package pgx import ( "context" "errors" "fmt" "github.com/jackc/pgx/v5/pgconn" ) // QueuedQuery is a query that has been queued for execution via a Batch. type QueuedQuery struct { query string arguments []any fn batchItemFunc sd *pgconn.StatementDescription } type batchItemFunc func(br BatchResults) error // Query sets fn to be called when the response to qq is received. func (qq *QueuedQuery) Query(fn func(rows Rows) error) { qq.fn = func(br BatchResults) error { rows, _ := br.Query() defer rows.Close() err := fn(rows) if err != nil { return err } rows.Close() return rows.Err() } } // Query sets fn to be called when the response to qq is received. func (qq *QueuedQuery) QueryRow(fn func(row Row) error) { qq.fn = func(br BatchResults) error { row := br.QueryRow() return fn(row) } } // Exec sets fn to be called when the response to qq is received. func (qq *QueuedQuery) Exec(fn func(ct pgconn.CommandTag) error) { qq.fn = func(br BatchResults) error { ct, err := br.Exec() if err != nil { return err } return fn(ct) } } // Batch queries are a way of bundling multiple queries together to avoid // unnecessary network round trips. A Batch must only be sent once. type Batch struct { queuedQueries []*QueuedQuery } // Queue queues a query to batch b. query can be an SQL query or the name of a prepared statement. // The only pgx option argument that is supported is QueryRewriter. Queries are executed using the // connection's DefaultQueryExecMode. func (b *Batch) Queue(query string, arguments ...any) *QueuedQuery { qq := &QueuedQuery{ query: query, arguments: arguments, } b.queuedQueries = append(b.queuedQueries, qq) return qq } // Len returns number of queries that have been queued so far. func (b *Batch) Len() int { return len(b.queuedQueries) } type BatchResults interface { // Exec reads the results from the next query in the batch as if the query has been sent with Conn.Exec. Prefer // calling Exec on the QueuedQuery. Exec() (pgconn.CommandTag, error) // Query reads the results from the next query in the batch as if the query has been sent with Conn.Query. Prefer // calling Query on the QueuedQuery. Query() (Rows, error) // QueryRow reads the results from the next query in the batch as if the query has been sent with Conn.QueryRow. // Prefer calling QueryRow on the QueuedQuery. QueryRow() Row // Close closes the batch operation. All unread results are read and any callback functions registered with // QueuedQuery.Query, QueuedQuery.QueryRow, or QueuedQuery.Exec will be called. If a callback function returns an // error or the batch encounters an error subsequent callback functions will not be called. // // Close must be called before the underlying connection can be used again. Any error that occurred during a batch // operation may have made it impossible to resyncronize the connection with the server. In this case the underlying // connection will have been closed. // // Close is safe to call multiple times. If it returns an error subsequent calls will return the same error. Callback // functions will not be rerun. Close() error } type batchResults struct { ctx context.Context conn *Conn mrr *pgconn.MultiResultReader err error b *Batch qqIdx int closed bool endTraced bool } // Exec reads the results from the next query in the batch as if the query has been sent with Exec. func (br *batchResults) Exec() (pgconn.CommandTag, error) { if br.err != nil { return pgconn.CommandTag{}, br.err } if br.closed { return pgconn.CommandTag{}, fmt.Errorf("batch already closed") } query, arguments, _ := br.nextQueryAndArgs() if !br.mrr.NextResult() { err := br.mrr.Close() if err == nil { err = errors.New("no result") } if br.conn.batchTracer != nil { br.conn.batchTracer.TraceBatchQuery(br.ctx, br.conn, TraceBatchQueryData{ SQL: query, Args: arguments, Err: err, }) } return pgconn.CommandTag{}, err } commandTag, err := br.mrr.ResultReader().Close() if err != nil { br.err = err br.mrr.Close() } if br.conn.batchTracer != nil { br.conn.batchTracer.TraceBatchQuery(br.ctx, br.conn, TraceBatchQueryData{ SQL: query, Args: arguments, CommandTag: commandTag, Err: br.err, }) } return commandTag, br.err } // Query reads the results from the next query in the batch as if the query has been sent with Query. func (br *batchResults) Query() (Rows, error) { query, arguments, ok := br.nextQueryAndArgs() if !ok { query = "batch query" } if br.err != nil { return &baseRows{err: br.err, closed: true}, br.err } if br.closed { alreadyClosedErr := fmt.Errorf("batch already closed") return &baseRows{err: alreadyClosedErr, closed: true}, alreadyClosedErr } rows := br.conn.getRows(br.ctx, query, arguments) rows.batchTracer = br.conn.batchTracer if !br.mrr.NextResult() { rows.err = br.mrr.Close() if rows.err == nil { rows.err = errors.New("no result") } rows.closed = true if br.conn.batchTracer != nil { br.conn.batchTracer.TraceBatchQuery(br.ctx, br.conn, TraceBatchQueryData{ SQL: query, Args: arguments, Err: rows.err, }) } return rows, rows.err } rows.resultReader = br.mrr.ResultReader() return rows, nil } // QueryRow reads the results from the next query in the batch as if the query has been sent with QueryRow. func (br *batchResults) QueryRow() Row { rows, _ := br.Query() return (*connRow)(rows.