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799 lines
19 KiB
Go
799 lines
19 KiB
Go
// Package db exposes a lightweight abstraction over the SQLite code.
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// It performs some basic mapping of lower-level types to rqlite types.
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package db
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import (
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"context"
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"database/sql"
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"expvar"
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"fmt"
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"io"
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"math/rand"
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"os"
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"strings"
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"time"
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"github.com/rqlite/go-sqlite3"
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"github.com/rqlite/rqlite/command"
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)
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const bkDelay = 250
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const (
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onDiskMaxOpenConns = 32
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onDiskMaxIdleTime = 120 * time.Second
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fkChecks = "PRAGMA foreign_keys"
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fkChecksEnabled = "PRAGMA foreign_keys=ON"
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fkChecksDisabled = "PRAGMA foreign_keys=OFF"
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journalCheck = "PRAGMA journal_mode"
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numExecutions = "executions"
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numExecutionErrors = "execution_errors"
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numQueries = "queries"
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numETx = "execute_transactions"
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numQTx = "query_transactions"
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)
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// DBVersion is the SQLite version.
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var DBVersion string
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// stats captures stats for the DB layer.
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var stats *expvar.Map
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func init() {
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DBVersion, _, _ = sqlite3.Version()
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stats = expvar.NewMap("db")
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stats.Add(numExecutions, 0)
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stats.Add(numExecutionErrors, 0)
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stats.Add(numQueries, 0)
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stats.Add(numETx, 0)
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stats.Add(numQTx, 0)
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}
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// DB is the SQL database.
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type DB struct {
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path string // Path to database file.
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memory bool // In-memory only.
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rwDB *sql.DB
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roDB *sql.DB
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}
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// PoolStats represents connection pool statistics
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type PoolStats struct {
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MaxOpenConnections int `json:"max_open_connections"`
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OpenConnections int `json:"open_connections"`
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InUse int `json:"in_use"`
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Idle int `json:"idle"`
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WaitCount int64 `json:"wait_count"`
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WaitDuration time.Duration `json:"wait_duration"`
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MaxIdleClosed int64 `json:"max_idle_closed"`
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MaxIdleTimeClosed int64 `json:"max_idle_time_closed"`
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MaxLifetimeClosed int64 `json:"max_lifetime_closed"`
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}
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// Result represents the outcome of an operation that changes rows.
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type Result struct {
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LastInsertID int64 `json:"last_insert_id,omitempty"`
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RowsAffected int64 `json:"rows_affected,omitempty"`
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Error string `json:"error,omitempty"`
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Time float64 `json:"time,omitempty"`
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}
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// Rows represents the outcome of an operation that returns query data.
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type Rows struct {
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Columns []string `json:"columns,omitempty"`
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Types []string `json:"types,omitempty"`
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Values [][]interface{} `json:"values,omitempty"`
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Error string `json:"error,omitempty"`
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Time float64 `json:"time,omitempty"`
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}
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// Open opens a file-based database, creating it if it does not exist.
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func Open(dbPath string) (*DB, error) {
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rwOpts := strings.Join(
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[]string{
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"mode=rw",
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}, "&")
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rwDB, err := sql.Open("sqlite3", fmt.Sprintf("file:%s?%s", dbPath, rwOpts))
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if err != nil {
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return nil, err
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}
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// XXX NOT SURE IF WAL WILL WORK. SIMPLY COPYING THE DATABASE FILE
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// WONT GET THE ENTIRE DATABASE. CAN WAL COMPACT BE FORCED?
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roOpts := strings.Join(
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[]string{
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"mode=ro",
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}, "&")
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roDB, err := sql.Open("sqlite3", fmt.Sprintf("file:%s?%s", dbPath, roOpts))
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if err != nil {
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return nil, err
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}
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// Set some reasonable connection pool behaviour.
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rwDB.SetConnMaxIdleTime(30 * time.Second)
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rwDB.SetConnMaxLifetime(0)
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roDB.SetConnMaxIdleTime(30 * time.Second)
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roDB.SetConnMaxLifetime(0)
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return &DB{
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path: dbPath,
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rwDB: rwDB,
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roDB: roDB,
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}, nil
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}
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// OpenInMemory returns a new in-memory database.
