+		}
+	}
+	if state != parseAllColumnsState_State_End {
+		return nil, errors.New("unexpected end")
+	}
+	return columns, nil
+}
+
+func isSpace(r rune) bool {
+	return r == ' ' || r == '\t'
+}
+
+func isQuote(r rune) bool {
+	return r == '`' || r == '"' || r == '\''
+}
+
+func isSeparator(r rune) bool {
+	return r == ','
+}
--- a/gormlite/ddlmod_parse_all_columns_test.go
+++ b/gormlite/ddlmod_parse_all_columns_test.go
@@ -0,0 +1,48 @@
+package gormlite
+
+import "testing"
+
+func TestParseAllColumns(t *testing.T) {
+	tc := []struct {
+		name     string
+		input    string
+		expected []string
+	}{
+		{
+			name:     "Simple case",
+			input:    "PRIMARY KEY (column1, column2)",
+			expected: []string{"column1", "column2"},
+		},
+		{
+			name:     "Quoted column name",
+			input:    "PRIMARY KEY (`column,xxx`, \"column 2\", \"column)3\", 'column''4', \"column\"\"5\")",
+			expected: []string{"column,xxx", "column 2", "column)3", "column'4", "column\"5"},
+		},
+		{
+			name:     "Japanese column name",
+			input:    "PRIMARY KEY (カラム1, `カラム2`)",
+			expected: []string{"カラム1", "カラム2"},
+		},
+		{
+			name:     "Column name quoted with []",
+			input:    "PRIMARY KEY ([column1], [column2])",
+			expected: []string{"column1", "column2"},
+		},
+	}
+	for _, tt := range tc {
+		t.Run(tt.name, func(t *testing.T) {
+			cols, err := parseAllColumns(tt.input)
+			if err != nil {
+				t.Errorf("Failed to parse columns: %s", err)
+			}
+			if len(cols) != len(tt.expected) {
+				t.Errorf("Expected %d columns, got %d", len(tt.expected), len(cols))
+			}
+			for i, col := range cols {
+				if col != tt.expected[i] {
+					t.Errorf("Expected %s, got %s", tt.expected[i], col)
+				}
+			}
+		})
+	}
+}
--- a/gormlite/download.sh
+++ b/gormlite/download.sh
@@ -3,11 +3,13 @@ set -euo pipefail

 cd -P -- "$(dirname -- "$0")"

-curl -#OL "https://github.com/go-gorm/sqlite/raw/v1.5.6/ddlmod.go"
-curl -#OL "https://github.com/go-gorm/sqlite/raw/v1.5.6/ddlmod_test.go"
-curl -#OL "https://github.com/go-gorm/sqlite/raw/v1.5.6/error_translator.go"
-curl -#OL "https://github.com/go-gorm/sqlite/raw/v1.5.6/migrator.go"
-curl -#OL "https://github.com/go-gorm/sqlite/raw/v1.5.6/sqlite.go"
-curl -#OL "https://github.com/go-gorm/sqlite/raw/v1.5.6/sqlite_test.go"
-curl -#OL "https://github.com/go-gorm/sqlite/raw/v1.5.6/sqlite_test.go"
+curl -#OL "https://github.com/go-gorm/sqlite/raw/v1.5.7/ddlmod.go"
+curl -#OL "https://github.com/go-gorm/sqlite/raw/v1.5.7/ddlmod_test.go"
+curl -#OL "https://github.com/go-gorm/sqlite/raw/v1.5.7/ddlmod_parse_all_columns.go"
+curl -#OL "https://github.com/go-gorm/sqlite/raw/v1.5.7/ddlmod_parse_all_columns_test.go"
+curl -#OL "https://github.com/go-gorm/sqlite/raw/v1.5.7/error_translator.go"
+curl -#OL "https://github.com/go-gorm/sqlite/raw/v1.5.7/migrator.go"
+curl -#OL "https://github.com/go-gorm/sqlite/raw/v1.5.7/sqlite.go"
+curl -#OL "https://github.com/go-gorm/sqlite/raw/v1.5.7/sqlite_test.go"
+curl -#OL "https://github.com/go-gorm/sqlite/raw/v1.5.7/sqlite_test.go"
 curl -#L "https://github.com/glebarez/sqlite/raw/v1.11.0/sqlite_error_translator_test.go" > error_translator_test.go
--- a/gormlite/error_translator.go
+++ b/gormlite/error_translator.go
@@ -8,6 +8,7 @@ import (
 	"github.com/ncruces/go-sqlite3"
 )

+// Translate it will translate the error to native gorm errors.
 func (_Dialector) Translate(err error) error {
 	switch {
 	case
--- a/gormlite/go.mod
+++ b/gormlite/go.mod
@@ -5,7 +5,7 @@ go 1.21
 toolchain go1.23.0

 require (
-	github.com/ncruces/go-sqlite3 v0.21.0
+	github.com/ncruces/go-sqlite3 v0.21.3
 	gorm.io/gorm v1.25.12
 )

@@ -14,6 +14,6 @@ require (
 	github.com/jinzhu/now v1.1.5 // indirect
 	github.com/ncruces/julianday v1.0.0 // indirect
 	github.com/tetratelabs/wazero v1.8.2 // indirect
-	golang.org/x/sys v0.28.0 // indirect
+	golang.org/x/sys v0.29.0 // indirect
 	golang.org/x/text v0.21.0 // indirect
 )
--- a/gormlite/go.sum
+++ b/gormlite/go.sum
@@ -2,14 +2,14 @@ github.com/jinzhu/inflection v1.0.0 h1:K317FqzuhWc8YvSVlFMCCUb36O/S9MCKRDI7QkRKD
 github.com/jinzhu/inflection v1.0.0/go.mod h1:h+uFLlag+Qp1Va5pdKtLDYj+kHp5pxUVkryuEj+Srlc=
 github.com/jinzhu/now v1.1.5 h1:/o9tlHleP7gOFmsnYNz3RGnqzefHA47wQpKrrdTIwXQ=
 github.com/jinzhu/now v1.1.5/go.mod h1:d3SSVoowX0Lcu0IBviAWJpolVfI5UJVZZ7cO71lE/z8=
-github.com/ncruces/go-sqlite3 v0.21.0 h1:EwKFoy1hHEopN4sFZarmi+McXdbCcbTuLixhEayXVbQ=
-github.com/ncruces/go-sqlite3 v0.21.0/go.mod h1:zxMOaSG5kFYVFK4xQa0pdwIszqxqJ0W0BxBgwdrNjuA=
+github.com/ncruces/go-sqlite3 v0.21.3 h1:hHkfNQLcbnxPJZhC/RGw9SwP3bfkv/Y0xUHWsr1CdMQ=
+github.com/ncruces/go-sqlite3 v0.21.3/go.mod h1:zxMOaSG5kFYVFK4xQa0pdwIszqxqJ0W0BxBgwdrNjuA=
 github.com/ncruces/julianday v1.0.0 h1:fH0OKwa7NWvniGQtxdJRxAgkBMolni2BjDHaWTxqt7M=
 github.com/ncruces/julianday v1.0.0/go.mod h1:Dusn2KvZrrovOMJuOt0TNXL6tB7U2E8kvza5fFc9G7g=
 github.com/tetratelabs/wazero v1.8.2 h1:yIgLR/b2bN31bjxwXHD8a3d+BogigR952csSDdLYEv4=
 github.com/tetratelabs/wazero v1.8.2/go.mod h1:yAI0XTsMBhREkM/YDAK/zNou3GoiAce1P6+rp/wQhjs=
-golang.org/x/sys v0.28.0 h1:Fksou7UEQUWlKvIdsqzJmUmCX3cZuD2+P3XyyzwMhlA=
-golang.org/x/sys v0.28.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.29.0 h1:TPYlXGxvx1MGTn2GiZDhnjPA9wZzZeGKHHmKhHYvgaU=
+golang.org/x/sys v0.29.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/text v0.21.0 h1:zyQAAkrwaneQ066sspRyJaG9VNi/YJ1NfzcGB3hZ/qo=
 golang.org/x/text v0.21.0/go.mod h1:4IBbMaMmOPCJ8SecivzSH54+73PCFmPWxNTLm+vZkEQ=
 gorm.io/gorm v1.25.12 h1:I0u8i2hWQItBq1WfE0o2+WuL9+8L21K9e2HHSTE/0f8=
--- a/gormlite/sqlite.go
+++ b/gormlite/sqlite.go
@@ -14,6 +14,11 @@ import (
 	"github.com/ncruces/go-sqlite3/driver"
 )

+type _Dialector struct {
+	DSN  string
+	Conn gorm.ConnPool
+}
+
 // Open opens a GORM dialector from a data source name.
 func Open(dsn string) gorm.Dialector {
 	return &_Dialector{DSN: dsn}
@@ -24,11 +29,6 @@ func OpenDB(db gorm.ConnPool) gorm.Dialector {
 	return &_Dialector{Conn: db}
 }

