a1a34b8150
- accepts --max-load - accepts multiple conditions in --max-load - throttle includes reason - chunk-size sanity check - change log state writes both in appending (history) mode and in replacing (current) mode - more atomic checks - inspecting ghost table columns, unique key - comparing unique keys between tables; sanity - intersecting columns between tables - prettify status - refactored throttle() and retries()
425 lines
14 KiB
Go
425 lines
14 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 logic
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import (
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gosql "database/sql"
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"fmt"
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"sync/atomic"
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"time"
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"github.com/github/gh-osc/go/base"
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"github.com/github/gh-osc/go/mysql"
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"github.com/github/gh-osc/go/sql"
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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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const (
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heartbeatIntervalSeconds = 1
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)
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// Applier reads data from the read-MySQL-server (typically a replica, but can be the master)
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// It is used for gaining initial status and structure, and later also follow up on progress and changelog
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type Applier struct {
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connectionConfig *mysql.ConnectionConfig
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db *gosql.DB
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migrationContext *base.MigrationContext
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}
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func NewApplier() *Applier {
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return &Applier{
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connectionConfig: base.GetMigrationContext().MasterConnectionConfig,
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migrationContext: base.GetMigrationContext(),
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}
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}
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func (this *Applier) InitDBConnections() (err error) {
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ApplierUri := this.connectionConfig.GetDBUri(this.migrationContext.DatabaseName)
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if this.db, _, err = sqlutils.GetDB(ApplierUri); err != nil {
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return err
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}
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if err := this.validateConnection(); err != nil {
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return err
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}
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return nil
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}
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// validateConnection issues a simple can-connect to MySQL
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func (this *Applier) validateConnection() error {
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query := `select @@global.port`
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var port int
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if err := this.db.QueryRow(query).Scan(&port); err != nil {
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return err
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}
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if port != this.connectionConfig.Key.Port {
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return fmt.Errorf("Unexpected database port reported: %+v", port)
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}
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log.Infof("connection validated on %+v", this.connectionConfig.Key)
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return nil
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}
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// CreateGhostTable creates the ghost table on the master
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func (this *Applier) CreateGhostTable() error {
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query := fmt.Sprintf(`create /* gh-osc */ table %s.%s like %s.%s`,
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sql.EscapeName(this.migrationContext.DatabaseName),
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sql.EscapeName(this.migrationContext.GetGhostTableName()),
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sql.EscapeName(this.migrationContext.DatabaseName),
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sql.EscapeName(this.migrationContext.OriginalTableName),
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)
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log.Infof("Creating ghost table %s.%s",
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sql.EscapeName(this.migrationContext.DatabaseName),
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sql.EscapeName(this.migrationContext.GetGhostTableName()),
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)
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if _, err := sqlutils.ExecNoPrepare(this.db, query); err != nil {
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return err
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}
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log.Infof("Ghost table created")
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return nil
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}
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// CreateGhostTable creates the ghost table on the master
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func (this *Applier) AlterGhost() error {
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query := fmt.Sprintf(`alter /* gh-osc */ table %s.%s %s`,
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sql.EscapeName(this.migrationContext.DatabaseName),
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sql.EscapeName(this.migrationContext.GetGhostTableName()),
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this.migrationContext.AlterStatement,
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)
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log.Infof("Altering ghost table %s.%s",
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sql.EscapeName(this.migrationContext.DatabaseName),
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sql.EscapeName(this.migrationContext.GetGhostTableName()),
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)
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log.Debugf("ALTER statement: %s", query)
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if _, err := sqlutils.ExecNoPrepare(this.db, query); err != nil {
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return err
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}
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log.Infof("Ghost table altered")
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return nil
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}
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// CreateChangelogTable creates the changelog table on the master
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func (this *Applier) CreateChangelogTable() error {
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query := fmt.Sprintf(`create /* gh-osc */ table %s.%s (
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id bigint auto_increment,
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last_update timestamp not null DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP,
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hint varchar(64) charset ascii not null,
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value varchar(255) charset ascii not null,
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primary key(id),
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unique key hint_uidx(hint)
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) auto_increment=2
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`,
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sql.EscapeName(this.migrationContext.DatabaseName),
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sql.EscapeName(this.migrationContext.GetChangelogTableName()),
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)
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log.Infof("Creating changelog table %s.%s",
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sql.EscapeName(this.migrationContext.DatabaseName),
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sql.EscapeName(this.migrationContext.GetChangelogTableName()),
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)
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if _, err := sqlutils.ExecNoPrepare(this.db, query); err != nil {
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return err
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}
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log.Infof("Changelog table created")
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return nil
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}
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// DropChangelogTable drops the changelog table on the master
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func (this *Applier) DropChangelogTable() error {
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query := fmt.Sprintf(`drop /* gh-osc */ table if exists %s.%s`,
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sql.EscapeName(this.migrationContext.DatabaseName),
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sql.EscapeName(this.migrationContext.GetChangelogTableName()),
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)
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log.Infof("Droppping changelog table %s.%s",
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sql.EscapeName(this.migrationContext.DatabaseName),
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sql.EscapeName(this.migrationContext.GetChangelogTableName()),
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)
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if _, err := sqlutils.ExecNoPrepare(this.db, query); err != nil {
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return err
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}
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log.Infof("Changelog table dropped")
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return nil
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}
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// WriteChangelog writes a value to the changelog table.
