feat: 🦭 MariaDB support 🦭

.github/workflows/replica-tests.yml

@@ -10,7 +10,7 @@ jobs:
     strategy:
       fail-fast: false
       matrix:
-        image: ['mysql:5.7.41','mysql:8.0.41','mysql:8.4.3','percona/percona-server:8.0.41-32']
+        image: ['mysql:5.7.41','mysql:8.0.41','mysql:8.4.3','percona/percona-server:8.0.41-32','mariadb:10.5.29','mariadb:10.6.27','mariadb:10.11.18','mariadb:11.4.12','mariadb:11.8.8']
     env:
       TEST_MYSQL_IMAGE: ${{ matrix.image }}
 

go/logic/applier.go

@@ -174,7 +174,7 @@ func (apl *Applier) AcquireMigrationLock(ctx context.Context) error {
 	// Use a dedicated *sql.DB so the pinned connection does not consume a
 	// slot in apl.db's small pool (mysql.MaxDBPoolConnections).
 	lockURI := apl.connectionConfig.GetDBUri(apl.migrationContext.DatabaseName)
-	lockDB, err := gosql.Open("mysql", lockURI)
+	lockDB, err := mysql.OpenDB(lockURI)
 	if err != nil {
 		return fmt.Errorf("failed to open migration lock DB: %w", err)
 	}

go/logic/inspect.go

@@ -244,7 +244,8 @@ func (isp *Inspector) validateGrants() error {
 			if strings.Contains(grant, `SUPER`) && strings.Contains(grant, ` ON *.*`) {
 				foundSuper = true
 			}
-			if strings.Contains(grant, `REPLICATION CLIENT`) && strings.Contains(grant, ` ON *.*`) {
+			// MariaDB renamed REPLICATION CLIENT to BINLOG MONITOR (10.5+); accept either.
+			if (strings.Contains(grant, `REPLICATION CLIENT`) || strings.Contains(grant, `BINLOG MONITOR`)) && strings.Contains(grant, ` ON *.*`) {
 				foundReplicationClient = true
 			}
 			if strings.Contains(grant, `REPLICATION SLAVE`) && strings.Contains(grant, ` ON *.*`) {

go/mysql/replica_terminology_map.go

@@ -1,6 +1,8 @@
 package mysql
 
 import (
+	"strings"
+
 	version "github.com/hashicorp/go-version"
 )
 
@@ -25,6 +27,13 @@ var MysqlReplicaTermMap = map[string]string{
 }
 
 func ReplicaTermFor(mysqlVersion string, term string) string {
+	// MariaDB reports versions >= 10, which compare greater than the 8.4
+	// cutoff, but it never adopted the new replica/source terminology. Keep
+	// the legacy terms for it.
+	if strings.Contains(strings.ToLower(mysqlVersion), "mariadb") {
+		return term
+	}
+
 	vs, err := version.NewVersion(mysqlVersion)
 	if err != nil {
 		// default to returning the same term if we cannot determine the version

go/mysql/replica_terminology_map_test.go

@@ -0,0 +1,24 @@
+/*
+   Copyright 2025 GitHub Inc.
+	 See https://github.com/github/gh-ost/blob/master/LICENSE
+*/
+
+package mysql
+
+import "testing"
+
+func TestReplicaTermForMariaDB11KeepsLegacyTerms(t *testing.T) {
+	tests := []string{
+		"master status",
+		"slave status",
+		"Slave_IO_Running",
+		"Seconds_Behind_Master",
+	}
+
+	version := "11.4.8-MariaDB-ubu2404-log"
+	for _, term := range tests {
+		if actual := ReplicaTermFor(version, term); actual != term {
+			t.Fatalf("term %q: expected MariaDB to keep legacy term %q, got %q", term, term, actual)
+		}
+	}
+}

go/mysql/utils.go

@@ -6,14 +6,17 @@
 package mysql
 
 import (
+	"context"
 	gosql "database/sql"
+	"database/sql/driver"
 	"fmt"
 	"strings"
 	"sync"
 	"time"
 
 	"github.com/github/gh-ost/go/sql"
 
+	gomysql "github.com/go-sql-driver/mysql"
 	"github.com/openark/golib/log"
 	"github.com/openark/golib/sqlutils"
 )
@@ -48,14 +51,68 @@ func (rlg *ReplicationLagResult) HasLag() bool {
 var knownDBs map[string]*gosql.DB = make(map[string]*gosql.DB)
 var knownDBsMutex = &sync.Mutex{}
 