-type _Dialector struct {
-	DSN  string
-	Conn gorm.ConnPool
-}
-
 func (dialector _Dialector) Name() string {
 	return "sqlite"
 }
--- a/internal/dotlk/dotlk.go
+++ b/internal/dotlk/dotlk.go
@@ -0,0 +1,29 @@
+package dotlk
+
+import (
+	"errors"
+	"io/fs"
+	"os"
+)
+
+// LockShm creates a directory on disk to prevent SQLite
+// from using this path for a shared memory file.
+func LockShm(name string) error {
+	err := os.Mkdir(name, 0777)
+	if errors.Is(err, fs.ErrExist) {
+		s, err := os.Lstat(name)
+		if err == nil && s.IsDir() {
+			return nil
+		}
+	}
+	return err
+}
+
+// Unlock removes the lock or shared memory file.
+func Unlock(name string) error {
+	err := os.Remove(name)
+	if errors.Is(err, fs.ErrNotExist) {
+		return nil
+	}
+	return err
+}
--- a/internal/dotlk/dotlk_other.go
+++ b/internal/dotlk/dotlk_other.go
@@ -0,0 +1,13 @@
+//go:build !unix
+
+package dotlk
+
+import "os"
+
+// TryLock returns nil if it acquired the lock,
+// fs.ErrExist if another process has the lock.
+func TryLock(name string) error {
+	f, err := os.OpenFile(name, os.O_RDWR|os.O_CREATE|os.O_EXCL, 0666)
+	f.Close()
+	return err
+}
--- a/internal/dotlk/dotlk_unix.go
+++ b/internal/dotlk/dotlk_unix.go
@@ -0,0 +1,50 @@
+//go:build unix
+
+package dotlk
+
+import (
+	"errors"
+	"io/fs"
+	"os"
+	"strconv"
+
+	"golang.org/x/sys/unix"
+)
+
+// TryLock returns nil if it acquired the lock,
+// fs.ErrExist if another process has the lock.
+func TryLock(name string) error {
+	for retry := true; retry; retry = false {
+		f, err := os.OpenFile(name, os.O_RDWR|os.O_CREATE|os.O_EXCL, 0666)
+		if err == nil {
+			f.WriteString(strconv.Itoa(os.Getpid()))
+			f.Close()
+			return nil
+		}
+		if !errors.Is(err, fs.ErrExist) {
+			return err
+		}
+		if !removeStale(name) {
+			break
+		}
+	}
+	return fs.ErrExist
+}
+
+func removeStale(name string) bool {
+	buf, err := os.ReadFile(name)
+	if err != nil {
+		return errors.Is(err, fs.ErrNotExist)
+	}
+
+	pid, err := strconv.Atoi(string(buf))
+	if err != nil {
+		return false
+	}
+	if unix.Kill(pid, 0) == nil {
+		return false
+	}
+
+	err = os.Remove(name)
+	return err == nil || errors.Is(err, fs.ErrNotExist)
+}
--- a/internal/testcfg/testcfg.go
+++ b/internal/testcfg/testcfg.go
@@ -7,14 +7,18 @@ import (
 	"github.com/tetratelabs/wazero"

 	"github.com/ncruces/go-sqlite3"
+	"github.com/ncruces/go-sqlite3/internal/util"
 )

 // notest

 func init() {
-	sqlite3.RuntimeConfig = wazero.NewRuntimeConfig().
-		WithMemoryLimitPages(512)
-
+	if util.CompilerSupported() {
+		sqlite3.RuntimeConfig = wazero.NewRuntimeConfigCompiler()
+	} else {
+		sqlite3.RuntimeConfig = wazero.NewRuntimeConfigInterpreter()
+	}
+	sqlite3.RuntimeConfig = sqlite3.RuntimeConfig.WithMemoryLimitPages(512)
 	if os.Getenv("CI") != "" {
 		path := filepath.Join(os.TempDir(), "wazero")
 		if err := os.MkdirAll(path, 0777); err == nil {
--- a/internal/util/compiler.go
+++ b/internal/util/compiler.go
@@ -0,0 +1,27 @@
+package util
+
+import (
+	"runtime"
+
+	"golang.org/x/sys/cpu"
+)
+
+func CompilerSupported() bool {
+	switch runtime.GOOS {
+	case "linux", "android",
+		"windows", "darwin",
+		"freebsd", "netbsd", "dragonfly",
+		"solaris", "illumos":
+		break
+	default:
+		return false
+	}
+	switch runtime.GOARCH {
+	case "amd64":
+		return cpu.X86.HasSSE41
+	case "arm64":
+		return true
+	default:
+		return false
+	}
+}
--- a/internal/util/mmap_unix.go
+++ b/internal/util/mmap_unix.go
@@ -39,13 +39,13 @@ func (s *mmapState) new(ctx context.Context, mod api.Module, size int32) *Mapped
 	// Save the newly allocated region.
 	ptr := uint32(stack[0])
 	buf := View(mod, ptr, uint64(size))
-	addr := unsafe.Pointer(&buf[0])
-	s.regions = append(s.regions, &MappedRegion{
+	res := &MappedRegion{
 		Ptr:  ptr,
-		addr: addr,
 		size: size,
-	})
-	return s.regions[len(s.regions)-1]
+		addr: unsafe.Pointer(&buf[0]),
+	}
+	s.regions = append(s.regions, res)
+	return res
 }

 type MappedRegion struct {
--- a/internal/util/module.go
+++ b/internal/util/module.go
@@ -8,6 +8,8 @@ import (
 	"github.com/ncruces/go-sqlite3/internal/alloc"
 )

+type ConnKey struct{}
+
 type moduleKey struct{}
 type moduleState struct {
 	mmapState
--- a/sqlite.go
+++ b/sqlite.go
@@ -11,7 +11,6 @@ import (

 	"github.com/tetratelabs/wazero"
 	"github.com/tetratelabs/wazero/api"
-	"github.com/tetratelabs/wazero/experimental"

 	"github.com/ncruces/go-sqlite3/internal/util"
 	"github.com/ncruces/go-sqlite3/vfs"
@@ -49,14 +48,18 @@ func compileSQLite() {
 	ctx := context.Background()
 	cfg := RuntimeConfig
 	if cfg == nil {
-		cfg = wazero.NewRuntimeConfig()
-		if bits.UintSize >= 64 {
-			cfg = cfg.WithMemoryLimitPages(4096) // 256MB
+		if util.CompilerSupported() {
+			cfg = wazero.NewRuntimeConfigCompiler()
 		} else {
+			cfg = wazero.NewRuntimeConfigInterpreter()
+		}
+		if bits.UintSize < 64 {
 			cfg = cfg.WithMemoryLimitPages(512) // 32MB
+		} else {
+			cfg = cfg.WithMemoryLimitPages(4096) // 256MB
 		}
 	}
-	cfg = cfg.WithCoreFeatures(api.CoreFeaturesV2 | experimental.CoreFeaturesThreads)
+	cfg = cfg.WithCoreFeatures(api.CoreFeaturesV2)

 	instance.runtime = wazero.NewRuntimeWithConfig(ctx, cfg)

@@ -265,10 +268,11 @@ func (a *arena) mark() (reset func()) {
 	ptrs := len(a.ptrs)
 	next := a.next
 	return func() {
-		for _, ptr := range a.ptrs[ptrs:] {
+		rest := a.ptrs[ptrs:]
+		for _, ptr := range a.ptrs[:ptrs] {
 			a.sqlt.free(ptr)
 		}
-		a.ptrs = a.ptrs[:ptrs]
+		a.ptrs = rest
 		a.next = next
 	}
 }
--- a/sqlite3/base64.patch
+++ b/sqlite3/base64.patch
@@ -0,0 +1,11 @@
+--- ext/base64.c.orig
+++ ext/base64.c
+@@ -198,7 +198,7 @@
+       deliberate_fall_through; /* FALLTHRU */
+     case 1:
+       pOut[0] = (qv>>16) & 0xff;
+-      deliberate_fall_through; /* FALLTHRU */
+      break; /* FALLTHRU */
+     }
+     pOut += nbo;
+   }
--- a/sqlite3/busy_timeout.patch
+++ b/sqlite3/busy_timeout.patch
@@ -2,7 +2,7 @@
 # handle, and interrupt, sqlite3_busy_timeout.
 --- sqlite3.c.orig
 +++ sqlite3.c
-@@ -182928,7 +182928,7 @@
+@@ -183054,7 +183054,7 @@
   if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
 #endif
   if( ms>0 ){
--- a/sqlite3/download.sh
+++ b/sqlite3/download.sh
@@ -3,7 +3,7 @@ set -euo pipefail

 cd -P -- "$(dirname -- "$0")"

-curl -#OL "https://sqlite.org/2024/sqlite-amalgamation-3470200.zip"
+curl -#OL "https://sqlite.org/2025/sqlite-amalgamation-3480000.zip"
 unzip -d . sqlite-amalgamation-*.zip
 mv sqlite-amalgamation-*/sqlite3.c .
 mv sqlite-amalgamation-*/sqlite3.h .
@@ -17,29 +17,32 @@ rm -rf sqlite-amalgamation-*
 # mv sqlite-snapshot-*/sqlite3ext.h .
 # rm -rf sqlite-snapshot-*

-cat *.patch | patch --no-backup-if-mismatch
-
 mkdir -p ext/
 cd ext/
-curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.47.2/ext/misc/anycollseq.c"
-curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.47.2/ext/misc/base64.c"
-curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.47.2/ext/misc/decimal.c"
-curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.47.2/ext/misc/ieee754.c"
-curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.47.2/ext/misc/regexp.c"
-curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.47.2/ext/misc/series.c"
-curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.47.2/ext/misc/spellfix.c"
-curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.47.2/ext/misc/uint.c"
+curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.48.0/ext/misc/anycollseq.c"
+curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.48.0/ext/misc/base64.c"
+curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.48.0/ext/misc/decimal.c"
+curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.48.0/ext/misc/ieee754.c"
+curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.48.0/ext/misc/regexp.c"
+curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.48.0/ext/misc/series.c"
+curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.48.0/ext/misc/spellfix.c"
+curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.48.0/ext/misc/uint.c"
 cd ~-

 cd ../vfs/tests/mptest/testdata/
-curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.47.2/mptest/mptest.c"
-curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.47.2/mptest/config01.test"
-curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.47.2/mptest/config02.test"
-curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.47.2/mptest/crash01.test"
-curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.47.2/mptest/crash02.subtest"
-curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.47.2/mptest/multiwrite01.test"
+curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.48.0/mptest/config01.test"
+curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.48.0/mptest/config02.test"
+curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.48.0/mptest/crash01.test"
+curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.48.0/mptest/crash02.subtest"
+curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.48.0/mptest/multiwrite01.test"
 cd ~-