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func OpenInMemory() (*DB, error) {
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inMemPath := fmt.Sprintf("file:/%s", randomString())
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//rwDB, err := sql.Open("sqlite3", fmt.Sprintf("file:/%s?%s", inMemPath, rwOpts))
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rwDB, err := sql.Open("sqlite3", fmt.Sprintf("file:/%s?mode=rw&vfs=memdb&_txlock=immediate", inMemPath))
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if err != nil {
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return nil, err
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}
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// Ensure there is only one connection and it never closes.
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// If it closed, in-memory database could be lost.
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rwDB.SetConnMaxIdleTime(0)
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rwDB.SetConnMaxLifetime(0)
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rwDB.SetMaxIdleConns(1)
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rwDB.SetMaxOpenConns(1)
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roDB, err := sql.Open("sqlite3", fmt.Sprintf("file:/%s?mode=ro&vfs=memdb&_txlock=deferred", inMemPath))
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if err != nil {
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return nil, err
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}
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return &DB{
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rwDB: rwDB,
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roDB: roDB,
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}, nil
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}
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// LoadIntoMemory loads an in-memory database with that at the path.
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// Not safe to call while other operations are happening with the
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// source database.
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func LoadIntoMemory(dbPath string) (*DB, error) {
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dstDB, err := OpenInMemory()
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if err != nil {
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return nil, err
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}
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srcDB, err := Open(dbPath)
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if err != nil {
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return nil, err
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}
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if err := copyDatabase(dstDB, srcDB); err != nil {
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return nil, err
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}
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if err := srcDB.Close(); err != nil {
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return nil, err
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}
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return dstDB, nil
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}
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// DeserializeIntoMemory loads an in-memory database with that contained
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// in the byte slide. The byte slice must not be changed or garbage-collected
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// until after this function returns.
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func DeserializeIntoMemory(b []byte) (retDB *DB, retErr error) {
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// Get a plain-ol' in-memory database.
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tmpDB, err := sql.Open("sqlite3", ":memory:")
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if err != nil {
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return nil, fmt.Errorf("DeserializeIntoMemory: %s", err.Error())
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}
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defer tmpDB.Close()
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tmpConn, err := tmpDB.Conn(context.Background())
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if err != nil {
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return nil, err
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}
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// tmpDB will still be using memory in Go space, so tmpDB needs to be explicitly
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// copied to a new database, which we create now.
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db, err := OpenInMemory()
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if err != nil {
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return nil, fmt.Errorf("DeserializeIntoMemory: %s", err.Error())
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}
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defer func() {
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// Don't leak a database if deserialization fails.
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if retErr != nil {
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db.Close()
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}
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}()
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if err := tmpConn.Raw(func(driverConn interface{}) error {
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srcConn := driverConn.(*sqlite3.SQLiteConn)
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err2 := srcConn.Deserialize(b, "")
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if err2 != nil {
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return fmt.Errorf("DeserializeIntoMemory: %s", err.Error())
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}
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defer srcConn.Close()
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// Now copy from tmp database to the database this function will return.
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dbConn, err3 := db.rwDB.Conn(context.Background())
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if err3 != nil {
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return fmt.Errorf("DeserializeIntoMemory: %s", err.Error())
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}
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defer dbConn.Close()
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return dbConn.Raw(func(driverConn interface{}) error {
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dstConn := driverConn.(*sqlite3.SQLiteConn)
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return copyDatabaseConnection(dstConn, srcConn)
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})
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}); err != nil {
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return nil, err
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}
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return db, nil
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}
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// Close closes the underlying database connection.
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func (db *DB) Close() error {
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if err := db.rwDB.Close(); err != nil {
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return err
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}
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return db.roDB.Close()
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}
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// EnableFKConstraints allows control of foreign key constraint checks.
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func (db *DB) EnableFKConstraints(e bool) error {
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q := fkChecksEnabled
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if !e {
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q = fkChecksDisabled
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}
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_, err := db.ExecuteStringStmt(q)
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return err
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}
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// Size returns the size of the database in bytes. "Size" is defined as
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// page_count * schema.page_size.
