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Online DDL: remove legacy "stowaway table" logic #12288

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merged 2 commits into from
Feb 15, 2023
Merged

Online DDL: remove legacy "stowaway table" logic #12288

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07342e6
Online DDL: remove legacy stowaway table logic
shlomi-noach Feb 9, 2023
ed7b214
removed column from table definition
shlomi-noach Feb 12, 2023
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38 changes: 1 addition & 37 deletions go/vt/vttablet/onlineddl/executor.go
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Original file line number Diff line number Diff line change
Expand Up @@ -777,7 +777,7 @@ func (e *Executor) cutOverVReplMigration(ctx context.Context, s *VReplStream) er
}

if !isVreplicationTestSuite {
// A bit early on, we generate names for stowaway and temporary tables
// A bit early on, we generate a name for the sentry table
// We do this here because right now we're in a safe place where nothing happened yet. If there's an error now, bail out
// and no harm done.
// Later on, when traffic is blocked and tables renamed, that's a more dangerous place to be in; we want as little logic
Expand Down Expand Up @@ -3509,30 +3509,6 @@ func (e *Executor) reviewRunningMigrations(ctx context.Context) (countRunnning i
postponeCompletion := row.AsBool("postpone_completion", false)
elapsedSeconds := row.AsInt64("elapsed_seconds", 0)

if stowawayTable := row.AsString("stowaway_table", ""); stowawayTable != "" {
// whoa
// stowawayTable is an original table stowed away while cutting over a vrepl migration, see call to cutOverVReplMigration() down below in this function.
// In a normal operation, the table should not exist outside the scope of cutOverVReplMigration
// If it exists, that means a tablet crashed while running a cut-over, and left the database in a bad state, where the migrated table does not exist.
// thankfully, we have tracked this situation and just realized what happened. Now, first thing to do is to restore the original table.
log.Infof("found stowaway table %s journal in migration %s for table %s", stowawayTable, uuid, onlineDDL.Table)
attemptMade, err := e.renameTableIfApplicable(ctx, stowawayTable, onlineDDL.Table)
if err != nil {
// unable to restore table; we bail out, and we will try again next round.
return countRunnning, cancellable, err
}
// success
if attemptMade {
log.Infof("stowaway table %s restored back into %s", stowawayTable, onlineDDL.Table)
} else {
log.Infof("stowaway table %s did not exist and there was no need to restore it", stowawayTable)
}
// OK good, table restored. We can remove the record.
if err := e.updateMigrationStowawayTable(ctx, uuid, ""); err != nil {
return countRunnning, cancellable, err
}
}

uuidsFoundRunning[uuid] = true

_ = e.updateMigrationUserThrottleRatio(ctx, uuid, currentUserThrottleRatio)
Expand Down Expand Up @@ -4327,18 +4303,6 @@ func (e *Executor) updateMigrationReadyToComplete(ctx context.Context, uuid stri
return nil
}

func (e *Executor) updateMigrationStowawayTable(ctx context.Context, uuid string, tableName string) error {
query, err := sqlparser.ParseAndBind(sqlUpdateMigrationStowawayTable,
sqltypes.StringBindVariable(tableName),
sqltypes.StringBindVariable(uuid),
)
if err != nil {
return err
}
_, err = e.execQuery(ctx, query)
return err
}

func (e *Executor) updateMigrationUserThrottleRatio(ctx context.Context, uuid string, ratio float64) error {
query, err := sqlparser.ParseAndBind(sqlUpdateMigrationUserThrottleRatio,
sqltypes.Float64BindVariable(ratio),
Expand Down
7 changes: 0 additions & 7 deletions go/vt/vttablet/onlineddl/schema.go
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Original file line number Diff line number Diff line change
Expand Up @@ -100,11 +100,6 @@ const (
WHERE
migration_uuid=%a
`
sqlUpdateMigrationStowawayTable = `UPDATE _vt.schema_migrations
SET stowaway_table=%a
WHERE
migration_uuid=%a
`
sqlUpdateMigrationUserThrottleRatio = `UPDATE _vt.schema_migrations
SET user_throttle_ratio=%a
WHERE
Expand Down Expand Up @@ -278,7 +273,6 @@ const (
sqlSelectRunningMigrations = `SELECT
migration_uuid,
postpone_completion,
stowaway_table,
timestampdiff(second, started_timestamp, now()) as elapsed_seconds
FROM _vt.schema_migrations
WHERE
Expand Down Expand Up @@ -382,7 +376,6 @@ const (
is_view,
ready_to_complete,
reverted_uuid,
stowaway_table,
rows_copied,
vitess_liveness_indicator,
user_throttle_ratio,
Expand Down