-cd ../vfs/tests/speedtest1/testdata/
-curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.47.2/test/speedtest1.c"
-cd ~-
+cd ../vfs/tests/mptest/wasm/
+curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.48.0/mptest/mptest.c"
+cd ~-
+
+cd ../vfs/tests/speedtest1/wasm/
+curl -#OL "https://github.com/sqlite/sqlite/raw/version-3.48.0/test/speedtest1.c"
+cd ~-
+
+cat *.patch | patch -p0 --no-backup-if-mismatch
--- a/sqlite3/sqlite_cfg.h
+++ b/sqlite3/sqlite_cfg.h
@@ -18,8 +18,6 @@
 #define HAVE_STDINT_H 1
 #define HAVE_INTTYPES_H 1

-#define LONGDOUBLE_TYPE double
-
 #define HAVE_LOG2 1
 #define HAVE_LOG10 1
 #define HAVE_ISNAN 1
@@ -35,10 +33,6 @@
 #define HAVE_MALLOC_H 1
 #define HAVE_MALLOC_USABLE_SIZE 1

-// Because Wasm does not support shared memory,
-// SQLite disables WAL for Wasm builds.
-#undef SQLITE_OMIT_WAL
-
 // Implemented in vfs.c.
 int localtime_s(struct tm *const pTm, time_t const *const pTime);

--- a/sqlite3/vfs.c
+++ b/sqlite3/vfs.c
@@ -162,5 +162,10 @@ int sqlite3_os_init() {
  return SQLITE_OK;
 }

+int sqlite3_invoke_busy_handler_go(sqlite3_int64 token) {
+  void **ap = (void **)&token;
+  return ((int(*)(void *))(ap[0]))(ap[1]);
+}
+
 static_assert(offsetof(sqlite3_vfs, zName) == 16, "Unexpected offset");
 static_assert(offsetof(struct go_file, handle) == 4, "Unexpected offset");
--- a/sqlite3/vfs_find.patch
+++ b/sqlite3/vfs_find.patch
@@ -1,7 +1,7 @@
 # Remove VFS registration. Go handles it.
 --- sqlite3.c.orig
 +++ sqlite3.c
-@@ -26603,7 +26603,7 @@
+@@ -26623,7 +26623,7 @@
   sqlite3_free(p);
   return sqlite3_os_init();
 }
@@ -10,7 +10,7 @@
 /*
 ** The list of all registered VFS implementations.
 */
-@@ -26700,7 +26700,7 @@
+@@ -26720,7 +26720,7 @@
   sqlite3_mutex_leave(mutex);
   return SQLITE_OK;
 }
--- a/tests/conn_test.go
+++ b/tests/conn_test.go
@@ -130,8 +130,6 @@ func TestConn_SetInterrupt(t *testing.T) {
 		t.Fatal(err)
 	}

-	db.SetInterrupt(context.Background())
-
 	stmt, _, err := db.Prepare(`
 		WITH RECURSIVE
 		  fibonacci (curr, next)
@@ -148,7 +146,6 @@ func TestConn_SetInterrupt(t *testing.T) {
 	}
 	defer stmt.Close()

-	db.SetInterrupt(ctx)
 	go func() {
 		time.Sleep(time.Millisecond)
 		cancel()
--- a/tests/parallel/parallel_test.go
+++ b/tests/parallel/parallel_test.go
@@ -140,7 +140,7 @@ func Test_xts(t *testing.T) {
 	testIntegrity(t, name)
 }

-func TestMultiProcess(t *testing.T) {
+func Test_MultiProcess_rollback(t *testing.T) {
 	if !vfs.SupportsFileLocking {
 		t.Skip("skipping without locks")
 	}
@@ -149,7 +149,7 @@ func TestMultiProcess(t *testing.T) {
 	}

 	file := filepath.Join(t.TempDir(), "test.db")
-	t.Setenv("TestMultiProcess_dbfile", file)
+	t.Setenv("Test_MultiProcess_dbfile", file)

 	name := "file:" + filepath.ToSlash(file) +
 		"?_pragma=busy_timeout(10000)" +
@@ -161,7 +161,7 @@ func TestMultiProcess(t *testing.T) {
 		t.Fatal(err)
 	}

-	cmd := exec.Command(exe, append(os.Args[1:], "-test.v", "-test.run=TestChildProcess")...)
+	cmd := exec.Command(exe, append(os.Args[1:], "-test.v", "-test.run=Test_ChildProcess_rollback")...)
 	out, err := cmd.StdoutPipe()
 	if err != nil {
 		t.Fatal(err)
@@ -185,8 +185,8 @@ func TestMultiProcess(t *testing.T) {
 	testIntegrity(t, name)
 }

-func TestChildProcess(t *testing.T) {
-	file := os.Getenv("TestMultiProcess_dbfile")
+func Test_ChildProcess_rollback(t *testing.T) {
+	file := os.Getenv("Test_MultiProcess_dbfile")
 	if file == "" || testing.Short() {
 		t.SkipNow()
 	}
@@ -199,6 +199,65 @@ func TestChildProcess(t *testing.T) {
 	testParallel(t, name, 1000)
 }

+func Test_MultiProcess_wal(t *testing.T) {
+	if !vfs.SupportsFileLocking {
+		t.Skip("skipping without locks")
+	}
+	if testing.Short() {
+		t.Skip("skipping in short mode")
+	}
+
+	file := filepath.Join(t.TempDir(), "test.db")
+	t.Setenv("Test_MultiProcess_dbfile", file)
+
+	name := "file:" + filepath.ToSlash(file) +
+		"?_pragma=busy_timeout(10000)" +
+		"&_pragma=journal_mode(wal)" +
+		"&_pragma=synchronous(off)"
+
+	exe, err := os.Executable()
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	cmd := exec.Command(exe, append(os.Args[1:], "-test.v", "-test.run=Test_ChildProcess_wal")...)
+	out, err := cmd.StdoutPipe()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if err := cmd.Start(); err != nil {
+		t.Fatal(err)
+	}
+
+	var buf [3]byte
+	// Wait for child to start.
+	if _, err := io.ReadFull(out, buf[:]); err != nil {
+		t.Fatal(err)
+	} else if str := string(buf[:]); str != "===" {
+		t.Fatal(str)
+	}
+
+	testParallel(t, name, 1000)
+	if err := cmd.Wait(); err != nil {
+		t.Error(err)
+	}
+	testIntegrity(t, name)
+}
+
+func Test_ChildProcess_wal(t *testing.T) {
+	file := os.Getenv("Test_MultiProcess_dbfile")
+	if file == "" || testing.Short() {
+		t.SkipNow()
+	}
+
+	name := "file:" + filepath.ToSlash(file) +
+		"?_pragma=busy_timeout(10000)" +
+		"&_pragma=journal_mode(wal)" +
+		"&_pragma=synchronous(off)"
+
+	testParallel(t, name, 1000)
+}
+
 func Benchmark_parallel(b *testing.B) {
 	if !vfs.SupportsSharedMemory {
 		b.Skip("skipping without shared memory")
--- a/util/sql3util/parse.go
+++ b/util/sql3util/parse.go
@@ -17,7 +17,7 @@ const (
 )

 var (
-	//go:embed parse/sql3parse_table.wasm
+	//go:embed wasm/sql3parse_table.wasm
 	binary   []byte
 	once     sync.Once
 	runtime  wazero.Runtime
--- a/util/sql3util/parse/sql3parse_table.wasm
+++ b/util/sql3util/parse/sql3parse_table.wasm
--- a/util/sql3util/parse/.gitignore
+++ b/util/sql3util/parse/.gitignore
--- a/util/sql3util/parse/build.sh
+++ b/util/sql3util/parse/build.sh
--- a/util/sql3util/parse/download.sh
+++ b/util/sql3util/parse/download.sh
--- a/util/sql3util/parse/main.c
+++ b/util/sql3util/parse/main.c
--- a/util/sql3util/wasm/sql3parse_table.wasm
+++ b/util/sql3util/wasm/sql3parse_table.wasm
--- a/util/vfsutil/wrap.go
+++ b/util/vfsutil/wrap.go
@@ -38,18 +38,18 @@ func WrapLockState(f vfs.File) vfs.LockLevel {
 	return vfs.LOCK_EXCLUSIVE + 1 // UNKNOWN_LOCK
 }

-// WrapPersistentWAL helps wrap [vfs.FilePersistentWAL].
-func WrapPersistentWAL(f vfs.File) bool {
-	if f, ok := f.(vfs.FilePersistentWAL); ok {
-		return f.PersistentWAL()
+// WrapPersistWAL helps wrap [vfs.FilePersistWAL].
+func WrapPersistWAL(f vfs.File) bool {
+	if f, ok := f.(vfs.FilePersistWAL); ok {
+		return f.PersistWAL()
 	}
 	return false
 }