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func (db *DB) Size() (int64, error) {
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query := `SELECT page_count * page_size as size FROM pragma_page_count(), pragma_page_size()`
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r, err := db.QueryStringStmt(query)
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if err != nil {
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return 0, err
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}
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return r[0].Values[0][0].(int64), nil
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}
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// FileSize returns the size of the SQLite file on disk. If running in
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// on-memory mode, this function returns 0.
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func (db *DB) FileSize() (int64, error) {
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if db.memory {
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return 0, nil
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}
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fi, err := os.Stat(db.path)
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if err != nil {
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return 0, err
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}
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return fi.Size(), nil
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}
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// ConnectionPoolStats returns database pool statistics
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func (db *DB) ConnectionPoolStats() *PoolStats {
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s := db.rwDB.Stats()
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return &PoolStats{
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MaxOpenConnections: s.MaxOpenConnections,
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OpenConnections: s.OpenConnections,
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InUse: s.InUse,
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Idle: s.Idle,
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WaitCount: s.WaitCount,
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WaitDuration: s.WaitDuration,
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MaxIdleClosed: s.MaxIdleClosed,
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MaxIdleTimeClosed: s.MaxIdleTimeClosed,
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MaxLifetimeClosed: s.MaxLifetimeClosed,
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}
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}
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// ExecuteStringStmt executes a single query that modifies the database. This is
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// primarily a convenience function.
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func (db *DB) ExecuteStringStmt(query string) ([]*Result, error) {
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r := &command.Request{
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Statements: []*command.Statement{
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{
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Sql: query,
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},
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},
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}
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return db.Execute(r, false)
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}
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// Execute executes queries that modify the database.
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func (db *DB) Execute(req *command.Request, xTime bool) ([]*Result, error) {
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stats.Add(numExecutions, int64(len(req.Statements)))
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conn, err := db.rwDB.Conn(context.Background())
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if err != nil {
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return nil, err
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}
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defer conn.Close()
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type Execer interface {
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ExecContext(ctx context.Context, query string, args ...interface{}) (sql.Result, error)
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}
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var execer Execer
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var tx *sql.Tx
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if req.Transaction {
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stats.Add(numETx, 1)
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tx, err = conn.BeginTx(context.Background(), nil)
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if err != nil {
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return nil, err
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}
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defer func() {
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if tx != nil {
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tx.Rollback() // Will be ignored if tx is committed
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}
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}()
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execer = tx
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} else {
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execer = conn
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}
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var allResults []*Result
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// handleError sets the error field on the given result. It returns
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// whether the caller should continue processing or break.
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handleError := func(result *Result, err error) bool {
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stats.Add(numExecutionErrors, 1)
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result.Error = err.Error()
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allResults = append(allResults, result)
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if tx != nil {
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tx.Rollback()
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tx = nil
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return false
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}
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return true
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}
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// Execute each statement.
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for _, stmt := range req.Statements {
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ss := stmt.Sql
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if ss == "" {
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continue
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}
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result := &Result{}
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start := time.Now()
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parameters, err := parametersToValues(stmt.Parameters)
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if err != nil {
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if handleError(result, err) {
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continue
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}
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break
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}
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r, err := execer.ExecContext(context.Background(), ss, parameters...)
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if err != nil {
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if handleError(result, err) {
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continue
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}
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break
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}
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if r == nil {
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continue
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}
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lid, err := r.LastInsertId()
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if err != nil {
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if handleError(result, err) {
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continue
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}
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break
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}
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result.LastInsertID = lid
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ra, err := r.RowsAffected()
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if err != nil {
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if handleError(result, err) {
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continue
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}
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break
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}
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result.RowsAffected = ra
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if xTime {
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result.Time = time.Now().Sub(start).Seconds()
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}
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allResults = append(allResults, result)
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}
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if tx != nil {
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err = tx.Commit()
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}
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return allResults, err
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}
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// QueryStringStmt executes a single query that return rows, but don't modify database.
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func (db *DB) QueryStringStmt(query string) ([]*Rows, error) {
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r := &command.Request{
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Statements: []*command.Statement{
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{
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Sql: query,
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},
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},
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}
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return db.Query(r, false)
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}
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// Query executes queries that return rows, but don't modify the database.
