Austin
b2e8b64c0b
重构MySQL迁移逻辑，新增acquireMigrationLock适配Percona XtraDB Cluster的pxc_strict_mode限制，将原有的GET_LOCK迁移锁替换为更兼容的方案，同时为各迁移流程添加快速检查路径减少锁竞争
37 lines
1.2 KiB
Go
37 lines
1.2 KiB
Go
//go:build mysql
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// +build mysql
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package mysql
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import (
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"context"
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"database/sql"
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"errors"
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"github.com/jmoiron/sqlx"
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)
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// acquireMigrationLock wraps SELECT GET_LOCK so that schema migrations keep
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// working on Percona XtraDB Cluster where pxc_strict_mode=ENFORCING prohibits
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// named locks: instead of failing, locked=false is returned and the caller
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// proceeds without the lock. This is safe because Galera's total order
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// isolation serializes DDL across the cluster, and every migration using this
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// helper is idempotent: steps are guarded by existence checks, so concurrent
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// runs at worst fail with duplicate-key errors and are retried on the next
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// startup.
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func acquireMigrationLock(ctx context.Context, conn *sqlx.Conn, lockExpr string) (locked bool, unlock func(), err error) {
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var held sql.NullInt64
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if err = conn.QueryRowContext(ctx, "SELECT GET_LOCK("+lockExpr+", 60)").Scan(&held); err != nil {
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if isPXCStrictModeNamedLockError(err) {
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return false, nil, nil
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}
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return false, nil, err
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}
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if !held.Valid || held.Int64 != 1 {
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return false, nil, errors.New("mysql: timed out waiting for schema migration lock")
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}
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return true, func() {
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conn.ExecContext(ctx, "SELECT RELEASE_LOCK("+lockExpr+")")
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}, nil
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}
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