+// initConnector wraps a driver.Connector to run a fixed set of statements on
+// every newly established connection (e.g. setting the transaction isolation
+// level), which the DSN-param mechanism can't express portably.
+type initConnector struct {
+	driver.Connector
+	statements []string
+}
+
+func (c *initConnector) Connect(ctx context.Context) (driver.Conn, error) {
+	conn, err := c.Connector.Connect(ctx)
+	if err != nil {
+		return nil, err
+	}
+	execer, ok := conn.(driver.ExecerContext)
+	if !ok {
+		conn.Close()
+		return nil, fmt.Errorf("mysql: driver connection does not implement driver.ExecerContext")
+	}
+	for _, stmt := range c.statements {
+		if _, err := execer.ExecContext(ctx, stmt, nil); err != nil {
+			conn.Close()
+			return nil, err
+		}
+	}
+	return conn, nil
+}
+
+// OpenDB opens a MySQL connection pool for the given DSN. A transaction_isolation
+// param is applied via the SQL-standard "SET SESSION TRANSACTION ISOLATION LEVEL"
+// statement on each new connection rather than being passed to the driver as a
+// system variable:
+// - "transaction_isolation" doesn't exist on MariaDB < 11.1, while
+// - "tx_isolation" doesn't exist on MySQL 8.0+ anymore, so no single variable name is portable.
+// The standard statement is accepted by every supported MySQL and MariaDB version.
+func OpenDB(mysql_uri string) (*gosql.DB, error) {
+	cfg, err := gomysql.ParseDSN(mysql_uri)
+	if err != nil {
+		return nil, err
+	}
+	var statements []string
+	if iso := strings.Trim(cfg.Params["transaction_isolation"], `"`); iso != "" {
+		delete(cfg.Params, "transaction_isolation")
+		statements = append(statements, "SET SESSION TRANSACTION ISOLATION LEVEL "+strings.ReplaceAll(iso, "-", " "))
+	}
+	connector, err := gomysql.NewConnector(cfg)
+	if err != nil {
+		return nil, err
+	}
+	if len(statements) > 0 {
+		connector = &initConnector{Connector: connector, statements: statements}
+	}
+	return gosql.OpenDB(connector), nil
+}
+
 func GetDB(migrationUuid string, mysql_uri string) (db *gosql.DB, exists bool, err error) {
 	cacheKey := migrationUuid + ":" + mysql_uri
 
 	knownDBsMutex.Lock()
 	defer knownDBsMutex.Unlock()
 
 	if db, exists = knownDBs[cacheKey]; !exists {
-		db, err = gosql.Open("mysql", mysql_uri)
+		db, err = OpenDB(mysql_uri)
 		if err != nil {
 			return nil, false, err
 		}
@@ -88,7 +145,7 @@ func GetReplicationLagFromSlaveStatus(dbVersion string, informationSchemaDb *gos
 func GetMasterKeyFromSlaveStatus(dbVersion string, connectionConfig *ConnectionConfig) (masterKey *InstanceKey, err error) {
 	currentUri := connectionConfig.GetDBUri("information_schema")
 	// This function is only called once, okay to not have a cached connection pool
-	db, err := gosql.Open("mysql", currentUri)
+	db, err := OpenDB(currentUri)
 	if err != nil {
 		return nil, err
 	}

localtests/fail-datetime-with-zero/sql_mode

@@ -0,0 +1 @@
+STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION

localtests/fail-existing-datetime-with-zero/sql_mode

@@ -0,0 +1 @@
+STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_ENGINE_SUBSTITUTION

localtests/generated-columns-add/extra_args

@@ -1 +1 @@
---alter="add column sum_ab int as (a + b) virtual not null"
+--alter="add column sum_ab int as (a + b) virtual"

localtests/generated-columns-rename/create.sql

@@ -3,7 +3,7 @@ create table gh_ost_test (
   id int auto_increment,
   a int not null,
   b int not null,
-  sum_ab int as (a + b) virtual not null,
+  sum_ab int as (a + b) virtual,
   primary key(id)
 ) auto_increment=1;
 

localtests/generated-columns-rename/extra_args

@@ -1 +1 @@
---alter="change sum_ab total_ab int as (a + b) virtual not null" --approve-renamed-columns
+--alter="change sum_ab total_ab int as (a + b) virtual" --approve-renamed-columns

