Fix error message in MyRocks

Upstream commit ID : fb-mysql-5.6.35/3ed8b062eaacb2a8dd9616bbf4d3f267af7ba91e
PS-6864 : Merge fb-prod201902

Summary:
This is to fix the issue raised here - facebook/mysql-5.6#853
Essentially the correct parameter name is rocksdb_max_row_locks, so the error message should reflect this parameter name.

If RocksDB returns an error due to a "lock limit", then MyRocks will override the error message to indicate the correct parameter name.

Differential Revision: D13599991

fbshipit-source-id: 7c6bf6fa584

mysql-test/suite/rocksdb/r/rocksdb.result

@@ -1411,7 +1411,7 @@ Warning	1287	Setting user variables within expressions is deprecated and will be
 set @tmp1= @@rocksdb_max_row_locks;
 set rocksdb_max_row_locks= 20;
 update t1 set a=a+10;
-ERROR HY000: Got error 10 'Operation aborted: Failed to acquire lock due to max_num_locks limit' from ROCKSDB
+ERROR HY000: Got error 10 'Operation aborted: Failed to acquire lock due to rocksdb_max_row_locks limit' from ROCKSDB
 DROP TABLE t1;
 # 
 # Test AUTO_INCREMENT behavior problem,

storage/rocksdb/ha_rocksdb.cc

@@ -6509,13 +6509,20 @@ int ha_rocksdb::rdb_error_to_mysql(const rocksdb::Status &s,
     return -1;
   }
 
+  std::string errMsg;
+  if (s.IsLockLimit()) {
+    errMsg = "Operation aborted: Failed to acquire lock due to "
+             "rocksdb_max_row_locks limit";
+  } else {
+    errMsg = s.ToString();
+  }
+
   if (opt_msg) {
-    std::string concatenated_error =
-        s.ToString() + " (" + std::string(opt_msg) + ")";
+    std::string concatenated_error = errMsg + " (" + std::string(opt_msg) + ")";
     my_error(ER_GET_ERRMSG, MYF(0), s.code(), concatenated_error.c_str(),
              rocksdb_hton_name);
   } else {
-    my_error(ER_GET_ERRMSG, MYF(0), s.code(), s.ToString().c_str(),
+    my_error(ER_GET_ERRMSG, MYF(0), s.code(), errMsg.c_str(),
              rocksdb_hton_name);
   }