MDEV-13602: rocksdb.index_merge_rocksdb2 failed in buildbot

- Add include/index_merge*. Upstream has different files than MariaDB,
  use copies theirs, not ours.
- There was a prblem with running "DDL-like" commands with binlog=ON:
  MariaDB sets binlog_format=STATEMENT for the duration of such command
  to prevent RBR replication from catching (and replicating) updates to
  system tables.
  However, MyRocks tries to prevent any writes to MyRocks tables with
  binlog_format!=ROW.
- Added exceptions for DDL-type commands (ANALYZE TABLE, OPTIMIZE TABLE)
- Added special handling for "LOCK TABLE(s) myrocks_table WRITE".

Author: spetrunia

storage/rocksdb/ha_rocksdb.cc

@@ -9321,6 +9321,7 @@ const char *ha_rocksdb::thd_rocksdb_tmpdir() {
   return (tmp_dir);
 }
 
+
 /**
   @return
     HA_EXIT_SUCCESS  OK
@@ -9334,9 +9335,27 @@ int ha_rocksdb::external_lock(THD *const thd, int lock_type) {
   int res = HA_EXIT_SUCCESS;
   int binlog_format = my_core::thd_binlog_format(thd);
   bool unsafe_for_binlog = THDVAR(ha_thd(), unsafe_for_binlog);
+
+  /*
+    A note about (*) below: In fb/mysql, LOCK TABLE myrocks_table WRITE
+    - produces an error when @@binlog_format='ROW'.
+    - does not produce an error with @@binlog_format='STATEMENT'
+
+    We cannot easily provide this behavior in MariaDB, because LOCK ROWS
+    changes @@binlog_format for the duration of the statement.
+
+    Instead we will make the check in ha_rocksdb::start_stmt and will produce
+    an error in the first DML statement done under LOCK TABLE
+
+    (**) - The same happens for other "DDL-type" commands, so allow them here
+    as well.
+  */
   if (lock_type == F_WRLCK && !thd->rgi_slave && !unsafe_for_binlog &&
       binlog_format != BINLOG_FORMAT_ROW &&
       binlog_format != BINLOG_FORMAT_UNSPEC &&
+      thd->lex->sql_command != SQLCOM_LOCK_TABLES &&  // (*)
+      thd->lex->sql_command != SQLCOM_ANALYZE &&   // (**)
+      thd->lex->sql_command != SQLCOM_OPTIMIZE &&  // (**)
       my_core::thd_binlog_filter_ok(thd)) {
     my_error(ER_REQUIRE_ROW_BINLOG_FORMAT, MYF(0));
     DBUG_RETURN(HA_ERR_UNSUPPORTED);
@@ -9434,6 +9453,20 @@ int ha_rocksdb::external_lock(THD *const thd, int lock_type) {
 int ha_rocksdb::start_stmt(THD *const thd, thr_lock_type lock_type) {
   DBUG_ENTER_FUNC();
 
+  /*
+    MariaDB: the following is a copy of the check in ha_rocksdb::external_lock:
+  */
+  int binlog_format = my_core::thd_binlog_format(thd);
+  bool unsafe_for_binlog = THDVAR(ha_thd(), unsafe_for_binlog);
+  if (lock_type >= TL_WRITE_ALLOW_WRITE &&
+      !thd->rgi_slave && !unsafe_for_binlog &&
+      binlog_format != BINLOG_FORMAT_ROW &&
+      binlog_format != BINLOG_FORMAT_UNSPEC &&
+      my_core::thd_binlog_filter_ok(thd)) {
+    my_error(ER_REQUIRE_ROW_BINLOG_FORMAT, MYF(0));
+    DBUG_RETURN(HA_ERR_UNSUPPORTED);
+  }
+
   DBUG_ASSERT(thd != nullptr);
 
   Rdb_transaction *const tx = get_or_create_tx(thd);