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// It returns the hint as given, for convenience
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func (this *Applier) WriteChangelog(hint, value string) (string, error) {
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query := fmt.Sprintf(`
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insert /* gh-osc */ into %s.%s
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(id, hint, value)
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values
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(NULL, ?, ?)
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on duplicate key update
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last_update=NOW(),
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value=VALUES(value)
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`,
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sql.EscapeName(this.migrationContext.DatabaseName),
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sql.EscapeName(this.migrationContext.GetChangelogTableName()),
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)
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_, err := sqlutils.Exec(this.db, query, hint, value)
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return hint, err
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}
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func (this *Applier) WriteChangelogState(value string) (string, error) {
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hint := "state"
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this.WriteChangelog(hint, value)
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return this.WriteChangelog(fmt.Sprintf("%s at %d", hint, time.Now().UnixNano()), value)
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}
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// InitiateHeartbeat creates a heartbeat cycle, writing to the changelog table.
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// This is done asynchronously
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func (this *Applier) InitiateHeartbeat() {
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go func() {
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numSuccessiveFailures := 0
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query := fmt.Sprintf(`
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insert /* gh-osc */ into %s.%s
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(id, hint, value)
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values
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(1, 'heartbeat', ?)
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on duplicate key update
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last_update=NOW(),
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value=VALUES(value)
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`,
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sql.EscapeName(this.migrationContext.DatabaseName),
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sql.EscapeName(this.migrationContext.GetChangelogTableName()),
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)
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injectHeartbeat := func() error {
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if _, err := sqlutils.ExecNoPrepare(this.db, query, time.Now().Format(time.RFC3339)); err != nil {
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numSuccessiveFailures++
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if numSuccessiveFailures > this.migrationContext.MaxRetries() {
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return log.Errore(err)
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}
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} else {
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numSuccessiveFailures = 0
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}
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return nil
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}
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injectHeartbeat()
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heartbeatTick := time.Tick(time.Duration(heartbeatIntervalSeconds) * time.Second)
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for range heartbeatTick {
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// Generally speaking, we would issue a goroutine, but I'd actually rather
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// have this blocked rather than spam the master in the event something
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// goes wrong
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if err := injectHeartbeat(); err != nil {
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return
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}
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}
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}()
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}
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// ReadMigrationMinValues
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func (this *Applier) ReadMigrationMinValues(uniqueKey *sql.UniqueKey) error {
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log.Debugf("Reading migration range according to key: %s", uniqueKey.Name)
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query, err := sql.BuildUniqueKeyMinValuesPreparedQuery(this.migrationContext.DatabaseName, this.migrationContext.OriginalTableName, uniqueKey.Columns)
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if err != nil {
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return err
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}
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rows, err := this.db.Query(query)
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if err != nil {
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return err
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}
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for rows.Next() {
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this.migrationContext.MigrationRangeMinValues = sql.NewColumnValues(len(uniqueKey.Columns))
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if err = rows.Scan(this.migrationContext.MigrationRangeMinValues.ValuesPointers...); err != nil {
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return err
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}
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}
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log.Infof("Migration min values: [%s]", this.migrationContext.MigrationRangeMinValues)
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return err
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}
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// ReadMigrationMinValues
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func (this *Applier) ReadMigrationMaxValues(uniqueKey *sql.UniqueKey) error {
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log.Debugf("Reading migration range according to key: %s", uniqueKey.Name)
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query, err := sql.BuildUniqueKeyMaxValuesPreparedQuery(this.migrationContext.DatabaseName, this.migrationContext.OriginalTableName, uniqueKey.Columns)
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if err != nil {
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return err
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}
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rows, err := this.db.Query(query)