-// WrapSetPersistentWAL helps wrap [vfs.FilePersistentWAL].
-func WrapSetPersistentWAL(f vfs.File, keepWAL bool) {
-	if f, ok := f.(vfs.FilePersistentWAL); ok {
-		f.SetPersistentWAL(keepWAL)
+// WrapSetPersistWAL helps wrap [vfs.FilePersistWAL].
+func WrapSetPersistWAL(f vfs.File, keepWAL bool) {
+	if f, ok := f.(vfs.FilePersistWAL); ok {
+		f.SetPersistWAL(keepWAL)
 	}
 }

@@ -99,6 +99,14 @@ func WrapOverwrite(f vfs.File) error {
 	return sqlite3.NOTFOUND
 }

+// WrapSyncSuper helps wrap [vfs.FileSync].
+func WrapSyncSuper(f vfs.File, super string) error {
+	if f, ok := f.(vfs.FileSync); ok {
+		return f.SyncSuper(super)
+	}
+	return sqlite3.NOTFOUND
+}
+
 // WrapCommitPhaseTwo helps wrap [vfs.FileCommitPhaseTwo].
 func WrapCommitPhaseTwo(f vfs.File) error {
 	if f, ok := f.(vfs.FileCommitPhaseTwo); ok {
@@ -153,6 +161,13 @@ func WrapPragma(f vfs.File, name, value string) (string, error) {
 	return "", sqlite3.NOTFOUND
 }

+// WrapBusyHandler helps wrap [vfs.FilePragma].
+func WrapBusyHandler(f vfs.File, handler func() bool) {
+	if f, ok := f.(vfs.FileBusyHandler); ok {
+		f.BusyHandler(handler)
+	}
+}
+
 // WrapSharedMemory helps wrap [vfs.FileSharedMemory].
 func WrapSharedMemory(f vfs.File) vfs.SharedMemory {
 	if f, ok := f.(vfs.FileSharedMemory); ok {
--- a/vfs/README.md
+++ b/vfs/README.md
@@ -48,11 +48,6 @@ On Unix, this package may use `mmap` to implement
 [shared-memory for the WAL-index](https://sqlite.org/wal.html#implementation_of_shared_memory_for_the_wal_index),
 like SQLite.

-With [BSD locks](https://man.freebsd.org/cgi/man.cgi?query=flock&sektion=2)
-a WAL database can only be accessed by a single proccess.
-Other processes that attempt to access a database locked with BSD locks,
-will fail with the [`SQLITE_PROTOCOL`](https://sqlite.org/rescode.html#protocol) error code.
-
 On Windows, this package may use `MapViewOfFile`, like SQLite.

 You can also opt into a cross-platform, in-process, memory sharing implementation
--- a/vfs/adiantum/hbsh.go
+++ b/vfs/adiantum/hbsh.go
@@ -238,11 +238,11 @@ func (h *hbshFile) LockState() vfs.LockLevel {
 }

 func (h *hbshFile) PersistentWAL() bool {
-	return vfsutil.WrapPersistentWAL(h.File) // notest
+	return vfsutil.WrapPersistWAL(h.File) // notest
 }

 func (h *hbshFile) SetPersistentWAL(keepWAL bool) {
-	vfsutil.WrapSetPersistentWAL(h.File, keepWAL) // notest
+	vfsutil.WrapSetPersistWAL(h.File, keepWAL) // notest
 }

 func (h *hbshFile) HasMoved() (bool, error) {
@@ -253,6 +253,10 @@ func (h *hbshFile) Overwrite() error {
 	return vfsutil.WrapOverwrite(h.File) // notest
 }

+func (h *hbshFile) SyncSuper(super string) error {
+	return vfsutil.WrapSyncSuper(h.File, super) // notest
+}
+
 func (h *hbshFile) CommitPhaseTwo() error {
 	return vfsutil.WrapCommitPhaseTwo(h.File) // notest
 }
@@ -276,3 +280,7 @@ func (h *hbshFile) CheckpointStart() {
 func (h *hbshFile) CheckpointDone() {
 	vfsutil.WrapCheckpointDone(h.File) // notest
 }
+
+func (h *hbshFile) BusyHandler(handler func() bool) {
+	vfsutil.WrapBusyHandler(h.File, handler) // notest
+}
--- a/vfs/api.go
+++ b/vfs/api.go
@@ -65,14 +65,14 @@ type FileLockState interface {
 	LockState() LockLevel
 }

-// FilePersistentWAL extends File to implement the
+// FilePersistWAL extends File to implement the
 // SQLITE_FCNTL_PERSIST_WAL file control opcode.
 //
 // https://sqlite.org/c3ref/c_fcntl_begin_atomic_write.html#sqlitefcntlpersistwal
-type FilePersistentWAL interface {
+type FilePersistWAL interface {
 	File
-	PersistentWAL() bool
-	SetPersistentWAL(bool)
+	PersistWAL() bool
+	SetPersistWAL(bool)
 }

 // FilePowersafeOverwrite extends File to implement the
@@ -121,6 +121,15 @@ type FileOverwrite interface {
 	Overwrite() error
 }

+// FileSync extends File to implement the
+// SQLITE_FCNTL_SYNC file control opcode.
+//
+// https://sqlite.org/c3ref/c_fcntl_begin_atomic_write.html#sqlitefcntlsync
+type FileSync interface {
+	File
+	SyncSuper(super string) error
+}
+
 // FileCommitPhaseTwo extends File to implement the
 // SQLITE_FCNTL_COMMIT_PHASETWO file control opcode.
 //
@@ -162,6 +171,15 @@ type FilePragma interface {
 	Pragma(name, value string) (string, error)
 }

+// FileBusyHandler extends File to implement the
+// SQLITE_FCNTL_BUSYHANDLER file control opcode.
+//
+// https://sqlite.org/c3ref/c_fcntl_begin_atomic_write.html#sqlitefcntlbusyhandler
+type FileBusyHandler interface {
+	File
+	BusyHandler(func() bool)
+}
+
 // FileSharedMemory extends File to possibly implement
 // shared-memory for the WAL-index.
 // The same shared-memory instance must be returned
@@ -191,3 +209,8 @@ type fileControl interface {
 	File
 	fileControl(ctx context.Context, mod api.Module, op _FcntlOpcode, pArg uint32) _ErrorCode
 }
+
+type filePDB interface {
+	File
+	SetDB(any)
+}
--- a/vfs/const.go
+++ b/vfs/const.go
@@ -225,6 +225,7 @@ const (
 	_FCNTL_EXTERNAL_READER       _FcntlOpcode = 40
 	_FCNTL_CKSM_FILE             _FcntlOpcode = 41
 	_FCNTL_RESET_CACHE           _FcntlOpcode = 42
+	_FCNTL_NULL_IO               _FcntlOpcode = 43
 )

 // https://sqlite.org/c3ref/c_shm_exclusive.html
--- a/vfs/file.go
+++ b/vfs/file.go
@@ -6,7 +6,6 @@ import (
 	"io/fs"
 	"os"
 	"path/filepath"
-	"runtime"
 	"syscall"

 	"github.com/ncruces/go-sqlite3/util/osutil"
@@ -41,7 +40,7 @@ func (vfsOS) Delete(path string, syncDir bool) error {
 	if err != nil {
 		return err
 	}
-	if runtime.GOOS != "windows" && syncDir {
+	if canSyncDirs && syncDir {
 		f, err := os.Open(filepath.Dir(path))
 		if err != nil {
 			return _OK
@@ -120,9 +119,9 @@ func (vfsOS) OpenFilename(name *Filename, flags OpenFlag) (File, OpenFlag, error
 		File:     f,
 		psow:     true,
 		readOnly: flags&OPEN_READONLY != 0,
-		syncDir: runtime.GOOS != "windows" &&
-			flags&(OPEN_CREATE) != 0 &&
-			flags&(OPEN_MAIN_JOURNAL|OPEN_SUPER_JOURNAL|OPEN_WAL) != 0,
+		syncDir: canSyncDirs &&
+			flags&(OPEN_MAIN_JOURNAL|OPEN_SUPER_JOURNAL|OPEN_WAL) != 0 &&
+			flags&(OPEN_CREATE) != 0,
 		shm: NewSharedMemory(name.String()+"-shm", flags),
 	}
 	return &file, flags, nil
@@ -143,7 +142,7 @@ var (
 	_ FileLockState          = &vfsFile{}
 	_ FileHasMoved           = &vfsFile{}
 	_ FileSizeHint           = &vfsFile{}
-	_ FilePersistentWAL      = &vfsFile{}
+	_ FilePersistWAL         = &vfsFile{}
 	_ FilePowersafeOverwrite = &vfsFile{}
 )

