07063a4181
- when `--test-on-replica`, the tested replica is implicitly a control replica - added `replication-lag-query`, an alternate query to `SHOW SLAVE STATUS` to get replication lag - throttling takes both the above into consideration
110 lines
3.5 KiB
Go
110 lines
3.5 KiB
Go
/*
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Copyright 2016 GitHub Inc.
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See https://github.com/github/gh-osc/blob/master/LICENSE
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*/
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package mysql
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import (
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gosql "database/sql"
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"fmt"
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"time"
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"github.com/outbrain/golib/log"
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"github.com/outbrain/golib/sqlutils"
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)
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// GetReplicationLag returns replication lag for a given connection config; either by explicit query
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// or via SHOW SLAVE STATUS
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func GetReplicationLag(connectionConfig *ConnectionConfig, replicationLagQuery string) (replicationLag time.Duration, err error) {
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dbUri := connectionConfig.GetDBUri("information_schema")
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var db *gosql.DB
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if db, _, err = sqlutils.GetDB(dbUri); err != nil {
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return replicationLag, err
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}
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if replicationLagQuery != "" {
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var floatLag float64
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err = db.QueryRow(replicationLagQuery).Scan(&floatLag)
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return time.Duration(int64(floatLag*1000)) * time.Millisecond, err
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}
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// No explicit replication lag query.
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err = sqlutils.QueryRowsMap(db, `show slave status`, func(m sqlutils.RowMap) error {
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secondsBehindMaster := m.GetNullInt64("Seconds_Behind_Master")
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if !secondsBehindMaster.Valid {
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return fmt.Errorf("Replication not running on %+v", connectionConfig.Key)
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}
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replicationLag = time.Duration(secondsBehindMaster.Int64) * time.Second
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return nil
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})
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return replicationLag, err
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}
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// GetMaxReplicationLag concurrently checks for replication lag on given list of instance keys,
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// each via GetReplicationLag
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func GetMaxReplicationLag(baseConnectionConfig *ConnectionConfig, instanceKeyMap *InstanceKeyMap, replicationLagQuery string) (replicationLag time.Duration, err error) {
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if instanceKeyMap.Len() == 0 {
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return 0, nil
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}
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lagsChan := make(chan time.Duration, instanceKeyMap.Len())
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errorsChan := make(chan error, instanceKeyMap.Len())
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for key := range *instanceKeyMap {
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connectionConfig := baseConnectionConfig.Duplicate()
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connectionConfig.Key = key
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go func() {
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lag, err := GetReplicationLag(connectionConfig, replicationLagQuery)
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lagsChan <- lag
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errorsChan <- err
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}()
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}
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for range *instanceKeyMap {
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if lagError := <-errorsChan; lagError != nil {
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err = lagError
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}
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if lag := <-lagsChan; lag.Nanoseconds() > replicationLag.Nanoseconds() {
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replicationLag = lag
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}
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}
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return replicationLag, err
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}
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func GetMasterKeyFromSlaveStatus(connectionConfig *ConnectionConfig) (masterKey *InstanceKey, err error) {
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currentUri := connectionConfig.GetDBUri("information_schema")
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db, _, err := sqlutils.GetDB(currentUri)
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if err != nil {
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return nil, err
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}
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err = sqlutils.QueryRowsMap(db, `show slave status`, func(rowMap sqlutils.RowMap) error {
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masterKey = &InstanceKey{
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Hostname: rowMap.GetString("Master_Host"),
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Port: rowMap.GetInt("Master_Port"),
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}
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return nil
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})
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return masterKey, err
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}
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func GetMasterConnectionConfigSafe(connectionConfig *ConnectionConfig, visitedKeys *InstanceKeyMap) (masterConfig *ConnectionConfig, err error) {
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log.Debugf("Looking for master on %+v", connectionConfig.Key)
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masterKey, err := GetMasterKeyFromSlaveStatus(connectionConfig)
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if err != nil {
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return nil, err
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}
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if masterKey == nil {
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return connectionConfig, nil
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}
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if !masterKey.IsValid() {
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return connectionConfig, nil
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}
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masterConfig = connectionConfig.Duplicate()
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masterConfig.Key = *masterKey
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log.Debugf("Master of %+v is %+v", connectionConfig.Key, masterConfig.Key)
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if visitedKeys.HasKey(masterConfig.Key) {
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return nil, fmt.Errorf("There seems to be a master-master setup at %+v. This is unsupported. Bailing out", masterConfig.Key)
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}
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visitedKeys.AddKey(masterConfig.Key)
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return GetMasterConnectionConfigSafe(masterConfig, visitedKeys)
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}
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