diff --git a/_example/limit/limit.go b/_example/limit/limit.go new file mode 100644 index 0000000..4e4b897 --- /dev/null +++ b/_example/limit/limit.go @@ -0,0 +1,113 @@ +package main + +import ( + "database/sql" + "fmt" + "log" + "os" + "strings" + + "github.com/mattn/go-sqlite3" +) + +func createBulkInsertQuery(n int, start int) (query string, args []interface{}) { + values := make([]string, n) + args = make([]interface{}, n*2) + pos := 0 + for i := 0; i < n; i++ { + values[i] = "(?, ?)" + args[pos] = start + i + args[pos+1] = fmt.Sprintf("こんにちわ世界%03d", i) + pos += 2 + } + query = fmt.Sprintf( + "insert into foo(id, name) values %s", + strings.Join(values, ", "), + ) + return +} + +func bukInsert(db *sql.DB, query string, args []interface{}) (err error) { + stmt, err := db.Prepare(query) + if err != nil { + return + } + + _, err = stmt.Exec(args...) + if err != nil { + return + } + + return +} + +func main() { + var sqlite3conn *sqlite3.SQLiteConn + sql.Register("sqlite3_with_limit", &sqlite3.SQLiteDriver{ + ConnectHook: func(conn *sqlite3.SQLiteConn) error { + sqlite3conn = conn + return nil + }, + }) + + os.Remove("./foo.db") + db, err := sql.Open("sqlite3_with_limit", "./foo.db") + if err != nil { + log.Fatal(err) + } + defer db.Close() + + sqlStmt := ` + create table foo (id integer not null primary key, name text); + delete from foo; + ` + _, err = db.Exec(sqlStmt) + if err != nil { + log.Printf("%q: %s\n", err, sqlStmt) + return + } + + if sqlite3conn == nil { + log.Fatal("not set sqlite3 connection") + } + + limitVariableNumber := sqlite3conn.GetLimit(sqlite3.SQLITE_LIMIT_VARIABLE_NUMBER) + log.Printf("default SQLITE_LIMIT_VARIABLE_NUMBER: %d", limitVariableNumber) + + num := 400 + query, args := createBulkInsertQuery(num, 0) + err = bukInsert(db, query, args) + if err != nil { + log.Fatal(err) + } + + smallLimitVariableNumber := 100 + sqlite3conn.SetLimit(sqlite3.SQLITE_LIMIT_VARIABLE_NUMBER, smallLimitVariableNumber) + + limitVariableNumber = sqlite3conn.GetLimit(sqlite3.SQLITE_LIMIT_VARIABLE_NUMBER) + log.Printf("updated SQLITE_LIMIT_VARIABLE_NUMBER: %d", limitVariableNumber) + + query, args = createBulkInsertQuery(num, num) + err = bukInsert(db, query, args) + if err != nil { + if err != nil { + log.Printf("expect failed since SQLITE_LIMIT_VARIABLE_NUMBER is too small: %v", err) + } + } + + bigLimitVariableNumber := 999999 + sqlite3conn.SetLimit(sqlite3.SQLITE_LIMIT_VARIABLE_NUMBER, bigLimitVariableNumber) + limitVariableNumber = sqlite3conn.GetLimit(sqlite3.SQLITE_LIMIT_VARIABLE_NUMBER) + log.Printf("set SQLITE_LIMIT_VARIABLE_NUMBER: %d", bigLimitVariableNumber) + log.Printf("updated SQLITE_LIMIT_VARIABLE_NUMBER: %d", limitVariableNumber) + + query, args = createBulkInsertQuery(500, num+num) + err = bukInsert(db, query, args) + if err != nil { + if err != nil { + log.Fatal(err) + } + } + + log.Println("no error if SQLITE_LIMIT_VARIABLE_NUMBER > 999") +} diff --git a/sqlite3.go b/sqlite3.go index 1ff58c3..bcb6da0 100644 --- a/sqlite3.go +++ b/sqlite3.go @@ -827,6 +827,36 @@ func (c *SQLiteConn) prepare(ctx context.Context, query string) (driver.Stmt, er return ss, nil } +// Run-Time Limit Categories. +// See: http://www.sqlite.org/c3ref/c_limit_attached.html +const ( + SQLITE_LIMIT_LENGTH = C.SQLITE_LIMIT_LENGTH + SQLITE_LIMIT_SQL_LENGTH = C.SQLITE_LIMIT_SQL_LENGTH + SQLITE_LIMIT_COLUMN = C.SQLITE_LIMIT_COLUMN + SQLITE_LIMIT_EXPR_DEPTH = C.SQLITE_LIMIT_EXPR_DEPTH + SQLITE_LIMIT_COMPOUND_SELECT = C.SQLITE_LIMIT_COMPOUND_SELECT + SQLITE_LIMIT_VDBE_OP = C.SQLITE_LIMIT_VDBE_OP + SQLITE_LIMIT_FUNCTION_ARG = C.SQLITE_LIMIT_FUNCTION_ARG + SQLITE_LIMIT_ATTACHED = C.SQLITE_LIMIT_ATTACHED + SQLITE_LIMIT_LIKE_PATTERN_LENGTH = C.SQLITE_LIMIT_LIKE_PATTERN_LENGTH + SQLITE_LIMIT_VARIABLE_NUMBER = C.SQLITE_LIMIT_VARIABLE_NUMBER + SQLITE_LIMIT_TRIGGER_DEPTH = C.SQLITE_LIMIT_TRIGGER_DEPTH + SQLITE_LIMIT_WORKER_THREADS = C.SQLITE_LIMIT_WORKER_THREADS +) + +// GetLimit returns the current value of a run-time limit. +// See: sqlite3_limit, http://www.sqlite.org/c3ref/limit.html +func (c *SQLiteConn) GetLimit(id int) int { + return int(C.sqlite3_limit(c.db, C.int(id), -1)) +} + +// SetLimit changes the value of a run-time limits. +// Then this method returns the prior value of the limit. +// See: sqlite3_limit, http://www.sqlite.org/c3ref/limit.html +func (c *SQLiteConn) SetLimit(id int, newVal int) int { + return int(C.sqlite3_limit(c.db, C.int(id), C.int(newVal))) +} + // Close the statement. func (s *SQLiteStmt) Close() error { s.mu.Lock()