MM-50427: Make MM survive DB replica outage (#22888)

We monitor the health of DB replicas, and on a fatal error,
take them out of the pool.

On a separate goroutine, we keep pinging the unhealthy replicas,
and on getting a good response back, we add them back to the pool.

https://mattermost.atlassian.net/browse/MM-50427

```release-note
Mattermost is now resilient against DB replica outages and will
dynamically choose a replica if it's alive.

Also added a config parameter ReplicaMonitorIntervalSeconds
whose default value is 5. This controls how frequently unhealthy
replicas will be monitored for liveness check.
```

Co-authored-by: Mattermost Build <build@mattermost.com>
Этот коммит содержится в:
Agniva De Sarker
2023-04-19 17:03:18 +05:30
коммит произвёл GitHub
родитель 5d5c1d90bf
Коммит c34a50a6c7
13 изменённых файлов: 245 добавлений и 121 удалений

Просмотреть файл

@@ -6,9 +6,12 @@ package sqlstore
import (
"context"
"database/sql"
"errors"
"net"
"regexp"
"strconv"
"strings"
"sync/atomic"
"time"
"unicode"
@@ -66,14 +69,18 @@ type sqlxDBWrapper struct {
*sqlx.DB
queryTimeout time.Duration
trace bool
isOnline *atomic.Bool
}
func newSqlxDBWrapper(db *sqlx.DB, timeout time.Duration, trace bool) *sqlxDBWrapper {
return &sqlxDBWrapper{
w := &sqlxDBWrapper{
DB: db,
queryTimeout: timeout,
trace: trace,
isOnline: &atomic.Bool{},
}
w.isOnline.Store(true)
return w
}
func (w *sqlxDBWrapper) Stats() sql.DBStats {
@@ -83,19 +90,19 @@ func (w *sqlxDBWrapper) Stats() sql.DBStats {
func (w *sqlxDBWrapper) Beginx() (*sqlxTxWrapper, error) {
tx, err := w.DB.Beginx()
if err != nil {
return nil, err
return nil, w.checkErr(err)
}
return newSqlxTxWrapper(tx, w.queryTimeout, w.trace), nil
return newSqlxTxWrapper(tx, w.queryTimeout, w.trace, w), nil
}
func (w *sqlxDBWrapper) BeginXWithIsolation(opts *sql.TxOptions) (*sqlxTxWrapper, error) {
tx, err := w.DB.BeginTxx(context.Background(), opts)
if err != nil {
return nil, err
return nil, w.checkErr(err)
}
return newSqlxTxWrapper(tx, w.queryTimeout, w.trace), nil
return newSqlxTxWrapper(tx, w.queryTimeout, w.trace, w), nil
}
func (w *sqlxDBWrapper) Get(dest any, query string, args ...any) error {
@@ -109,7 +116,7 @@ func (w *sqlxDBWrapper) Get(dest any, query string, args ...any) error {
}(time.Now())
}
return w.DB.GetContext(ctx, dest, query, args...)
return w.checkErr(w.DB.GetContext(ctx, dest, query, args...))
}
func (w *sqlxDBWrapper) GetBuilder(dest any, builder Builder) error {
@@ -134,7 +141,7 @@ func (w *sqlxDBWrapper) NamedExec(query string, arg any) (sql.Result, error) {
}(time.Now())
}
return w.DB.NamedExecContext(ctx, query, arg)
return w.checkErrWithResult(w.DB.NamedExecContext(ctx, query, arg))
}
func (w *sqlxDBWrapper) Exec(query string, args ...any) (sql.Result, error) {
@@ -161,7 +168,7 @@ func (w *sqlxDBWrapper) ExecNoTimeout(query string, args ...any) (sql.Result, er
}(time.Now())
}
return w.DB.ExecContext(context.Background(), query, args...)
return w.checkErrWithResult(w.DB.ExecContext(context.Background(), query, args...))
}
// ExecRaw is like Exec but without any rebinding of params. You need to pass
@@ -176,7 +183,7 @@ func (w *sqlxDBWrapper) ExecRaw(query string, args ...any) (sql.Result, error) {
}(time.Now())
}
return w.DB.ExecContext(ctx, query, args...)
return w.checkErrWithResult(w.DB.ExecContext(ctx, query, args...))
}
func (w *sqlxDBWrapper) NamedQuery(query string, arg any) (*sqlx.Rows, error) {
@@ -192,7 +199,7 @@ func (w *sqlxDBWrapper) NamedQuery(query string, arg any) (*sqlx.Rows, error) {
}(time.Now())
}
return w.DB.NamedQueryContext(ctx, query, arg)
return w.checkErrWithRows(w.DB.NamedQueryContext(ctx, query, arg))
}
func (w *sqlxDBWrapper) QueryRowX(query string, args ...any) *sqlx.Row {
@@ -220,7 +227,7 @@ func (w *sqlxDBWrapper) QueryX(query string, args ...any) (*sqlx.Rows, error) {
}(time.Now())
}
return w.DB.QueryxContext(ctx, query, args)
return w.checkErrWithRows(w.DB.QueryxContext(ctx, query, args))
}
