Busy handlers.

conn.go

@@ -4,8 +4,10 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"math"
 	"net/url"
 	"strings"
+	"time"
 
 	"github.com/ncruces/go-sqlite3/internal/util"
 	"github.com/tetratelabs/wazero/api"
@@ -20,6 +22,7 @@ type Conn struct {
 
 	interrupt  context.Context
 	pending    *Stmt
+	busy       func(int) bool
 	log        func(xErrorCode, string)
 	collation  func(*Conn, string)
 	authorizer func(AuthorizerActionCode, string, string, string, string) AuthorizerReturnCode
@@ -322,15 +325,49 @@ func (c *Conn) checkInterrupt() {
 	}
 }
 
-func progressCallback(ctx context.Context, mod api.Module, _ uint32) uint32 {
-	if c, ok := ctx.Value(connKey{}).(*Conn); ok {
+func progressCallback(ctx context.Context, mod api.Module, pDB uint32) uint32 {
+	if c, ok := ctx.Value(connKey{}).(*Conn); ok && c.handle == pDB && c.commit != nil {
 		if c.interrupt != nil && c.interrupt.Err() != nil {
 			return 1
 		}
 	}
 	return 0
 }
 
+// BusyTimeout sets a busy timeout.
+//
+// https://sqlite.org/c3ref/busy_timeout.html
+func (c *Conn) BusyTimeout(timeout time.Duration) error {
+	ms := min((timeout+time.Millisecond-1)/time.Millisecond, math.MaxInt32)
+	r := c.call("sqlite3_busy_timeout", uint64(c.handle), uint64(ms))
+	return c.error(r)
+}
+
+// BusyHandler registers a callback to handle [BUSY] errors.
+//
+// https://sqlite.org/c3ref/busy_handler.html
+func (c *Conn) BusyHandler(cb func(count int) (retry bool)) error {
+	var enable uint64
+	if cb != nil {
+		enable = 1
+	}
+	r := c.call("sqlite3_busy_handler_go", uint64(c.handle), enable)
+	if err := c.error(r); err != nil {
+		return err
+	}
+	c.busy = cb
+	return nil
+}
+
+func busyCallback(ctx context.Context, mod api.Module, pDB, count uint32) uint32 {
+	if c, ok := ctx.Value(connKey{}).(*Conn); ok && c.handle == pDB && c.busy != nil {
+		if retry := c.busy(int(count)); retry {
+			return 1
+		}
+	}
+	return 0
+}
+
 // Deprecated: executes a PRAGMA statement and returns results.
 func (c *Conn) Pragma(str string) ([]string, error) {
 	stmt, _, err := c.Prepare(`PRAGMA ` + str)

driver/driver.go

@@ -170,7 +170,7 @@ func (n *connector) Connect(ctx context.Context) (_ driver.Conn, err error) {
 	defer c.Conn.SetInterrupt(old)
 
 	if !n.pragmas {
-		err = c.Conn.Exec(`PRAGMA busy_timeout=60000`)
+		err = c.Conn.BusyTimeout(60 * time.Second)
 		if err != nil {
 			return nil, err
 		}

embed/exports.txt

@@ -24,6 +24,8 @@ sqlite3_blob_open
 sqlite3_blob_read
 sqlite3_blob_reopen
 sqlite3_blob_write
+sqlite3_busy_handler_go
+sqlite3_busy_timeout
 sqlite3_changes64
 sqlite3_clear_bindings
 sqlite3_close

sqlite.go

@@ -289,7 +289,8 @@ func (a *arena) string(s string) uint32 {
 }
 
 func exportCallbacks(env wazero.HostModuleBuilder) wazero.HostModuleBuilder {
-	util.ExportFuncII(env, "go_progress", progressCallback)
+	util.ExportFuncIII(env, "go_busy_handler", busyCallback)
+	util.ExportFuncII(env, "go_progress_handler", progressCallback)
 	util.ExportFuncII(env, "go_commit_hook", commitCallback)
 	util.ExportFuncVI(env, "go_rollback_hook", rollbackCallback)
 	util.ExportFuncVIIIIJ(env, "go_update_hook", updateCallback)

sqlite3/hooks.c

@@ -2,7 +2,8 @@
 
 #include "sqlite3.h"
 
-int go_progress(void *);
+int go_progress_handler(void *);
+int go_busy_handler(void *, int);
 
 int go_commit_hook(void *);
 void go_rollback_hook(void *);
@@ -14,7 +15,11 @@ int go_authorizer(void *, int, const char *, const char *, const char *,
 void go_log(void *, int, const char *);
 
 void sqlite3_progress_handler_go(sqlite3 *db, int n) {
-  sqlite3_progress_handler(db, n, go_progress, /*arg=*/db);
+  sqlite3_progress_handler(db, n, go_progress_handler, /*arg=*/db);
+}
+
+int sqlite3_busy_handler_go(sqlite3 *db, bool enable) {
+  return sqlite3_busy_handler(db, enable ? go_busy_handler : NULL, /*arg=*/db);
 }
 
 void sqlite3_commit_hook_go(sqlite3 *db, bool enable) {

tests/parallel/parallel_test.go

@@ -6,6 +6,7 @@ import (
 	"os/exec"
 	"path/filepath"
 	"testing"
+	"time"
 
 	"golang.org/x/sync/errgroup"
 
@@ -39,10 +40,7 @@ func TestMemory(t *testing.T) {
 		iter = 5000
 	}
 
-	name := "file:/test.db?vfs=memdb" +
-		"&_pragma=busy_timeout(10000)" +
-		"&_pragma=journal_mode(memory)" +
-		"&_pragma=synchronous(off)"
+	name := "file:/test.db?vfs=memdb"
 	testParallel(t, name, iter)
 	testIntegrity(t, name)
 }
@@ -100,10 +98,7 @@ func TestChildProcess(t *testing.T) {
 
 func BenchmarkMemory(b *testing.B) {
 	memdb.Delete("test.db")
-	name := "file:/test.db?vfs=memdb" +
-		"&_pragma=busy_timeout(10000)" +
-		"&_pragma=journal_mode(memory)" +
-		"&_pragma=synchronous(off)"
+	name := "file:/test.db?vfs=memdb"
 	testParallel(b, name, b.N)
 }
 
@@ -115,6 +110,14 @@ func testParallel(t testing.TB, name string, n int) {
 		}
 		defer db.Close()
 
+		err = db.BusyHandler(func(count int) (retry bool) {
+			time.Sleep(time.Millisecond)
+			return true
+		})
+		if err != nil {
+			return err
+		}
+
 		err = db.Exec(`CREATE TABLE IF NOT EXISTS users (id INT, name VARCHAR(10))`)
 		if err != nil {
 			return err
@@ -135,7 +138,7 @@ func testParallel(t testing.TB, name string, n int) {
 		}
 		defer db.Close()
 
-		err = db.Exec(`PRAGMA busy_timeout=10000`)
+		err = db.BusyTimeout(10 * time.Second)
 		if err != nil {
 			return err
 		}

txn.go

@@ -275,7 +275,7 @@ func (c *Conn) UpdateHook(cb func(action AuthorizerActionCode, schema, table str
 
 func commitCallback(ctx context.Context, mod api.Module, pDB uint32) uint32 {
 	if c, ok := ctx.Value(connKey{}).(*Conn); ok && c.handle == pDB && c.commit != nil {
-		if !c.commit() {
+		if ok := c.commit(); !ok {
 			return 1
 		}
 	}