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func (db *DB) Query(req *command.Request, xTime bool) ([]*Rows, error) {
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stats.Add(numQueries, int64(len(req.Statements)))
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conn, err := db.roDB.Conn(context.Background())
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if err != nil {
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return nil, err
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}
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defer conn.Close()
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return db.queryWithConn(req, xTime, conn)
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}
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func (db *DB) queryWithConn(req *command.Request, xTime bool, conn *sql.Conn) ([]*Rows, error) {
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var err error
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type Queryer interface {
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QueryContext(ctx context.Context, query string, args ...interface{}) (*sql.Rows, error)
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}
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var queryer Queryer
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var tx *sql.Tx
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if req.Transaction {
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stats.Add(numQTx, 1)
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tx, err = conn.BeginTx(context.Background(), nil)
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if err != nil {
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return nil, err
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}
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defer tx.Rollback() // Will be ignored if tx is committed
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queryer = tx
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} else {
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queryer = conn
|
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}
|
|
|
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var allRows []*Rows
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for _, stmt := range req.Statements {
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sql := stmt.Sql
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if sql == "" {
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continue
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}
|
|
|
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rows := &Rows{}
|
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start := time.Now()
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|
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parameters, err := parametersToValues(stmt.Parameters)
|
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if err != nil {
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rows.Error = err.Error()
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allRows = append(allRows, rows)
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continue
|
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}
|
|
|
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rs, err := queryer.QueryContext(context.Background(), sql, parameters...)
|
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if err != nil {
|
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rows.Error = err.Error()
|
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allRows = append(allRows, rows)
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continue
|
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}
|
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defer rs.Close()
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|
|
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rows.Columns, err = rs.Columns()
|
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if err != nil {
|
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return nil, err
|
|
}
|
|
|
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types, err := rs.ColumnTypes()
|
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if err != nil {
|
|
return nil, err
|
|
}
|
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rows.Types = make([]string, len(types))
|
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for i := range types {
|
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rows.Types[i] = strings.ToLower(types[i].DatabaseTypeName())
|
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}
|
|
|
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for rs.Next() {
|
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dest := make([]interface{}, len(rows.Columns))
|
|
ptrs := make([]interface{}, len(dest))
|
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for i := range ptrs {
|
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ptrs[i] = &dest[i]
|
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}
|
|
if err := rs.Scan(ptrs...); err != nil {
|
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return nil, err
|
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}
|
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values := normalizeRowValues(dest, rows.Types)
|
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rows.Values = append(rows.Values, values)
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}
|
|
|
|
// Check for errors from iterating over rows.
|
|
if err := rs.Err(); err != nil {
|
|
return nil, err
|
|
}
|
|
|
|
if xTime {
|
|
rows.Time = time.Now().Sub(start).Seconds()
|
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}
|
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allRows = append(allRows, rows)
|
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}
|
|
|
|
if tx != nil {
|
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err = tx.Commit()
|
|
}
|
|
return allRows, err
|
|
}
|
|
|
|
// Backup writes a consistent snapshot of the database to the given file.
|
|
// This function can be called when changes to the database are in flight.
|
|
func (db *DB) Backup(path string) error {
|
|
dstDB, err := Open(path)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
if err := copyDatabase(dstDB, db); err != nil {
|
|
return fmt.Errorf("backup database: %s", err)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// Copy copies the contents of the database to the given database. All other
|
|
// attributes of the given database remain untouched e.g. whether it's an
|
|
// on-disk database. This function can be called when changes to the source
|
|
// database are in flight.
|
|
func (db *DB) Copy(dstDB *DB) error {
|
|
if err := copyDatabase(dstDB, db); err != nil {
|
|
return fmt.Errorf("copy database: %s", err)
|
|
}
|
|
return nil
|
|
}
|
|
|
|
// Serialize returns a byte slice representation of the SQLite database. For
|
|
// an ordinary on-disk database file, the serialization is just a copy of the
|
|
// disk file. For an in-memory database or a "TEMP" database, the serialization
|
|
// is the same sequence of bytes which would be written to disk if that database
|
|
// were backed up to disk.
