mirror of
https://github.com/matrix-org/dendrite
synced 2024-11-14 13:51:20 +01:00
52 lines
1.3 KiB
Go
52 lines
1.3 KiB
Go
// Copyright 2018 New Vector Ltd
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// http://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
package storage
|
|
|
|
import (
|
|
"context"
|
|
"database/sql"
|
|
)
|
|
|
|
const txnIDSchema = `
|
|
-- Keeps a count of the current transaction ID
|
|
CREATE SEQUENCE IF NOT EXISTS txn_id_counter START 1;
|
|
`
|
|
|
|
const selectTxnIDSQL = "SELECT nextval('txn_id_counter')"
|
|
|
|
type txnStatements struct {
|
|
selectTxnIDStmt *sql.Stmt
|
|
}
|
|
|
|
func (s *txnStatements) prepare(db *sql.DB) (err error) {
|
|
_, err = db.Exec(txnIDSchema)
|
|
if err != nil {
|
|
return
|
|
}
|
|
|
|
if s.selectTxnIDStmt, err = db.Prepare(selectTxnIDSQL); err != nil {
|
|
return
|
|
}
|
|
|
|
return
|
|
}
|
|
|
|
// selectTxnID selects the latest ascending transaction ID
|
|
func (s *txnStatements) selectTxnID(
|
|
ctx context.Context,
|
|
) (txnID int, err error) {
|
|
err = s.selectTxnIDStmt.QueryRowContext(ctx).Scan(&txnID)
|
|
return
|
|
}
|