@@ -163,7 +162,7 @@ func (f *vfsFile) Sync(flags SyncFlag) error {
 	if err != nil {
 		return err
 	}
-	if runtime.GOOS != "windows" && f.syncDir {
+	if canSyncDirs && f.syncDir {
 		f.syncDir = false
 		d, err := os.Open(filepath.Dir(f.File.Name()))
 		if err != nil {
@@ -218,6 +217,6 @@ func (f *vfsFile) HasMoved() (bool, error) {

 func (f *vfsFile) LockState() LockLevel            { return f.lock }
 func (f *vfsFile) PowersafeOverwrite() bool        { return f.psow }
-func (f *vfsFile) PersistentWAL() bool             { return f.keepWAL }
+func (f *vfsFile) PersistWAL() bool                { return f.keepWAL }
 func (f *vfsFile) SetPowersafeOverwrite(psow bool) { f.psow = psow }
-func (f *vfsFile) SetPersistentWAL(keepWAL bool)   { f.keepWAL = keepWAL }
+func (f *vfsFile) SetPersistWAL(keepWAL bool)      { f.keepWAL = keepWAL }
--- a/vfs/lock.go
+++ b/vfs/lock.go
@@ -20,12 +20,10 @@ const (
 )

 func (f *vfsFile) Lock(lock LockLevel) error {
-	// Argument check. SQLite never explicitly requests a pending lock.
-	if lock != LOCK_SHARED && lock != LOCK_RESERVED && lock != LOCK_EXCLUSIVE {
-		panic(util.AssertErr())
-	}
-
 	switch {
+	case lock != LOCK_SHARED && lock != LOCK_RESERVED && lock != LOCK_EXCLUSIVE:
+		// Argument check. SQLite never explicitly requests a pending lock.
+		panic(util.AssertErr())
 	case f.lock < LOCK_NONE || f.lock > LOCK_EXCLUSIVE:
 		// Connection state check.
 		panic(util.AssertErr())
@@ -87,13 +85,12 @@ func (f *vfsFile) Lock(lock LockLevel) error {
 }

 func (f *vfsFile) Unlock(lock LockLevel) error {
-	// Argument check.
-	if lock != LOCK_NONE && lock != LOCK_SHARED {
+	switch {
+	case lock != LOCK_NONE && lock != LOCK_SHARED:
+		// Argument check.
 		panic(util.AssertErr())
-	}
-
-	// Connection state check.
-	if f.lock < LOCK_NONE || f.lock > LOCK_EXCLUSIVE {
+	case f.lock < LOCK_NONE || f.lock > LOCK_EXCLUSIVE:
+		// Connection state check.
 		panic(util.AssertErr())
 	}

--- a/vfs/memdb/memdb.go
+++ b/vfs/memdb/memdb.go
@@ -62,11 +62,11 @@ func (memVFS) Open(name string, flags vfs.OpenFlag) (vfs.File, vfs.OpenFlag, err
 }

 func (memVFS) Delete(name string, dirSync bool) error {
-	return sqlite3.IOERR_DELETE
+	return sqlite3.IOERR_DELETE_NOENT // used to delete journals
 }

 func (memVFS) Access(name string, flag vfs.AccessFlag) (bool, error) {
-	return false, nil
+	return false, nil // used to check for journals
 }

 func (memVFS) FullPathname(name string) (string, error) {
--- a/vfs/os_bsd.go
+++ b/vfs/os_bsd.go
@@ -9,11 +9,11 @@ import (
 )

 func osGetSharedLock(file *os.File) _ErrorCode {
-	return osLock(file, unix.LOCK_SH|unix.LOCK_NB, _IOERR_RDLOCK)
+	return osFlock(file, unix.LOCK_SH|unix.LOCK_NB, _IOERR_RDLOCK)
 }

 func osGetReservedLock(file *os.File) _ErrorCode {
-	rc := osLock(file, unix.LOCK_EX|unix.LOCK_NB, _IOERR_LOCK)
+	rc := osFlock(file, unix.LOCK_EX|unix.LOCK_NB, _IOERR_LOCK)
 	if rc == _BUSY {
 		// The documentation states that a lock is upgraded by
 		// releasing the previous lock, then acquiring the new lock.
@@ -37,7 +37,7 @@ func osGetExclusiveLock(file *os.File, state *LockLevel) _ErrorCode {
 }

 func osDowngradeLock(file *os.File, _ LockLevel) _ErrorCode {
-	rc := osLock(file, unix.LOCK_SH|unix.LOCK_NB, _IOERR_RDLOCK)
+	rc := osFlock(file, unix.LOCK_SH|unix.LOCK_NB, _IOERR_RDLOCK)
 	if rc == _BUSY {
 		// The documentation states that a lock is downgraded by
 		// releasing the previous lock then acquiring the new lock.
@@ -66,7 +66,36 @@ func osCheckReservedLock(file *os.File) (bool, _ErrorCode) {
 	return lock == unix.F_WRLCK, rc
 }

-func osLock(file *os.File, how int, def _ErrorCode) _ErrorCode {
+func osFlock(file *os.File, how int, def _ErrorCode) _ErrorCode {
 	err := unix.Flock(int(file.Fd()), how)
 	return osLockErrorCode(err, def)
 }
+
+func osReadLock(file *os.File, start, len int64) _ErrorCode {
+	return osLock(file, unix.F_RDLCK, start, len, _IOERR_RDLOCK)
+}
+
+func osWriteLock(file *os.File, start, len int64) _ErrorCode {
+	return osLock(file, unix.F_WRLCK, start, len, _IOERR_LOCK)
+}
+
+func osLock(file *os.File, typ int16, start, len int64, def _ErrorCode) _ErrorCode {
+	err := unix.FcntlFlock(file.Fd(), unix.F_SETLK, &unix.Flock_t{
+		Type:  typ,
+		Start: start,
+		Len:   len,
+	})
+	return osLockErrorCode(err, def)
+}
+
+func osUnlock(file *os.File, start, len int64) _ErrorCode {
+	err := unix.FcntlFlock(file.Fd(), unix.F_SETLK, &unix.Flock_t{
+		Type:  unix.F_UNLCK,
+		Start: start,
+		Len:   len,
+	})
+	if err != nil {
+		return _IOERR_UNLOCK
+	}
+	return _OK
+}
--- a/vfs/os_darwin.go
+++ b/vfs/os_darwin.go
@@ -56,16 +56,12 @@ func osAllocate(file *os.File, size int64) error {
 	return file.Truncate(size)
 }

-func osUnlock(file *os.File, start, len int64) _ErrorCode {
-	err := unix.FcntlFlock(file.Fd(), _F_OFD_SETLK, &unix.Flock_t{
-		Type:  unix.F_UNLCK,
-		Start: start,
-		Len:   len,
-	})
-	if err != nil {
-		return _IOERR_UNLOCK
-	}
-	return _OK
+func osReadLock(file *os.File, start, len int64, timeout time.Duration) _ErrorCode {
+	return osLock(file, unix.F_RDLCK, start, len, timeout, _IOERR_RDLOCK)
+}
+
+func osWriteLock(file *os.File, start, len int64, timeout time.Duration) _ErrorCode {
+	return osLock(file, unix.F_WRLCK, start, len, timeout, _IOERR_LOCK)
 }

 func osLock(file *os.File, typ int16, start, len int64, timeout time.Duration, def _ErrorCode) _ErrorCode {
@@ -88,10 +84,14 @@ func osLock(file *os.File, typ int16, start, len int64, timeout time.Duration, d
 	return osLockErrorCode(err, def)
 }

-func osReadLock(file *os.File, start, len int64, timeout time.Duration) _ErrorCode {
-	return osLock(file, unix.F_RDLCK, start, len, timeout, _IOERR_RDLOCK)
-}
-
-func osWriteLock(file *os.File, start, len int64, timeout time.Duration) _ErrorCode {
-	return osLock(file, unix.F_WRLCK, start, len, timeout, _IOERR_LOCK)
+func osUnlock(file *os.File, start, len int64) _ErrorCode {
+	err := unix.FcntlFlock(file.Fd(), _F_OFD_SETLK, &unix.Flock_t{
+		Type:  unix.F_UNLCK,
+		Start: start,
+		Len:   len,
+	})
+	if err != nil {
+		return _IOERR_UNLOCK
+	}
+	return _OK
 }
--- a/vfs/os_dotlk.go
+++ b/vfs/os_dotlk.go
@@ -7,6 +7,8 @@ import (
 	"io/fs"
 	"os"
 	"sync"
+
+	"github.com/ncruces/go-sqlite3/internal/dotlk"
 )

 var (
@@ -28,12 +30,10 @@ func osGetSharedLock(file *os.File) _ErrorCode {
 	name := file.Name()
 	locker := vfsDotLocks[name]
 	if locker == nil {
-		f, err := os.OpenFile(name+".lock", os.O_RDWR|os.O_CREATE|os.O_EXCL, 0666)
-		f.Close()
-		if errors.Is(err, fs.ErrExist) {
-			return _BUSY // Another process has the lock.
-		}
-		if err != nil {
+		if err := dotlk.TryLock(name + ".lock"); err != nil {
+			if errors.Is(err, fs.ErrExist) {
+				return _BUSY // Another process has the lock.
+			}
 			return _IOERR_LOCK
 		}
 		locker = &vfsDotLocker{}
@@ -114,8 +114,7 @@ func osReleaseLock(file *os.File, state LockLevel) _ErrorCode {
 	}

 	if locker.shared == 1 {
-		err := os.Remove(name + ".lock")
-		if err != nil && !errors.Is(err, fs.ErrNotExist) {
+		if err := dotlk.Unlock(name + ".lock"); err != nil {
 			return _IOERR_UNLOCK
 		}
 		delete(vfsDotLocks, name)
--- a/vfs/os_linux.go
+++ b/vfs/os_linux.go
@@ -3,7 +3,6 @@
 package vfs

 import (
-	"math/rand"
 	"os"
 	"time"

@@ -22,6 +21,30 @@ func osAllocate(file *os.File, size int64) error {
 	return unix.Fallocate(int(file.Fd()), 0, 0, size)
 }