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if err != nil {
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return err
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}
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for rows.Next() {
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this.migrationContext.MigrationRangeMaxValues = sql.NewColumnValues(len(uniqueKey.Columns))
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if err = rows.Scan(this.migrationContext.MigrationRangeMaxValues.ValuesPointers...); err != nil {
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return err
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}
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}
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log.Infof("Migration max values: [%s]", this.migrationContext.MigrationRangeMaxValues)
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return err
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}
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func (this *Applier) ReadMigrationRangeValues() error {
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if err := this.ReadMigrationMinValues(this.migrationContext.UniqueKey); err != nil {
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return err
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}
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if err := this.ReadMigrationMaxValues(this.migrationContext.UniqueKey); err != nil {
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return err
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}
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return nil
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}
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// __unused_IterationIsComplete lets us know when the copy-iteration phase is complete, i.e.
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// we've exhausted all rows
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func (this *Applier) __unused_IterationIsComplete() (bool, error) {
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if !this.migrationContext.HasMigrationRange() {
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return false, nil
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}
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if this.migrationContext.MigrationIterationRangeMinValues == nil {
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return false, nil
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}
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args := sqlutils.Args()
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compareWithIterationRangeStart, explodedArgs, err := sql.BuildRangePreparedComparison(this.migrationContext.UniqueKey.Columns, this.migrationContext.MigrationIterationRangeMinValues.AbstractValues(), sql.GreaterThanOrEqualsComparisonSign)
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if err != nil {
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return false, err
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}
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args = append(args, explodedArgs...)
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compareWithRangeEnd, explodedArgs, err := sql.BuildRangePreparedComparison(this.migrationContext.UniqueKey.Columns, this.migrationContext.MigrationRangeMaxValues.AbstractValues(), sql.LessThanComparisonSign)
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if err != nil {
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return false, err
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}
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args = append(args, explodedArgs...)
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query := fmt.Sprintf(`
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select /* gh-osc IterationIsComplete */ 1
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from %s.%s
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where (%s) and (%s)
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limit 1
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`,
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sql.EscapeName(this.migrationContext.DatabaseName),
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sql.EscapeName(this.migrationContext.OriginalTableName),
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compareWithIterationRangeStart,
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compareWithRangeEnd,
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)
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moreRowsFound := false
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err = sqlutils.QueryRowsMap(this.db, query, func(rowMap sqlutils.RowMap) error {
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moreRowsFound = true
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return nil
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}, args...)
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if err != nil {
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return false, err
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}
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return !moreRowsFound, nil
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}
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// CalculateNextIterationRangeEndValues reads the next-iteration-range-end unique key values,
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// which will be used for copying the next chunk of rows. Ir returns "false" if there is
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// no further chunk to work through, i.e. we're past the last chunk and are done with
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// itrating the range (and this done with copying row chunks)
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func (this *Applier) CalculateNextIterationRangeEndValues() (hasFurtherRange bool, err error) {
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this.migrationContext.MigrationIterationRangeMinValues = this.migrationContext.MigrationIterationRangeMaxValues
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if this.migrationContext.MigrationIterationRangeMinValues == nil {
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this.migrationContext.MigrationIterationRangeMinValues = this.migrationContext.MigrationRangeMinValues
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}
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query, explodedArgs, err := sql.BuildUniqueKeyRangeEndPreparedQuery(
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this.migrationContext.DatabaseName,
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this.migrationContext.OriginalTableName,
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this.migrationContext.UniqueKey.Columns,
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this.migrationContext.MigrationIterationRangeMinValues.AbstractValues(),
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this.migrationContext.MigrationRangeMaxValues.AbstractValues(),
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this.migrationContext.ChunkSize,
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fmt.Sprintf("iteration:%d", this.migrationContext.GetIteration()),
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)
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if err != nil {
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return hasFurtherRange, err
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}
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rows, err := this.db.Query(query, explodedArgs...)
