MDEV-31777 ER_GET_ERRNO upon online alter on CONNECT table

Forbid Online for CONNECT.

sql/handler.h

@@ -371,7 +371,10 @@ enum chf_create_flags {
 /* Implements SELECT ... FOR UPDATE SKIP LOCKED */
 #define HA_CAN_SKIP_LOCKED  (1ULL << 61)
 
-#define HA_LAST_TABLE_FLAG HA_CAN_SKIP_LOCKED
+/* This engine is not compatible with Online ALTER TABLE */
+#define HA_NO_ONLINE_ALTER  (1ULL << 62)
+
+#define HA_LAST_TABLE_FLAG HA_NO_ONLINE_ALTER
 
 
 /* bits in index_flags(index_number) for what you can do with index */

sql/sql_table.cc

@@ -9908,7 +9908,8 @@ bool online_alter_check_autoinc(const THD *thd, const Alter_info *alter_info,
 static
 const char *online_alter_check_supported(const THD *thd,
                                          const Alter_info *alter_info,
-                                         const TABLE *table, bool *online)
+                                         const TABLE *table,
+                                         const TABLE *new_table, bool *online)
 {
   DBUG_ASSERT(*online);
 
@@ -9916,6 +9917,10 @@ const char *online_alter_check_supported(const THD *thd,
   if (!*online)
     return NULL;
 
+  *online= (new_table->file->ha_table_flags() & HA_NO_ONLINE_ALTER) == 0;
+  if (!*online)
+    return new_table->file->engine_name()->str;
+
   *online= table->s->sequence == NULL;
   if (!*online)
     return "SEQUENCE";
@@ -11023,20 +11028,6 @@ do_continue:;
   if (fk_prepare_copy_alter_table(thd, table, alter_info, &alter_ctx))
     goto err_new_table_cleanup;
 
-  if (online)
-  {
-    const char *reason= online_alter_check_supported(thd, alter_info, table,
-                                                     &online);
-    if (reason &&
-        alter_info->requested_lock == Alter_info::ALTER_TABLE_LOCK_NONE)
-    {
-      DBUG_ASSERT(!online);
-      my_error(ER_ALTER_OPERATION_NOT_SUPPORTED_REASON, MYF(0),
-               "LOCK=NONE", reason, "LOCK=SHARED");
-      goto err_new_table_cleanup;
-    }
-  }
-
   if (!table->s->tmp_table)
   {
     // If EXCLUSIVE lock is requested, upgrade already.
@@ -11108,6 +11099,21 @@ do_continue:;
     thd->session_tracker.state_change.mark_as_changed(thd);
   }
 
+  if (online)
+  {
+    const char *reason= online_alter_check_supported(thd, alter_info, table,
+                                                     new_table,
+                                                     &online);
+    if (reason &&
+        alter_info->requested_lock == Alter_info::ALTER_TABLE_LOCK_NONE)
+    {
+      DBUG_ASSERT(!online);
+      my_error(ER_ALTER_OPERATION_NOT_SUPPORTED_REASON, MYF(0),
+               "LOCK=NONE", reason, "LOCK=SHARED");
+      goto err_new_table_cleanup;
+    }
+  }
+
   /*
     Note: In case of MERGE table, we do not attach children. We do not
     copy data for MERGE tables. Only the children have data.

storage/connect/ha_connect.cc

@@ -1174,7 +1174,7 @@ ulonglong ha_connect::table_flags() const
 //                   HA_FAST_KEY_READ |  causes error when sorting (???)
                      HA_NO_TRANSACTIONS | HA_DUPLICATE_KEY_NOT_IN_ORDER |
                      HA_NO_BLOBS | HA_MUST_USE_TABLE_CONDITION_PUSHDOWN |
-                     HA_REUSES_FILE_NAMES;
+                     HA_REUSES_FILE_NAMES | HA_NO_ONLINE_ALTER;
   ha_connect *hp= (ha_connect*)this;
   PTOS        pos= hp->GetTableOptionStruct();
 

storage/connect/mysql-test/connect/r/alter.result

@@ -272,3 +272,11 @@ line
           2Two
           3Three
 DROP TABLE t1, t2;
+# MDEV-31777 ER_GET_ERRNO upon online alter with concurrent DML on
+# CONNECT table
+CREATE TABLE t (a INT) ENGINE=CONNECT TABLE_TYPE=DOS;
+Warnings:
+Warning	1105	No file name. Table will use t.dos
+ALTER TABLE t FORCE, ALGORITHM=COPY, LOCK=NONE;
+ERROR 0A000: LOCK=NONE is not supported. Reason: CONNECT. Try LOCK=SHARED
+DROP TABLE t;

storage/connect/mysql-test/connect/t/alter.test

@@ -133,6 +133,14 @@ SELECT * from t2;
 
 DROP TABLE t1, t2;
 
+
+--echo # MDEV-31777 ER_GET_ERRNO upon online alter with concurrent DML on
+--echo # CONNECT table
+CREATE TABLE t (a INT) ENGINE=CONNECT TABLE_TYPE=DOS;
+--error ER_ALTER_OPERATION_NOT_SUPPORTED_REASON
+ALTER TABLE t FORCE, ALGORITHM=COPY, LOCK=NONE;
+DROP TABLE t;
+
 #
 # Clean up
 #