+func osReadLock(file *os.File, start, len int64, timeout time.Duration) _ErrorCode {
+	return osLock(file, unix.F_RDLCK, start, len, timeout, _IOERR_RDLOCK)
+}
+
+func osWriteLock(file *os.File, start, len int64, timeout time.Duration) _ErrorCode {
+	return osLock(file, unix.F_WRLCK, start, len, timeout, _IOERR_LOCK)
+}
+
+func osLock(file *os.File, typ int16, start, len int64, timeout time.Duration, def _ErrorCode) _ErrorCode {
+	lock := unix.Flock_t{
+		Type:  typ,
+		Start: start,
+		Len:   len,
+	}
+	var err error
+	switch {
+	case timeout < 0:
+		err = unix.FcntlFlock(file.Fd(), unix.F_OFD_SETLKW, &lock)
+	default:
+		err = unix.FcntlFlock(file.Fd(), unix.F_OFD_SETLK, &lock)
+	}
+	return osLockErrorCode(err, def)
+}
+
 func osUnlock(file *os.File, start, len int64) _ErrorCode {
 	err := unix.FcntlFlock(file.Fd(), unix.F_OFD_SETLK, &unix.Flock_t{
 		Type:  unix.F_UNLCK,
@@ -33,40 +56,3 @@ func osUnlock(file *os.File, start, len int64) _ErrorCode {
 	}
 	return _OK
 }
-
-func osLock(file *os.File, typ int16, start, len int64, timeout time.Duration, def _ErrorCode) _ErrorCode {
-	lock := unix.Flock_t{
-		Type:  typ,
-		Start: start,
-		Len:   len,
-	}
-	var err error
-	switch {
-	case timeout == 0:
-		err = unix.FcntlFlock(file.Fd(), unix.F_OFD_SETLK, &lock)
-	case timeout < 0:
-		err = unix.FcntlFlock(file.Fd(), unix.F_OFD_SETLKW, &lock)
-	default:
-		before := time.Now()
-		for {
-			err = unix.FcntlFlock(file.Fd(), unix.F_OFD_SETLK, &lock)
-			if errno, _ := err.(unix.Errno); errno != unix.EAGAIN {
-				break
-			}
-			if time.Since(before) > timeout {
-				break
-			}
-			const sleepIncrement = 1024*1024 - 1 // power of two, ~1ms
-			time.Sleep(time.Duration(rand.Int63() & sleepIncrement))
-		}
-	}
-	return osLockErrorCode(err, def)
-}
-
-func osReadLock(file *os.File, start, len int64, timeout time.Duration) _ErrorCode {
-	return osLock(file, unix.F_RDLCK, start, len, timeout, _IOERR_RDLOCK)
-}
-
-func osWriteLock(file *os.File, start, len int64, timeout time.Duration) _ErrorCode {
-	return osLock(file, unix.F_WRLCK, start, len, timeout, _IOERR_LOCK)
-}
--- a/vfs/os_std.go
+++ b/vfs/os_std.go
@@ -7,7 +7,10 @@ import (
 	"os"
 )

-const _O_NOFOLLOW = 0
+const (
+	_O_NOFOLLOW = 0
+	canSyncDirs = false
+)

 func osAccess(path string, flags AccessFlag) error {
 	fi, err := os.Stat(path)
--- a/vfs/os_unix.go
+++ b/vfs/os_unix.go
@@ -9,7 +9,10 @@ import (
 	"golang.org/x/sys/unix"
 )

-const _O_NOFOLLOW = unix.O_NOFOLLOW
+const (
+	_O_NOFOLLOW = unix.O_NOFOLLOW
+	canSyncDirs = true
+)

 func osAccess(path string, flags AccessFlag) error {
 	var access uint32 // unix.F_OK
--- a/vfs/os_windows.go
+++ b/vfs/os_windows.go
@@ -45,6 +45,7 @@ func osGetExclusiveLock(file *os.File, state *LockLevel) _ErrorCode {
 	osUnlock(file, _SHARED_FIRST, _SHARED_SIZE)

 	// Acquire the EXCLUSIVE lock.
+	// Can't wait here, because the file is not OVERLAPPED.
 	rc := osWriteLock(file, _SHARED_FIRST, _SHARED_SIZE, 0)

 	if rc != _OK {
@@ -106,6 +107,27 @@ func osCheckReservedLock(file *os.File) (bool, _ErrorCode) {
 	return false, rc
 }

+func osReadLock(file *os.File, start, len uint32, timeout time.Duration) _ErrorCode {
+	return osLock(file, 0, start, len, timeout, _IOERR_RDLOCK)
+}
+
+func osWriteLock(file *os.File, start, len uint32, timeout time.Duration) _ErrorCode {
+	return osLock(file, windows.LOCKFILE_EXCLUSIVE_LOCK, start, len, timeout, _IOERR_LOCK)
+}
+
+func osLock(file *os.File, flags, start, len uint32, timeout time.Duration, def _ErrorCode) _ErrorCode {
+	var err error
+	switch {
+	case timeout == 0:
+		err = osLockEx(file, flags|windows.LOCKFILE_FAIL_IMMEDIATELY, start, len)
+	case timeout < 0:
+		err = osLockEx(file, flags, start, len)
+	default:
+		err = osLockExTimeout(file, flags, start, len, timeout)
+	}
+	return osLockErrorCode(err, def)
+}
+
 func osUnlock(file *os.File, start, len uint32) _ErrorCode {
 	err := windows.UnlockFileEx(windows.Handle(file.Fd()),
 		0, len, 0, &windows.Overlapped{Offset: start})
@@ -118,52 +140,40 @@ func osUnlock(file *os.File, start, len uint32) _ErrorCode {
 	return _OK
 }

-func osLock(file *os.File, flags, start, len uint32, timeout time.Duration, def _ErrorCode) _ErrorCode {
-	var err error
-	switch {
-	case timeout == 0:
-		err = osLockEx(file, flags|windows.LOCKFILE_FAIL_IMMEDIATELY, start, len, 0)
-	case timeout < 0:
-		err = osLockEx(file, flags, start, len, 0)
-	default:
-		var event windows.Handle
-		event, err = windows.CreateEvent(nil, 1, 0, nil)
-		if err != nil {
-			break
-		}
-		defer windows.CloseHandle(event)
-
-		err = osLockEx(file, flags, start, len, event)
-		if err == windows.ERROR_IO_PENDING {
-			rc, serr := windows.WaitForSingleObject(event, uint32(timeout/time.Millisecond))
-			if rc == windows.WAIT_OBJECT_0 {
-				return _OK
-			}
-			if serr != nil {
-				err = serr
-			} else {
-				err = windows.Errno(rc)
-			}
-			windows.CancelIo(windows.Handle(file.Fd()))
-		}
-	}
-	return osLockErrorCode(err, def)
-}
-
-func osLockEx(file *os.File, flags, start, len uint32, event windows.Handle) error {
+func osLockEx(file *os.File, flags, start, len uint32) error {
 	return windows.LockFileEx(windows.Handle(file.Fd()), flags,
-		0, len, 0, &windows.Overlapped{
-			Offset: start,
-			HEvent: event,
-		})
+		0, len, 0, &windows.Overlapped{Offset: start})
 }

-func osReadLock(file *os.File, start, len uint32, timeout time.Duration) _ErrorCode {
-	return osLock(file, 0, start, len, timeout, _IOERR_RDLOCK)
-}
+func osLockExTimeout(file *os.File, flags, start, len uint32, timeout time.Duration) error {
+	event, err := windows.CreateEvent(nil, 1, 0, nil)
+	if err != nil {
+		return err
+	}
+	defer windows.CloseHandle(event)

-func osWriteLock(file *os.File, start, len uint32, timeout time.Duration) _ErrorCode {
-	return osLock(file, windows.LOCKFILE_EXCLUSIVE_LOCK, start, len, timeout, _IOERR_LOCK)
+	fd := windows.Handle(file.Fd())
+	overlapped := &windows.Overlapped{
+		Offset: start,
+		HEvent: event,
+	}
+
+	err = windows.LockFileEx(fd, flags, 0, len, 0, overlapped)
+	if err != windows.ERROR_IO_PENDING {
+		return err
+	}
+
+	ms := (timeout + time.Millisecond - 1) / time.Millisecond
+	rc, err := windows.WaitForSingleObject(event, uint32(ms))
+	if rc == windows.WAIT_OBJECT_0 {
+		return nil
+	}
+	defer windows.CancelIoEx(fd, overlapped)
+
+	if err != nil {
+		return err
+	}
+	return windows.Errno(rc)
 }

 func osLockErrorCode(err error, def _ErrorCode) _ErrorCode {
@@ -175,8 +185,8 @@ func osLockErrorCode(err error, def _ErrorCode) _ErrorCode {
 		switch errno {
 		case
 			windows.ERROR_LOCK_VIOLATION,
-			windows.ERROR_IO_PENDING,
 			windows.ERROR_OPERATION_ABORTED,
+			windows.ERROR_IO_PENDING,
 			windows.WAIT_TIMEOUT:
 			return _BUSY
 		}
--- a/vfs/shm_bsd.go
+++ b/vfs/shm_bsd.go
@@ -4,7 +4,9 @@ package vfs

 import (
 	"context"
+	"errors"
 	"io"
+	"io/fs"
 	"os"
 	"sync"

@@ -20,7 +22,7 @@ type vfsShmParent struct {

 	refs int // +checklocks:vfsShmListMtx

-	lock [_SHM_NLOCK]int16 // +checklocks:Mutex
+	lock [_SHM_NLOCK]int8 // +checklocks:Mutex
 	sync.Mutex
 }

@@ -71,23 +73,21 @@ func (s *vfsShm) shmOpen() _ErrorCode {
 		return _OK
 	}

-	// Always open file read-write, as it will be shared.
-	f, err := os.OpenFile(s.path,
-		os.O_RDWR|os.O_CREATE|_O_NOFOLLOW, 0666)
-	if err != nil {
-		return _CANTOPEN
-	}
-	// Closes file if it's not nil.
+	var f *os.File
+	// Close file on error.
+	// Keep this here to avoid confusing checklocks.
 	defer func() { f.Close() }()