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if err != nil {
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return hasFurtherRange, err
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}
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iterationRangeMaxValues := sql.NewColumnValues(len(this.migrationContext.UniqueKey.Columns))
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for rows.Next() {
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if err = rows.Scan(iterationRangeMaxValues.ValuesPointers...); err != nil {
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return hasFurtherRange, err
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}
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hasFurtherRange = true
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}
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if !hasFurtherRange {
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log.Debugf("Iteration complete: cannot find iteration end")
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return hasFurtherRange, nil
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}
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this.migrationContext.MigrationIterationRangeMaxValues = iterationRangeMaxValues
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// log.Debugf(
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// "column values: [%s]..[%s]; iteration: %d; chunk-size: %d",
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// this.migrationContext.MigrationIterationRangeMinValues,
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// this.migrationContext.MigrationIterationRangeMaxValues,
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// this.migrationContext.GetIteration(),
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// this.migrationContext.ChunkSize,
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// )
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return hasFurtherRange, nil
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}
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func (this *Applier) ApplyIterationInsertQuery() (chunkSize int64, rowsAffected int64, duration time.Duration, err error) {
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startTime := time.Now()
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chunkSize = atomic.LoadInt64(&this.migrationContext.ChunkSize)
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query, explodedArgs, err := sql.BuildRangeInsertPreparedQuery(
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this.migrationContext.DatabaseName,
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this.migrationContext.OriginalTableName,
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this.migrationContext.GetGhostTableName(),
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this.migrationContext.SharedColumns,
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this.migrationContext.UniqueKey.Name,
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this.migrationContext.UniqueKey.Columns,
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this.migrationContext.MigrationIterationRangeMinValues.AbstractValues(),
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this.migrationContext.MigrationIterationRangeMaxValues.AbstractValues(),
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this.migrationContext.GetIteration() == 0,
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this.migrationContext.IsTransactionalTable(),
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)
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if err != nil {
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return chunkSize, rowsAffected, duration, err
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}
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sqlResult, err := sqlutils.Exec(this.db, query, explodedArgs...)
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if err != nil {
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return chunkSize, rowsAffected, duration, err
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}
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rowsAffected, _ = sqlResult.RowsAffected()
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duration = time.Now().Sub(startTime)
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log.Debugf(
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"Issued INSERT on range: [%s]..[%s]; iteration: %d; chunk-size: %d",
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this.migrationContext.MigrationIterationRangeMinValues,
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this.migrationContext.MigrationIterationRangeMaxValues,
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this.migrationContext.GetIteration(),
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chunkSize)
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return chunkSize, rowsAffected, duration, nil
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}
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// LockTables
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func (this *Applier) LockTables() error {
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query := fmt.Sprintf(`lock /* gh-osc */ tables %s.%s write, %s.%s write, %s.%s write`,
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sql.EscapeName(this.migrationContext.DatabaseName),
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sql.EscapeName(this.migrationContext.OriginalTableName),
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sql.EscapeName(this.migrationContext.DatabaseName),
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sql.EscapeName(this.migrationContext.GetGhostTableName()),
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sql.EscapeName(this.migrationContext.DatabaseName),
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sql.EscapeName(this.migrationContext.GetChangelogTableName()),
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)
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log.Infof("Locking tables")
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if _, err := sqlutils.ExecNoPrepare(this.db, query); err != nil {
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return err
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}
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log.Infof("Tables locked")
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return nil
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}
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// UnlockTables
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func (this *Applier) UnlockTables() error {
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query := `unlock /* gh-osc */ tables`
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log.Infof("Unlocking tables")
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if _, err := sqlutils.ExecNoPrepare(this.db, query); err != nil {
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return err
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}
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log.Infof("Tables unlocked")
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return nil
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}
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func (this *Applier) ShowStatusVariable(variableName string) (result int64, err error) {
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query := fmt.Sprintf(`show global status like '%s'`, variableName)
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if err := this.db.QueryRow(query).Scan(&variableName, &result); err != nil {
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return 0, err
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}
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return result, nil
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}
|