|
|
func (db *DB) Serialize() ([]byte, error) {
|
|
conn, err := db.roDB.Conn(context.Background())
|
|
if err != nil {
|
|
return nil, err
|
|
}
|
|
defer conn.Close()
|
|
|
|
var b []byte
|
|
f := func(driverConn interface{}) error {
|
|
c := driverConn.(*sqlite3.SQLiteConn)
|
|
b = c.Serialize("")
|
|
if b == nil {
|
|
return fmt.Errorf("failed to serialize database")
|
|
}
|
|
return nil
|
|
}
|
|
|
|
if err := conn.Raw(f); err != nil {
|
|
return nil, err
|
|
}
|
|
return b, nil
|
|
}
|
|
|
|
// Dump writes a consistent snapshot of the database in SQL text format.
|
|
// This function can be called when changes to the database are in flight.
|
|
func (db *DB) Dump(w io.Writer) error {
|
|
conn, err := db.roDB.Conn(context.Background())
|
|
if err != nil {
|
|
return err
|
|
}
|
|
defer conn.Close()
|
|
|
|
// Convenience function to convert string query to protobuf.
|
|
commReq := func(query string) *command.Request {
|
|
return &command.Request{
|
|
Statements: []*command.Statement{
|
|
{
|
|
Sql: query,
|
|
},
|
|
},
|
|
}
|
|
}
|
|
|
|
if _, err := w.Write([]byte("PRAGMA foreign_keys=OFF;\nBEGIN TRANSACTION;\n")); err != nil {
|
|
return err
|
|
}
|
|
|
|
// Get the schema.
|
|
query := `SELECT "name", "type", "sql" FROM "sqlite_master"
|
|
WHERE "sql" NOT NULL AND "type" == 'table' ORDER BY "name"`
|
|
rows, err := db.queryWithConn(commReq(query), false, conn)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
row := rows[0]
|
|
for _, v := range row.Values {
|
|
table := v[0].(string)
|
|
var stmt string
|
|
|
|
if table == "sqlite_sequence" {
|
|
stmt = `DELETE FROM "sqlite_sequence";`
|
|
} else if table == "sqlite_stat1" {
|
|
stmt = `ANALYZE "sqlite_master";`
|
|
} else if strings.HasPrefix(table, "sqlite_") {
|
|
continue
|
|
} else {
|
|
stmt = v[2].(string)
|
|
}
|
|
|
|
if _, err := w.Write([]byte(fmt.Sprintf("%s;\n", stmt))); err != nil {
|
|
return err
|
|
}
|
|
|
|
tableIndent := strings.Replace(table, `"`, `""`, -1)
|
|
r, err := db.queryWithConn(commReq(fmt.Sprintf(`PRAGMA table_info("%s")`, tableIndent)),
|
|
false, conn)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
var columnNames []string
|
|
for _, w := range r[0].Values {
|
|
columnNames = append(columnNames, fmt.Sprintf(`'||quote("%s")||'`, w[1].(string)))
|
|
}
|
|
|
|
query = fmt.Sprintf(`SELECT 'INSERT INTO "%s" VALUES(%s)' FROM "%s";`,
|
|
tableIndent,
|
|
strings.Join(columnNames, ","),
|
|
tableIndent)
|
|
r, err = db.queryWithConn(commReq(query), false, conn)
|
|
|
|
if err != nil {
|
|
return err
|
|
}
|
|
for _, x := range r[0].Values {
|
|
y := fmt.Sprintf("%s;\n", x[0].(string))
|
|
if _, err := w.Write([]byte(y)); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
}
|
|
|
|
// Do indexes, triggers, and views.
|
|
query = `SELECT "name", "type", "sql" FROM "sqlite_master"
|
|
WHERE "sql" NOT NULL AND "type" IN ('index', 'trigger', 'view')`
|
|
rows, err = db.queryWithConn(commReq(query), false, conn)
|
|
if err != nil {
|
|
return err
|
|
}
|
|
row = rows[0]
|
|
for _, v := range row.Values {
|
|
if _, err := w.Write([]byte(fmt.Sprintf("%s;\n", v[2]))); err != nil {
|
|
return err
|
|
}
|
|
}
|
|
|
|
if _, err := w.Write([]byte("COMMIT;\n")); err != nil {
|
|
return err
|
|
}
|
|
|
|
return nil
|
|
}
|
|
|
|
func copyDatabase(dst *DB, src *DB) error {
|
|
dstConn, err := dst.rwDB.Conn(context.Background())
|
|
if err != nil {
|
|
return err
|
|
}
|
|
defer dstConn.Close()
|
|
srcConn, err := src.roDB.Conn(context.Background())
|
|
if err != nil {
|
|
return err
|
|
}
|
|
defer srcConn.Close()
|
|
|
|
var dstSQLiteConn *sqlite3.SQLiteConn
|
|
|
|
// Define the backup function.