(*baseRows)) } // Close closes the batch operation. Any error that occurred during a batch operation may have made it impossible to // resyncronize the connection with the server. In this case the underlying connection will have been closed. func (br *batchResults) Close() error { defer func() { if !br.endTraced { if br.conn != nil && br.conn.batchTracer != nil { br.conn.batchTracer.TraceBatchEnd(br.ctx, br.conn, TraceBatchEndData{Err: br.err}) } br.endTraced = true } }() if br.err != nil { return br.err } if br.closed { return nil } // Read and run fn for all remaining items for br.err == nil && !br.closed && br.b != nil && br.qqIdx < len(br.b.queuedQueries) { if br.b.queuedQueries[br.qqIdx].fn != nil { err := br.b.queuedQueries[br.qqIdx].fn(br) if err != nil { br.err = err } } else { br.Exec() } } br.closed = true err := br.mrr.Close() if br.err == nil { br.err = err } return br.err } func (br *batchResults) earlyError() error { return br.err } func (br *batchResults) nextQueryAndArgs() (query string, args []any, ok bool) { if br.b != nil && br.qqIdx < len(br.b.queuedQueries) { bi := br.b.queuedQueries[br.qqIdx] query = bi.query args = bi.arguments ok = true br.qqIdx++ } return } type pipelineBatchResults struct { ctx context.Context conn *Conn pipeline *pgconn.Pipeline lastRows *baseRows err error b *Batch qqIdx int closed bool endTraced bool } // Exec reads the results from the next query in the batch as if the query has been sent with Exec. func (br *pipelineBatchResults) Exec() (pgconn.CommandTag, error) { if br.err != nil { return pgconn.CommandTag{}, br.err } if br.closed { return pgconn.CommandTag{}, fmt.Errorf("batch already closed") } if br.lastRows != nil && br.lastRows.err != nil { return pgconn.CommandTag{}, br.err } query, arguments, _ := br.nextQueryAndArgs() results, err := br.pipeline.GetResults() if err != nil { br.err = err return pgconn.CommandTag{}, br.err } var commandTag pgconn.CommandTag switch results := results.(type) { case *pgconn.ResultReader: commandTag, br.err = results.Close() default: return pgconn.CommandTag{}, fmt.Errorf("unexpected pipeline result: %T", results) } if br.conn.batchTracer != nil { br.conn.batchTracer.TraceBatchQuery(br.ctx, br.conn, TraceBatchQueryData{ SQL: query, Args: arguments, CommandTag: commandTag, Err: br.err, }) } return commandTag, br.err } // Query reads the results from the next query in the batch as if the query has been sent with Query. func (br *pipelineBatchResults) Query() (Rows, error) { if br.err != nil { return &baseRows{err: br.err, closed: true}, br.err } if br.closed { alreadyClosedErr := fmt.Errorf("batch already closed") return &baseRows{err: alreadyClosedErr, closed: true}, alreadyClosedErr } if br.lastRows != nil && br.lastRows.err != nil { br.err = br.lastRows.err return &baseRows{err: br.err, closed: true}, br.err } query, arguments, ok := br.nextQueryAndArgs() if !ok { query = "batch query" } rows := br.conn.getRows(br.ctx, query, arguments) rows.batchTracer = br.conn.batchTracer br.lastRows = rows results, err := br.pipeline.GetResults() if err != nil { br.err = err rows.err = err rows.closed = true if br.conn.batchTracer != nil { br.conn.batchTracer.TraceBatchQuery(br.ctx, br.conn, TraceBatchQueryData{ SQL: query, Args: arguments, Err: err, }) } } else { switch results := results.(type) { case *pgconn.ResultReader: rows.resultReader = results default: err = fmt.Errorf("unexpected pipeline result: %T", results) br.err = err rows.err = err rows.closed = true } } return rows, rows.err } // QueryRow reads the results from the next query in the batch as if the query has been sent with QueryRow. func (br *pipelineBatchResults) QueryRow() Row { rows, _ := br.Query() return (*connRow)(rows.(*baseRows)) } // Close closes the batch operation. Any error that occurred during a batch operation may have made it impossible to // resyncronize the connection with the server. In this case the underlying connection will have been closed. func (br *pipelineBatchResults) Close() error { defer func() { if !br.endTraced { if br.conn.batchTracer != nil { br.conn.batchTracer.TraceBatchEnd(br.ctx, br.conn, TraceBatchEndData{Err: br.err}) } br.endTraced = true } }() if br.err == nil && br.lastRows != nil && br.lastRows.err != nil { br.err = br.lastRows.err return br.err } if br.closed { return br.err } // Read and run fn for all remaining items for br.err == nil && !br.closed && br.b != nil && br.qqIdx < len(br.b.queuedQueries) { if br.b.queuedQueries[br.qqIdx].fn != nil { err := br.b.queuedQueries[br.qqIdx].fn(br) if err != nil { br.err = err } } else { br.Exec() } } br.closed = true err := br.pipeline.Close() if br.err == nil { br.err = err } return br.err } func (br *pipelineBatchResults) earlyError() error { return br.err } func (br *pipelineBatchResults) nextQueryAndArgs() (query string, args []any, ok bool) { if br.b != nil && br.qqIdx < len(br.b.queuedQueries) { bi := br.b.queuedQueries[br.qqIdx] query = bi.query args = bi.arguments ok = true br.qqIdx++ } return }