localtests/generated-columns-unique/ignore_versions

@@ -1 +1 @@
-Percona
+Percona|mariadb

localtests/generated-columns/create.sql

@@ -3,7 +3,7 @@ create table gh_ost_test (
   id int auto_increment,
   a int not null,
   b int not null,
-  sum_ab int as (a + b) virtual not null,
+  sum_ab int as (a + b) virtual,
   primary key(id)
 ) auto_increment=1;
 

localtests/test.sh

@@ -95,7 +95,12 @@ verify_master_and_replica() {
     # Cache replica_terminology and seconds_behind_source values to avoid later checks.
     mysql_version="$(gh-ost-test-mysql-replica -s -s -e "select @@version")"
     mysql_version_comment="$(gh-ost-test-mysql-master -s -s -e "select @@version_comment")"
-    if [[ $mysql_version =~ "8.4" ]]; then
+    if [[ "$mysql_version" == *MariaDB* ]]; then
+        # MariaDB reports versions >= 10 but never adopted the replica/source
+        # terminology, so it keeps the legacy slave/Master wording.
+        replica_terminology="slave"
+        seconds_behind_source="Seconds_Behind_Master"
+    elif [[ $mysql_version =~ "8.4" ]]; then
         replica_terminology="replica"
         seconds_behind_source="Seconds_Behind_Source"
     else
@@ -129,13 +134,25 @@ echo_dot() {
 # there is no lag; waits up to 10s otherwise.
 # Relies on GTID (gtid_mode=ON); falls back to a short sleep if GTID is unavailable.
 wait_replica_caught_up() {
-    local master_gtid
-    master_gtid="$(gh-ost-test-mysql-master -s -s -e "select @@global.gtid_executed" 2>/dev/null)"
-    if [ -n "$master_gtid" ]; then
-        gh-ost-test-mysql-replica -s -s -e "do WAIT_FOR_EXECUTED_GTID_SET('${master_gtid}', 10)" >/dev/null 2>&1
+  if [[ "$mysql_version" == *MariaDB* ]]; then
+    # MariaDB has no gtid_executed / WAIT_FOR_EXECUTED_GTID_SET; use its own
+    # binlog GTID position and MASTER_GTID_WAIT.
+    local master_pos
+    master_pos="$(gh-ost-test-mysql-master -s -s -e "select @@global.gtid_binlog_pos")"
+    if [ -n "$master_pos" ]; then
+      gh-ost-test-mysql-replica -s -s -e "select master_gtid_wait('${master_pos}', 10)" >/dev/null 2>&1
     else
-        sleep 1
-    fi
+      sleep 1
+    fi
+    return
+  fi
+  local master_gtid
+  master_gtid="$(gh-ost-test-mysql-master -s -s -e "select @@global.gtid_executed" 2>/dev/null)"
+  if [ -n "$master_gtid" ]; then
+    gh-ost-test-mysql-replica -s -s -e "do WAIT_FOR_EXECUTED_GTID_SET('${master_gtid}', 10)" >/dev/null 2>&1
+  else
+    sleep 1
+  fi
 }
 
 start_replication() {
@@ -291,10 +308,16 @@ test_single() {
     if [ -f $tests_path/$test_name/gtid_mode ]; then
         target_gtid_mode=$(cat $tests_path/$test_name/gtid_mode)
         if [ "$current_gtid_mode" != "$target_gtid_mode" ]; then
-            echo "gtid_mode is ${current_gtid_mode}, expected ${target_gtid_mode}"
-            exit 1
-        fi
+            # MariaDB has no @@gtid_mode (reports "unsupported"); these tests
+      # target MySQL GTID behaviour, so skip rather than abort the run.
+      if [ "$current_gtid_mode" = "unsupported" ]; then
+        echo -n " skipping (gtid_mode unsupported)"
+        return 0
+      fi
+      echo "gtid_mode is ${current_gtid_mode}, expected ${target_gtid_mode}"
+      exit 1
     fi
+  fi
 
     if [ -f $tests_path/$test_name/sql_mode ]; then
         gh-ost-test-mysql-master --default-character-set=utf8mb4 test -e "set @@global.sql_mode='$(cat $tests_path/$test_name/sql_mode)'"