|
|
bf := func(driverConn interface{}) error {
|
|
srcSQLiteConn := driverConn.(*sqlite3.SQLiteConn)
|
|
return copyDatabaseConnection(dstSQLiteConn, srcSQLiteConn)
|
|
}
|
|
|
|
return dstConn.Raw(
|
|
func(driverConn interface{}) error {
|
|
dstSQLiteConn = driverConn.(*sqlite3.SQLiteConn)
|
|
return srcConn.Raw(bf)
|
|
})
|
|
}
|
|
|
|
func copyDatabaseConnection(dst, src *sqlite3.SQLiteConn) error {
|
|
bk, err := dst.Backup("main", src, "main")
|
|
if err != nil {
|
|
return err
|
|
}
|
|
|
|
for {
|
|
done, err := bk.Step(-1)
|
|
if err != nil {
|
|
bk.Finish()
|
|
return err
|
|
}
|
|
if done {
|
|
break
|
|
}
|
|
time.Sleep(bkDelay * time.Millisecond)
|
|
}
|
|
return bk.Finish()
|
|
}
|
|
|
|
// parametersToValues maps values in the proto params to SQL driver values.
|
|
func parametersToValues(parameters []*command.Parameter) ([]interface{}, error) {
|
|
if parameters == nil {
|
|
return nil, nil
|
|
}
|
|
|
|
values := make([]interface{}, len(parameters))
|
|
for i := range parameters {
|
|
switch w := parameters[i].GetValue().(type) {
|
|
case *command.Parameter_I:
|
|
values[i] = w.I
|
|
case *command.Parameter_D:
|
|
values[i] = w.D
|
|
case *command.Parameter_B:
|
|
values[i] = w.B
|
|
case *command.Parameter_Y:
|
|
values[i] = w.Y
|
|
case *command.Parameter_S:
|
|
values[i] = w.S
|
|
default:
|
|
return nil, fmt.Errorf("unsupported type: %T", w)
|
|
}
|
|
}
|
|
return values, nil
|
|
}
|
|
|
|
// normalizeRowValues performs some normalization of values in the returned rows.
|
|
// Text values come over (from sqlite-go) as []byte instead of strings
|
|
// for some reason, so we have explicitly convert (but only when type
|
|
// is "text" so we don't affect BLOB types)
|
|
func normalizeRowValues(row []interface{}, types []string) []interface{} {
|
|
for i, v := range row {
|
|
if isTextType(types[i]) {
|
|
val, ok := v.([]byte)
|
|
if ok {
|
|
row[i] = string(val)
|
|
}
|
|
}
|
|
}
|
|
return row
|
|
}
|
|
|
|
// isTextType returns whether the given type has a SQLite text affinity.
|
|
// http://www.sqlite.org/datatype3.html
|
|
func isTextType(t string) bool {
|
|
return t == "text" ||
|
|
t == "json" ||
|
|
t == "" ||
|
|
strings.HasPrefix(t, "varchar") ||
|
|
strings.HasPrefix(t, "varying character") ||
|
|
strings.HasPrefix(t, "nchar") ||
|
|
strings.HasPrefix(t, "native character") ||
|
|
strings.HasPrefix(t, "nvarchar") ||
|
|
strings.HasPrefix(t, "clob")
|
|
}
|
|
|
|
func randomString() string {
|
|
var output strings.Builder
|
|
chars := "abcdedfghijklmnopqrstABCDEFGHIJKLMNOP"
|
|
for i := 0; i < 20; i++ {
|
|
random := rand.Intn(len(chars))
|
|
randomChar := chars[random]
|
|
output.WriteString(string(randomChar))
|
|
}
|
|
return output.String()
|
|
}
|