func (w *sqlxDBWrapper) Select(dest any, query string, args ...any) error {
@@ -238,7 +245,7 @@ func (w *sqlxDBWrapper) SelectCtx(ctx context.Context, dest any, query string, a
}(time.Now())
}
return w.DB.SelectContext(ctx, dest, query, args...)
return w.checkErr(w.DB.SelectContext(ctx, dest, query, args...))
}
func (w *sqlxDBWrapper) SelectBuilder(dest any, builder Builder) error {
@@ -254,13 +261,15 @@ type sqlxTxWrapper struct {
*sqlx.Tx
queryTimeout time.Duration
trace bool
dbw *sqlxDBWrapper
}
func newSqlxTxWrapper(tx *sqlx.Tx, timeout time.Duration, trace bool) *sqlxTxWrapper {
func newSqlxTxWrapper(tx *sqlx.Tx, timeout time.Duration, trace bool, dbw *sqlxDBWrapper) *sqlxTxWrapper {
return &sqlxTxWrapper{
Tx: tx,
queryTimeout: timeout,
trace: trace,
dbw: dbw,
}
}
@@ -275,7 +284,7 @@ func (w *sqlxTxWrapper) Get(dest any, query string, args ...any) error {
}(time.Now())
}
return w.Tx.GetContext(ctx, dest, query, args...)
return w.dbw.checkErr(w.Tx.GetContext(ctx, dest, query, args...))
}
func (w *sqlxTxWrapper) GetBuilder(dest any, builder Builder) error {
@@ -284,13 +293,13 @@ func (w *sqlxTxWrapper) GetBuilder(dest any, builder Builder) error {
return err
}
return w.Get(dest, query, args...)
return w.dbw.checkErr(w.Get(dest, query, args...))
}
func (w *sqlxTxWrapper) Exec(query string, args ...any) (sql.Result, error) {
query = w.Tx.Rebind(query)
return w.ExecRaw(query, args...)
return w.dbw.checkErrWithResult(w.ExecRaw(query, args...))
}
func (w *sqlxTxWrapper) ExecNoTimeout(query string, args ...any) (sql.Result, error) {
@@ -302,7 +311,7 @@ func (w *sqlxTxWrapper) ExecNoTimeout(query string, args ...any) (sql.Result, er
}(time.Now())
}
return w.Tx.ExecContext(context.Background(), query, args...)
return w.dbw.checkErrWithResult(w.Tx.ExecContext(context.Background(), query, args...))
}
func (w *sqlxTxWrapper) ExecBuilder(builder Builder) (sql.Result, error) {
@@ -326,7 +335,7 @@ func (w *sqlxTxWrapper) ExecRaw(query string, args ...any) (sql.Result, error) {
}(time.Now())
}
return w.Tx.ExecContext(ctx, query, args...)
return w.dbw.checkErrWithResult(w.Tx.ExecContext(ctx, query, args...))
}
func (w *sqlxTxWrapper) NamedExec(query string, arg any) (sql.Result, error) {
@@ -342,7 +351,7 @@ func (w *sqlxTxWrapper) NamedExec(query string, arg any) (sql.Result, error) {
}(time.Now())
}
return w.Tx.NamedExecContext(ctx, query, arg)
return w.dbw.checkErrWithResult(w.Tx.NamedExecContext(ctx, query, arg))
}
func (w *sqlxTxWrapper) NamedQuery(query string, arg any) (*sqlx.Rows, error) {
@@ -386,7 +395,7 @@ func (w *sqlxTxWrapper) NamedQuery(query string, arg any) (*sqlx.Rows, error) {
}
}
return res.rows, res.err
return res.rows, w.dbw.checkErr(res.err)
}
func (w *sqlxTxWrapper) QueryRowX(query string, args ...any) *sqlx.Row {
@@ -414,7 +423,7 @@ func (w *sqlxTxWrapper) QueryX(query string, args ...any) (*sqlx.Rows, error) {
}(time.Now())
}
return w.Tx.QueryxContext(ctx, query, args)
return w.dbw.checkErrWithRows(w.Tx.QueryxContext(ctx, query, args))
}
func (w *sqlxTxWrapper) Select(dest any, query string, args ...any) error {
@@ -428,7 +437,7 @@ func (w *sqlxTxWrapper) Select(dest any, query string, args ...any) error {
}(time.Now())
}
return w.Tx.SelectContext(ctx, dest, query, args...)
return w.dbw.checkErr(w.Tx.SelectContext(ctx, dest, query, args...))
}
func (w *sqlxTxWrapper) SelectBuilder(dest any, builder Builder) error {
@@ -459,3 +468,23 @@ func printArgs(query string, dur time.Duration, args ...any) {
}
mlog.Debug(query, fields...)
}
func (w *sqlxDBWrapper) checkErrWithResult(res sql.Result, err error) (sql.Result, error) {
return res, w.checkErr(err)
}
func (w *sqlxDBWrapper) checkErrWithRows(res *sqlx.Rows, err error) (*sqlx.Rows, error) {
return res, w.checkErr(err)
}
func (w *sqlxDBWrapper) checkErr(err error) error {
var netError *net.OpError
if errors.As(err, &netError) && (!netError.Temporary() && !netError.Timeout()) {
w.isOnline.Store(false)
}
return err
}
func (w *sqlxDBWrapper) Online() bool {
return w.isOnline.Load()
}