From b489c89f739850ab448182390982b88b536667f2 Mon Sep 17 00:00:00 2001
From: Luis Soares <luis.soares@oracle.com>
Date: Thu, 24 Mar 2011 10:52:40 +0000
Subject: BUG#11766865: 60091: RBR + NO PK + UPDATE NULL VALUE --> SLAVE BREAK
 WITH ERROR HA_ERR_END_OF_

The slave was not able to find the correct row in the innodb
table, because the row fetched from the innodb table would not
match the before image. This happened because the (don't care)
bytes in the NULLed fields would change once the row was stored
in the storage engine (from zero to the default value). This
would make bulk memory comparison (using memcmp) to fail.

We fix this by taking a preventing measure and avoiding memcmp
for tables that contain nullable fields. Therefore, we protect
the slave search routine from engines that return arbitrary
values for don't care bytes (in the nulled fields). Instead, the
slave thread will only check null_bits and those fields that are
not set to NULL when comparing the before image against the
storage engine row.

mysql-test/extra/rpl_tests/rpl_record_compare.test:
  Added test case to the include file so that this is tested
  with more than one engine.
mysql-test/suite/rpl/r/rpl_row_rec_comp_innodb.result:
  Result update.
mysql-test/suite/rpl/r/rpl_row_rec_comp_myisam.result:
  Result update.
mysql-test/suite/rpl/t/rpl_row_rec_comp_myisam.test:
  Moved the include file last, so that the result from
  BUG#11766865 is not intermixed with the result for
  BUG#11760454.
sql/log_event.cc:
  Skips memory comparison if the table has nullable
  columns and compares only non-nulled fields in the
  field comparison loop.
---
 sql/log_event.cc | 31 ++++++++++++++++++++++++++-----
 1 file changed, 26 insertions(+), 5 deletions(-)

(limited to 'sql')

diff --git a/sql/log_event.cc b/sql/log_event.cc
index 0b938df1987..19f82b69048 100644
--- a/sql/log_event.cc
+++ b/sql/log_event.cc
@@ -8888,7 +8888,19 @@ static bool record_compare(TABLE *table)
     }
   }
 
-  if (table->s->blob_fields + table->s->varchar_fields == 0)
+  /**
+    Compare full record only if:
+    - there are no blob fields (otherwise we would also need 
+      to compare blobs contents as well);
+    - there are no varchar fields (otherwise we would also need
+      to compare varchar contents as well);
+    - there are no null fields, otherwise NULLed fields 
+      contents (i.e., the don't care bytes) may show arbitrary 
+      values, depending on how each engine handles internally.
+    */
+  if ((table->s->blob_fields + 
+       table->s->varchar_fields + 
+       table->s->null_fields) == 0)
   {
     result= cmp_record(table,record[1]);
     goto record_compare_exit;
@@ -8903,13 +8915,22 @@ static bool record_compare(TABLE *table)
     goto record_compare_exit;
   }
 
-  /* Compare updated fields */
+  /* Compare fields */
   for (Field **ptr=table->field ; *ptr ; ptr++)
   {
-    if ((*ptr)->cmp_binary_offset(table->s->rec_buff_length))
+
+    /**
+      We only compare field contents that are not null.
+      NULL fields (i.e., their null bits) were compared 
+      earlier.
+    */
+    if (!(*(ptr))->is_null())
     {
-      result= TRUE;
-      goto record_compare_exit;
+      if ((*ptr)->cmp_binary_offset(table->s->rec_buff_length))
+      {
+        result= TRUE;
+        goto record_compare_exit;
+      }
     }
   }
 
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