add description and optimize tests

doc/command-line-flags.md

@@ -247,7 +247,16 @@ Allows `gh-ost` to connect to the MySQL servers using encrypted connections, but
 `--ssl-key=/path/to/ssl-key.key`: SSL private key file (in PEM format).
 
 ### storage-engine
-default is `innodb`. When set to `rocksdb`, some necessary changes (e.g. sets isolation level to READ_COMMITTED) is made to support rocksdb as transactional engine. 
+default is `innodb`, and `rocksdb`as an optional. InnoDB and RocksDB are both transactional engines, supporting both shared and exclusive row locks.
+
+But RocksDB currently lacks a few features support compared to InnoDB:
+- Gap Locks
+- Foreign Key
+- Generated Columns
+- Spatial
+- Geometry
+
+When `--storage-engine=rocksdb`, `gh-ost` will make some changes necessary (e.g. sets isolation level to `READ_COMMITTED`) to support RocksDB.
 
 ### test-on-replica
 

go/base/context.go

@@ -295,8 +295,6 @@ func (this *MigrationContext) SetConnectionConfig(storageEngine string) error {
 	switch storageEngine {
 	case "rocksdb":
 		transactionIsolation = "READ-COMMITTED"
-	case "innodb":
-		transactionIsolation = "REPEATABLE-READ"
 	default:
 		transactionIsolation = "REPEATABLE-READ"
 	}

go/cmd/gh-ost/main.go

@@ -252,6 +252,9 @@ func main() {
 	if *replicationLagQuery != "" {
 		migrationContext.Log.Warning("--replication-lag-query is deprecated")
 	}
+	if *storageEngine == "rocksdb" {
+		migrationContext.Log.Warning("RocksDB storage engine support is experimental")
+	}
 
 	switch *cutOver {
 	case "atomic", "default", "":

script/cibuild-gh-ost-replica-tests

@@ -71,33 +71,9 @@ test_mysql_version() {
   if echo "$mysql_server" | egrep -i "percona" ; then
     echo "### Preparing for rocksdb in PerconaServer"
     gh-ost-test-mysql-master -uroot -e 'INSTALL PLUGIN ROCKSDB SONAME "ha_rocksdb.so"'
-    gh-ost-test-mysql-master -uroot -e 'INSTALL PLUGIN ROCKSDB_CFSTATS SONAME "ha_rocksdb.so"'
-    gh-ost-test-mysql-master -uroot -e 'INSTALL PLUGIN ROCKSDB_DBSTATS SONAME "ha_rocksdb.so"'
-    gh-ost-test-mysql-master -uroot -e 'INSTALL PLUGIN ROCKSDB_PERF_CONTEXT SONAME "ha_rocksdb.so"'
-    gh-ost-test-mysql-master -uroot -e 'INSTALL PLUGIN ROCKSDB_PERF_CONTEXT_GLOBAL SONAME "ha_rocksdb.so"'
-    gh-ost-test-mysql-master -uroot -e 'INSTALL PLUGIN ROCKSDB_CF_OPTIONS SONAME "ha_rocksdb.so"'
-    gh-ost-test-mysql-master -uroot -e 'INSTALL PLUGIN ROCKSDB_GLOBAL_INFO SONAME "ha_rocksdb.so"'
-    gh-ost-test-mysql-master -uroot -e 'INSTALL PLUGIN ROCKSDB_COMPACTION_STATS SONAME "ha_rocksdb.so"'
-    gh-ost-test-mysql-master -uroot -e 'INSTALL PLUGIN ROCKSDB_DDL SONAME "ha_rocksdb.so"'
-    gh-ost-test-mysql-master -uroot -e 'INSTALL PLUGIN ROCKSDB_INDEX_FILE_MAP SONAME "ha_rocksdb.so"'
-    gh-ost-test-mysql-master -uroot -e 'INSTALL PLUGIN ROCKSDB_LOCKS SONAME "ha_rocksdb.so"'
-    gh-ost-test-mysql-master -uroot -e 'INSTALL PLUGIN ROCKSDB_TRX SONAME "ha_rocksdb.so"'
-    gh-ost-test-mysql-master -uroot -e 'INSTALL PLUGIN ROCKSDB_DEADLOCK SONAME "ha_rocksdb.so"'
     gh-ost-test-mysql-master -uroot -e 'set global default_storage_engine="ROCKSDB"'
     gh-ost-test-mysql-master -uroot -e 'set global transaction_isolation="READ-COMMITTED"'
     gh-ost-test-mysql-replica -uroot -e 'INSTALL PLUGIN ROCKSDB SONAME "ha_rocksdb.so"'
-    gh-ost-test-mysql-replica -uroot -e 'INSTALL PLUGIN ROCKSDB_CFSTATS SONAME "ha_rocksdb.so"'
-    gh-ost-test-mysql-replica -uroot -e 'INSTALL PLUGIN ROCKSDB_DBSTATS SONAME "ha_rocksdb.so"'
-    gh-ost-test-mysql-replica -uroot -e 'INSTALL PLUGIN ROCKSDB_PERF_CONTEXT SONAME "ha_rocksdb.so"'
-    gh-ost-test-mysql-replica -uroot -e 'INSTALL PLUGIN ROCKSDB_PERF_CONTEXT_GLOBAL SONAME "ha_rocksdb.so"'
-    gh-ost-test-mysql-replica -uroot -e 'INSTALL PLUGIN ROCKSDB_CF_OPTIONS SONAME "ha_rocksdb.so"'
-    gh-ost-test-mysql-replica -uroot -e 'INSTALL PLUGIN ROCKSDB_GLOBAL_INFO SONAME "ha_rocksdb.so"'
-    gh-ost-test-mysql-replica -uroot -e 'INSTALL PLUGIN ROCKSDB_COMPACTION_STATS SONAME "ha_rocksdb.so"'
-    gh-ost-test-mysql-replica -uroot -e 'INSTALL PLUGIN ROCKSDB_DDL SONAME "ha_rocksdb.so"'
-    gh-ost-test-mysql-replica -uroot -e 'INSTALL PLUGIN ROCKSDB_INDEX_FILE_MAP SONAME "ha_rocksdb.so"'
-    gh-ost-test-mysql-replica -uroot -e 'INSTALL PLUGIN ROCKSDB_LOCKS SONAME "ha_rocksdb.so"'
-    gh-ost-test-mysql-replica -uroot -e 'INSTALL PLUGIN ROCKSDB_TRX SONAME "ha_rocksdb.so"'
-    gh-ost-test-mysql-replica -uroot -e 'INSTALL PLUGIN ROCKSDB_DEADLOCK SONAME "ha_rocksdb.so"'
     gh-ost-test-mysql-replica -uroot -e 'set global default_storage_engine="ROCKSDB"'
     gh-ost-test-mysql-replica -uroot -e 'set global transaction_isolation="READ-COMMITTED"'