-	fi, err := f.Stat()
-	if err != nil {
-		return _IOERR_FSTAT
-	}
-
 	vfsShmListMtx.Lock()
 	defer vfsShmListMtx.Unlock()

+	// Stat file without opening it.
+	// Closing it would release all POSIX locks on it.
+	fi, err := os.Stat(s.path)
+	if err != nil && !errors.Is(err, fs.ErrNotExist) {
+		return _IOERR_FSTAT
+	}
+
 	// Find a shared file, increase the reference count.
 	for _, g := range vfsShmList {
 		if g != nil && os.SameFile(fi, g.info) {
@@ -97,13 +97,33 @@ func (s *vfsShm) shmOpen() _ErrorCode {
 		}
 	}

-	// Lock and truncate the file.
-	// The lock is only released by closing the file.
-	if rc := osLock(f, unix.LOCK_EX|unix.LOCK_NB, _IOERR_LOCK); rc != _OK {
+	// Always open file read-write, as it will be shared.
+	f, err = os.OpenFile(s.path,
+		os.O_RDWR|os.O_CREATE|_O_NOFOLLOW, 0666)
+	if err != nil {
+		return _CANTOPEN
+	}
+
+	// Dead man's switch.
+	if lock, rc := osTestLock(f, _SHM_DMS, 1); rc != _OK {
+		return _IOERR_LOCK
+	} else if lock == unix.F_WRLCK {
+		return _BUSY
+	} else if lock == unix.F_UNLCK {
+		if rc := osWriteLock(f, _SHM_DMS, 1); rc != _OK {
+			return rc
+		}
+		if err := f.Truncate(0); err != nil {
+			return _IOERR_SHMOPEN
+		}
+	}
+	if rc := osReadLock(f, _SHM_DMS, 1); rc != _OK {
 		return rc
 	}
-	if err := f.Truncate(0); err != nil {
-		return _IOERR_SHMOPEN
+
+	fi, err = f.Stat()
+	if err != nil {
+		return _IOERR_FSTAT
 	}

 	// Add the new shared file.
@@ -157,7 +177,52 @@ func (s *vfsShm) shmMap(ctx context.Context, mod api.Module, id, size int32, ext
 func (s *vfsShm) shmLock(offset, n int32, flags _ShmFlag) _ErrorCode {
 	s.Lock()
 	defer s.Unlock()
-	return s.shmMemLock(offset, n, flags)
+
+	// Check if we can obtain/release locks locally.
+	rc := s.shmMemLock(offset, n, flags)
+	if rc != _OK {
+		return rc
+	}
+
+	// Obtain/release the appropriate file locks.
+	switch {
+	case flags&_SHM_UNLOCK != 0:
+		// Relasing a shared lock decrements the counter,
+		// but may leave parts of the range still locked.
+		begin, end := offset, offset+n
+		for i := begin; i < end; i++ {
+			if s.vfsShmParent.lock[i] != 0 {
+				if i > begin {
+					rc |= osUnlock(s.File, _SHM_BASE+int64(begin), int64(i-begin))
+				}
+				begin = i + 1
+			}
+		}
+		if end > begin {
+			rc |= osUnlock(s.File, _SHM_BASE+int64(begin), int64(end-begin))
+		}
+		return rc
+	case flags&_SHM_SHARED != 0:
+		// Acquiring a new shared lock on the file is only necessary
+		// if there was a new shared lock in the range.
+		for i := offset; i < offset+n; i++ {
+			if s.vfsShmParent.lock[i] == 1 {
+				rc = osReadLock(s.File, _SHM_BASE+int64(offset), int64(n))
+				break
+			}
+		}
+	case flags&_SHM_EXCLUSIVE != 0:
+		// Acquiring an exclusive lock on the file is always necessary.
+		rc = osWriteLock(s.File, _SHM_BASE+int64(offset), int64(n))
+	default:
+		panic(util.AssertErr())
+	}
+
+	// Release the local locks we had acquired.
+	if rc != _OK {
+		s.shmMemLock(offset, n, flags^(_SHM_UNLOCK|_SHM_LOCK))
+	}
+	return rc
 }

 func (s *vfsShm) shmUnmap(delete bool) {
--- a/vfs/shm_dotlk.go
+++ b/vfs/shm_dotlk.go
@@ -6,11 +6,11 @@ import (
 	"context"
 	"errors"
 	"io/fs"
-	"os"
 	"sync"

 	"github.com/tetratelabs/wazero/api"

+	"github.com/ncruces/go-sqlite3/internal/dotlk"
 	"github.com/ncruces/go-sqlite3/internal/util"
 )

@@ -18,7 +18,7 @@ type vfsShmParent struct {
 	shared [][_WALINDEX_PGSZ]byte
 	refs   int // +checklocks:vfsShmListMtx

-	lock [_SHM_NLOCK]int16 // +checklocks:Mutex
+	lock [_SHM_NLOCK]int8 // +checklocks:Mutex
 	sync.Mutex
 }

@@ -58,8 +58,7 @@ func (s *vfsShm) Close() error {
 		return nil
 	}

-	err := os.Remove(s.path)
-	if err != nil && !errors.Is(err, fs.ErrNotExist) {
+	if err := dotlk.Unlock(s.path); err != nil {
 		return _IOERR_UNLOCK
 	}
 	delete(vfsShmList, s.path)
@@ -82,9 +81,8 @@ func (s *vfsShm) shmOpen() _ErrorCode {
 		return _OK
 	}

-	// Create a directory on disk to ensure only this process
-	// uses this path to register a shared memory.
-	err := os.Mkdir(s.path, 0777)
+	// Dead man's switch.
+	err := dotlk.LockShm(s.path)
 	if errors.Is(err, fs.ErrExist) {
 		return _BUSY
 	}
--- a/vfs/shm_memlk.go
+++ b/vfs/shm_memlk.go
@@ -10,9 +10,6 @@ func (s *vfsShm) shmMemLock(offset, n int32, flags _ShmFlag) _ErrorCode {
 	case flags&_SHM_UNLOCK != 0:
 		for i := offset; i < offset+n; i++ {
 			if s.lock[i] {
-				if s.vfsShmParent.lock[i] == 0 {
-					panic(util.AssertErr())
-				}
 				if s.vfsShmParent.lock[i] <= 0 {
 					s.vfsShmParent.lock[i] = 0
 				} else {
@@ -23,20 +20,21 @@ func (s *vfsShm) shmMemLock(offset, n int32, flags _ShmFlag) _ErrorCode {
 		}
 	case flags&_SHM_SHARED != 0:
 		for i := offset; i < offset+n; i++ {
-			if s.lock[i] {
-				panic(util.AssertErr())
-			}
-			if s.vfsShmParent.lock[i]+1 <= 0 {
+			if !s.lock[i] &&
+				s.vfsShmParent.lock[i]+1 <= 0 {
 				return _BUSY
 			}
 		}
 		for i := offset; i < offset+n; i++ {
-			s.vfsShmParent.lock[i]++
-			s.lock[i] = true
+			if !s.lock[i] {
+				s.vfsShmParent.lock[i]++
+				s.lock[i] = true
+			}
 		}
 	case flags&_SHM_EXCLUSIVE != 0:
 		for i := offset; i < offset+n; i++ {
 			if s.lock[i] {
+				// SQLite never requests an exclusive lock that it already holds.
 				panic(util.AssertErr())
 			}
 			if s.vfsShmParent.lock[i] != 0 {
--- a/vfs/shm_ofd.go
+++ b/vfs/shm_ofd.go
@@ -110,7 +110,12 @@ func (s *vfsShm) shmMap(ctx context.Context, mod api.Module, id, size int32, ext

 func (s *vfsShm) shmLock(offset, n int32, flags _ShmFlag) _ErrorCode {
 	// Argument check.
-	if n <= 0 || offset < 0 || offset+n > _SHM_NLOCK {
+	switch {
+	case n <= 0:
+		panic(util.AssertErr())
+	case offset < 0 || offset+n > _SHM_NLOCK:
+		panic(util.AssertErr())
+	case n != 1 && flags&_SHM_EXCLUSIVE == 0:
 		panic(util.AssertErr())
 	}
 	switch flags {
@@ -123,9 +128,6 @@ func (s *vfsShm) shmLock(offset, n int32, flags _ShmFlag) _ErrorCode {
 	default:
 		panic(util.AssertErr())
 	}
-	if n != 1 && flags&_SHM_EXCLUSIVE == 0 {
-		panic(util.AssertErr())
-	}

 	var timeout time.Duration
 	if s.blocking {
--- a/vfs/tests/mptest/mptest_test.go
+++ b/vfs/tests/mptest/mptest_test.go
@@ -2,7 +2,6 @@ package mptest

 import (
 	"bytes"
-	"compress/bzip2"
 	"context"
 	"crypto/rand"
 	"embed"
@@ -29,14 +28,9 @@ import (
 	_ "github.com/ncruces/go-sqlite3/vfs/xts"
 )

-//go:embed testdata/mptest.wasm.bz2
-var compressed string
-
-//go:embed testdata/*.*test
+//go:embed testdata/*
 var scripts embed.FS

-const qemuCI = runtime.GOARCH != "386" && runtime.GOARCH != "amd64" && runtime.GOARCH != "arm64"
-
 var (
 	rt        wazero.Runtime
 	module    wazero.CompiledModule
@@ -57,10 +51,7 @@ func TestMain(m *testing.M) {
 		panic(err)
 	}