script/docker-compose.yml

@@ -12,7 +12,9 @@ services:
       - $CONF_PATH/create_user.sql:/docker-entrypoint-initdb.d/create_user.sql:ro
       - $CONF_PATH/common.cnf:$MYSQL_CONFD/common.cnf:ro
     healthcheck:
-      test: "mysql -h 127.0.0.1 -uroot -p$MYSQL_ROOT_PASSWORD -e 'select 1;' || exit 1"
+      # Client binary differs per flavor: MariaDB 11.x dropped the mysql-named
+      # symlinks, so its flavor.env sets MYSQL_CLIENT=mariadb.
+      test: "${MYSQL_CLIENT:-mysql} -h 127.0.0.1 -uroot -p$MYSQL_ROOT_PASSWORD -e 'select 1;' || exit 1"
       interval: 5s
       # Generous first-boot window: emulated amd64 5.7 on arm64 can take 60s+ to
       # init a fresh datadir. Health failures during start_period don't count, so

script/docker-gh-ost-replica-tests

@@ -110,16 +110,30 @@ compose_setup() {
     # Per-version config lives in docker/<flavor>-<major.minor> (e.g. mysql-8.0)
     # Derive <flavor> from the image repo basename and <major.minor> from the tag,
     # so registry/repo prefixes like percona/percona-server:8.0.41-32 resolve correctly.
-    local repo tag flavor major_minor
+    local repo tag flavor major_minor major
     repo="${TEST_MYSQL_IMAGE%%:*}"
     tag="${TEST_MYSQL_IMAGE##*:}"
     flavor="${repo##*/}"
     major_minor="$(echo "$tag" | cut -d. -f1-2)"
-    export CONF_PATH="$compose_path/docker/${flavor}-${major_minor}"
-    if [[ ! -d "$CONF_PATH" ]]; then
-        echo "No config dir for image '$TEST_MYSQL_IMAGE' (expected $CONF_PATH)" >&2
-        exit 1
+    major="$(echo "$tag" | cut -d. -f1)"
+
+    # Resolve by specificity: exact <flavor>-<major.minor>, then <flavor>-<major>,
+    # then bare <flavor>. Versions that share one config (e.g. all MariaDB) live
+    # in a single docker/<flavor> dir; a version (or major line) needing
+    # different config overrides it by adding its own more-specific dir.
+    local candidate
+    CONF_PATH=""
+    for candidate in "${flavor}-${major_minor}" "${flavor}-${major}" "${flavor}"; do
+      if [[ -d "$compose_path/docker/$candidate" ]]; then
+        CONF_PATH="$compose_path/docker/$candidate"
+        break
+      fi
+    done
+    if [[ -z "$CONF_PATH" ]]; then
+      echo "No config dir for image '$TEST_MYSQL_IMAGE' (looked for docker/${flavor}-${major_minor}, docker/${flavor}-${major}, docker/${flavor})" >&2
+      exit 1
     fi
+    export CONF_PATH
 
     # Per-flavor knobs, with defaults. Each flavor dir may override these in an
     # optional flavor.env (e.g. Percona reads config from /etc/my.cnf.d).

script/docker/mariadb/common.cnf

@@ -0,0 +1,10 @@
+[mysqld]
+character-set-server=utf8mb4
+# MariaDB ships the binary log off and binlog_format=MIXED by default; gh-ost
+# tails ROW events from the replica's own binlog under --test-on-replica, so
+# the replica needs log-bin + ROW + log-slave-updates. MariaDB tracks GTID
+# (gtid_binlog_pos) automatically once the binary log is on; it has no
+# gtid_mode/enforce_gtid_consistency knobs (those are MySQL-only).
+log-bin=mariadb-bin
+binlog-format=ROW
+log-slave-updates=ON

script/docker/mariadb/create_user.sql

@@ -0,0 +1,5 @@
+create user if not exists 'repl'@'%' identified by 'repl';
+grant replication slave on *.* to 'repl'@'%';
+create user if not exists 'gh-ost'@'%' identified by 'gh-ost';
+grant all on *.* to 'gh-ost'@'%';
+flush privileges;

script/docker/mariadb/flavor.env

@@ -0,0 +1,4 @@
+# MariaDB 11.x ships only the `mariadb`-named client; the `mysql` symlink is
+# gone. The compose healthcheck runs inside the container, so it needs the
+# real binary name.
+export MYSQL_CLIENT=mariadb

script/docker/mariadb/start_replication.sql

@@ -0,0 +1,2 @@
+change master to master_host='mysql-primary', master_port=3307, master_user='repl', master_password='repl', master_use_gtid=slave_pos;
+start slave;