MDEV-11094: Blackhole table updates on slave fail when row annotation is enabled

Problem:
=======
rpl_blackhole.test fails when executed with following options
mysqld=--binlog_annotate_row_events=1, mysqld=--replicate_annotate_row_events=1

Test output:
------------
worker[1] Using MTR_BUILD_THREAD 300, with reserved ports 16000..16019
rpl.rpl_blackhole_bug 'mix'              [ pass ]    791
rpl.rpl_blackhole_bug 'row'              [ fail ]
Replicate_Wild_Ignore_Table
Last_Errno	1032
Last_Error	Could not execute Update_rows_v1 event on table test.t1; Can't find
record in 't1', Error_code: 1032; handler error HA_ERR_END_OF_FILE; the event's
master log master-bin.000001, end_log_pos 1510

Analysis:
=========
Enabling "replicate_annotate_row_events" on slave, Tells the slave to write
annotate rows events received from the master to its own binary log. The
received annotate events are applied after the Gtid event as shown below.
thd->query() will be set to the actual query received from the master, through
annotate event. Annotate_rows event should not be deleted after the event is
applied as the thd->query will be used to generate new Annotate_rows event
during applying the subsequent Rows events. After the last Rows event has been
applied, the saved Annotate_rows event (if any) will be deleted.

In balckhole engine all the DML operations are noops as they donot store any
data. They simply return success without doing any operation. But the existing
strictly expects thd->query() to be 'NULL' to identify that row based
replication is in use. This assumption will fail when row annotations are
enabled as the query is not 'NULL'. Hence various row based operations like
'update', 'delete', 'index lookup' will fail when row annotations are enabled.

Fix:
===
Extend the row based replication check to include row annotations as well.
i.e Either the thd->query() is NULL or thd->query() points to query and row
annotations are in use.

1 files changed, 22 insertions, 6 deletions

diff --git a/storage/blackhole/ha_blackhole.cc b/storage/blackhole/ha_blackhole.cc
index 01aaa9ea15f..43bcdc541a1 100644
--- a/storage/blackhole/ha_blackhole.cc
+++ b/storage/blackhole/ha_blackhole.cc
@@ -25,6 +25,16 @@
 #include "ha_blackhole.h"
 #include "sql_class.h"                          // THD, SYSTEM_THREAD_SLAVE_SQL
 
+static bool is_row_based_replication(THD *thd)
+{
+  /*
+    A row event which has its thd->query() == NULL or a row event which has
+    replicate_annotate_row_events enabled. In the later case the thd->query()
+    will be pointing to the query, received through replicated annotate event
+    from master.
+  */
+  return ((thd->query() == NULL) || thd->variables.binlog_annotate_row_events);
+}
 /* Static declarations for handlerton */
 
 static handler *blackhole_create_handler(handlerton *hton,
@@ -109,7 +119,8 @@ int ha_blackhole::update_row(const uchar *old_data, uchar *new_data)
 {
   DBUG_ENTER("ha_blackhole::update_row");
   THD *thd= ha_thd();
-  if (thd->system_thread == SYSTEM_THREAD_SLAVE_SQL && thd->query() == NULL)
+  if (thd->system_thread == SYSTEM_THREAD_SLAVE_SQL &&
+      is_row_based_replication(thd))
     DBUG_RETURN(0);
   DBUG_RETURN(HA_ERR_WRONG_COMMAND);
 }
@@ -118,7 +129,8 @@ int ha_blackhole::delete_row(const uchar *buf)
 {
   DBUG_ENTER("ha_blackhole::delete_row");
   THD *thd= ha_thd();
-  if (thd->system_thread == SYSTEM_THREAD_SLAVE_SQL && thd->query() == NULL)
+  if (thd->system_thread == SYSTEM_THREAD_SLAVE_SQL &&
+      is_row_based_replication(thd))
     DBUG_RETURN(0);
   DBUG_RETURN(HA_ERR_WRONG_COMMAND);
 }
@@ -135,7 +147,8 @@ int ha_blackhole::rnd_next(uchar *buf)
   int rc;
   DBUG_ENTER("ha_blackhole::rnd_next");
   THD *thd= ha_thd();
-  if (thd->system_thread == SYSTEM_THREAD_SLAVE_SQL && thd->query() == NULL)
+  if (thd->system_thread == SYSTEM_THREAD_SLAVE_SQL &&
+      is_row_based_replication(thd))
     rc= 0;
   else
     rc= HA_ERR_END_OF_FILE;
@@ -220,7 +233,8 @@ int ha_blackhole::index_read_map(uchar * buf, const uchar * key,
   int rc;
   DBUG_ENTER("ha_blackhole::index_read");
   THD *thd= ha_thd();
-  if (thd->system_thread == SYSTEM_THREAD_SLAVE_SQL && thd->query() == NULL)
+  if (thd->system_thread == SYSTEM_THREAD_SLAVE_SQL &&
+      is_row_based_replication(thd))
     rc= 0;
   else
     rc= HA_ERR_END_OF_FILE;
@@ -235,7 +249,8 @@ int ha_blackhole::index_read_idx_map(uchar * buf, uint idx, const uchar * key,
   int rc;
   DBUG_ENTER("ha_blackhole::index_read_idx");
   THD *thd= ha_thd();
-  if (thd->system_thread == SYSTEM_THREAD_SLAVE_SQL && thd->query() == NULL)
+  if (thd->system_thread == SYSTEM_THREAD_SLAVE_SQL &&
+      is_row_based_replication(thd))
     rc= 0;
   else
     rc= HA_ERR_END_OF_FILE;
@@ -249,7 +264,8 @@ int ha_blackhole::index_read_last_map(uchar * buf, const uchar * key,
   int rc;
   DBUG_ENTER("ha_blackhole::index_read_last");
   THD *thd= ha_thd();
-  if (thd->system_thread == SYSTEM_THREAD_SLAVE_SQL && thd->query() == NULL)
+  if (thd->system_thread == SYSTEM_THREAD_SLAVE_SQL &&
+      is_row_based_replication(thd))
     rc= 0;
   else
     rc= HA_ERR_END_OF_FILE;