-	if !strings.HasPrefix(compressed, "BZh") {
-		panic("Please use Git LFS to clone this repo: https://git-lfs.com/")
-	}
-	binary, err := io.ReadAll(bzip2.NewReader(strings.NewReader(compressed)))
+	binary, err := os.ReadFile("wasm/mptest.wasm")
 	if err != nil {
 		panic(err)
 	}
@@ -162,8 +153,8 @@ func Test_crash01(t *testing.T) {
 }

 func Test_multiwrite01(t *testing.T) {
-	if os.Getenv("CI") != "" && qemuCI {
-		t.Skip("skipping in CI")
+	if testing.Short() && os.Getenv("CI") != "" {
+		t.Skip("skipping in slow CI")
 	}
 	if !vfs.SupportsFileLocking {
 		t.Skip("skipping without locks")
@@ -192,8 +183,8 @@ func Test_config01_memory(t *testing.T) {
 }

 func Test_multiwrite01_memory(t *testing.T) {
-	if os.Getenv("CI") != "" && qemuCI {
-		t.Skip("skipping in CI")
+	if testing.Short() && os.Getenv("CI") != "" {
+		t.Skip("skipping in slow CI")
 	}

 	memdb.Create("test.db", nil)
@@ -227,8 +218,8 @@ func Test_crash01_wal(t *testing.T) {
 }

 func Test_multiwrite01_wal(t *testing.T) {
-	if os.Getenv("CI") != "" && qemuCI {
-		t.Skip("skipping in CI")
+	if testing.Short() && os.Getenv("CI") != "" {
+		t.Skip("skipping in slow CI")
 	}
 	if !vfs.SupportsSharedMemory {
 		t.Skip("skipping without shared memory")
--- a/vfs/tests/mptest/testdata/.gitattributes
+++ b/vfs/tests/mptest/testdata/.gitattributes
@@ -1,2 +1 @@
-mptest.wasm.bz2 filter=lfs diff=lfs merge=lfs -text
-*.*test -crlf
+* -crlf
--- a/vfs/tests/mptest/testdata/mptest.wasm.bz2
+++ b/vfs/tests/mptest/testdata/mptest.wasm.bz2
@@ -1,3 +0,0 @@
-version https://git-lfs.github.com/spec/v1
-oid sha256:da52d62d7ccd9d203eaa6d281a8a61786f99b772b6de3c31c633e6a480e80df9
-size 480698
--- a/vfs/tests/mptest/testdata/.gitignore
+++ b/vfs/tests/mptest/testdata/.gitignore
--- a/vfs/tests/mptest/testdata/build.sh
+++ b/vfs/tests/mptest/testdata/build.sh
@@ -10,7 +10,7 @@ WASI_SDK="$ROOT/tools/wasi-sdk/bin"
 "$WASI_SDK/clang" --target=wasm32-wasi -std=c23 -g0 -O2 \
 	-o mptest.wasm main.c \
 	-I"$ROOT/sqlite3" \
-	-matomics -msimd128 -mmutable-globals -mmultivalue \
+	-msimd128 -mmutable-globals -mmultivalue \
 	-mbulk-memory -mreference-types \
 	-mnontrapping-fptoint -msign-ext \
 	-fno-stack-protector -fno-stack-clash-protection \
@@ -30,5 +30,4 @@ WASI_SDK="$ROOT/tools/wasi-sdk/bin"
 	--enable-simd --enable-mutable-globals --enable-multivalue \
 	--enable-bulk-memory --enable-reference-types \
 	--enable-nontrapping-float-to-int --enable-sign-ext
-mv mptest.tmp mptest.wasm
-bzip2 -9f mptest.wasm
+mv mptest.tmp mptest.wasm
--- a/vfs/tests/mptest/testdata/exports.txt
+++ b/vfs/tests/mptest/testdata/exports.txt
--- a/vfs/tests/mptest/wasm/go.mod
+++ b/vfs/tests/mptest/wasm/go.mod
--- a/vfs/tests/mptest/testdata/main.c
+++ b/vfs/tests/mptest/testdata/main.c
--- a/vfs/tests/mptest/wasm/mptest.wasm
+++ b/vfs/tests/mptest/wasm/mptest.wasm
--- a/vfs/tests/speedtest1/speedtest1_test.go
+++ b/vfs/tests/speedtest1/speedtest1_test.go
@@ -2,7 +2,6 @@ package speedtest1

 import (
 	"bytes"
-	"compress/bzip2"
 	"context"
 	"crypto/rand"
 	_ "embed"
@@ -27,9 +26,6 @@ import (
 	_ "github.com/ncruces/go-sqlite3/vfs/xts"
 )

-//go:embed testdata/speedtest1.wasm.bz2
-var compressed string
-
 var (
 	rt      wazero.Runtime
 	module  wazero.CompiledModule
@@ -52,10 +48,7 @@ func TestMain(m *testing.M) {
 		panic(err)
 	}

-	if !strings.HasPrefix(compressed, "BZh") {
-		panic("Please use Git LFS to clone this repo: https://git-lfs.com/")
-	}
-	binary, err := io.ReadAll(bzip2.NewReader(strings.NewReader(compressed)))
+	binary, err := os.ReadFile("wasm/speedtest1.wasm")
 	if err != nil {
 		panic(err)
 	}
--- a/vfs/tests/speedtest1/testdata/.gitattributes
+++ b/vfs/tests/speedtest1/testdata/.gitattributes
@@ -1 +0,0 @@
-speedtest1.wasm.bz2 filter=lfs diff=lfs merge=lfs -text
--- a/Show More
+++ b/Show More
Author	SHA1	Message	Date
Nuno Cruces	d9b37307e7	SQLite 3.48.0.	2025-01-14 17:33:53 +00:00
Nuno Cruces	3bae1d7d4b	SQLITE_FCNTL_BUSYHANDLER.	2025-01-14 17:09:54 +00:00
Nuno Cruces	8887036c20	SQLITE_FCNTL_SYNC.	2025-01-14 10:05:54 +00:00
Nuno Cruces	ccb3dcd097	SQLITE_FCNTL_PDB.	2025-01-13 13:45:41 +00:00
Nuno Cruces	a9f33cc2b0	New constants.	2025-01-13 12:05:27 +00:00
Nuno Cruces	f025ffb385	Fix naming.	2025-01-13 09:28:47 +00:00
Nuno Cruces	aa4357a78f	Ordered-set aggregate syntax.	2025-01-11 19:22:04 +00:00
Nuno Cruces	aef7f051a8	Prevent modification.	2025-01-10 12:38:11 +00:00
Nuno Cruces	a79ee4c2c6	Avoid weird mutex.	2025-01-09 13:44:29 +00:00
Nuno Cruces	7424747338	Update README.md	2025-01-08 23:16:25 +00:00
Nuno Cruces	11830e05a6	Remove legacy.	2025-01-08 18:34:48 +00:00
Nuno Cruces	7dc4520690	Fix #207 .	2025-01-08 16:36:41 +00:00
Nuno Cruces	0c09dd89c2	Add wasmtime to CI. (#212 )	2025-01-07 16:31:12 +00:00
Nuno Cruces	31c5000875	Updated GORM driver. Fixes https://github.com/go-gorm/sqlite/issues/192.	2025-01-07 12:29:16 +00:00
Nuno Cruces	8175407754	Enable compiler on ARMv8. (#211 )	2025-01-06 18:22:36 +00:00
Nuno Cruces	abfad02d95	Remove LFS test files. (#210 )	2025-01-06 11:44:08 +00:00
Nuno Cruces	f7c3fb8062	Lines delimiter.	2025-01-05 19:35:07 +00:00
Nuno Cruces	c3633dda35	Update test.yml	2024-12-21 12:13:45 +00:00
Nuno Cruces	f2d894194d	Avoid syscall.	2024-12-21 10:16:23 +00:00
Nuno Cruces	e08c7b3adf	Refactor.	2024-12-19 15:14:20 +00:00
Nuno Cruces	66601dd3cb	More BCE.	2024-12-19 14:00:46 +00:00
Nuno Cruces	58b66b75f1	Improved assertions.	2024-12-19 13:19:10 +00:00
Nuno Cruces	e0c6086aa9	Fix POSIX locks.	2024-12-18 16:21:24 +00:00
Nuno Cruces	9bc39c5b91	Remove dependency.	2024-12-17 15:43:19 +00:00
Nuno Cruces	12193cedea	binaryen-version_121.	2024-12-17 15:25:25 +00:00
Nuno Cruces	71d95bf9d5	Fix #205 .	2024-12-17 14:21:56 +00:00
Nuno Cruces	7e23100ff7	Help checklocks.	2024-12-16 13:47:59 +00:00
Nuno Cruces	e32d8401fb	Improve Wal locking on BSD (#204 )	2024-12-16 13:15:00 +00:00
Nuno Cruces	503db60927	Fix repro.sh.	2024-12-13 16:22:44 +00:00
Nuno Cruces	1227fa7a04	Skip sleeping if blocked.	2024-12-13 16:04:37 +00:00
Nuno Cruces	e455b5f729	Coverage.	2024-12-13 10:30:08 +00:00
Nuno Cruces	2bb1c8c795	Fair retry interval.	2024-12-13 10:23:43 +00:00
Nuno Cruces	844fab4167	Fix fuzzer.	2024-12-12 13:38:46 +00:00
Nuno Cruces	5ed4a6cb9d	Fix #201 .	2024-12-12 12:57:18 +00:00
Nuno Cruces	37f2145588	Use CancelIoEx.	2024-12-12 10:42:23 +00:00
Nuno Cruces	e17b3ef2c8	wasi-sdk-25.	2024-12-12 09:51:23 +00:00
				`@@ -1 +0,0 @@`
				`speedtest1.wasm.bz2 filter=lfs diff=lfs merge=lfs -text`