MDEV-19514 preparation: Remove innodb_change_buffering_debug=2

The setting innodb_change_buffering_debug=2 was supposed to inject a crash during change buffer merge. There is no public test for that functionality, and even if there were, it would be better to use DEBUG_SYNC to halt the thread that does change buffer merge, force a redo log flush from another thread, and finally kill the server externally.
MariaDB · Sep 9, 2019 · 43a6e81 · 43a6e81
1 parent 2336e0b
commit 43a6e81
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Showing 5 changed files with 12 additions and 24 deletions.
diff --git a/mysql-test/suite/sys_vars/r/innodb_change_buffering_debug_basic.result b/mysql-test/suite/sys_vars/r/innodb_change_buffering_debug_basic.result
@@ -55,6 +55,12 @@ Warnings:
 Warning	1292	Truncated incorrect innodb_change_buffering_debug value: '-2'
 set global innodb_change_buffering_debug=1e1;
 ERROR 42000: Incorrect argument type to variable 'innodb_change_buffering_debug'
+set global innodb_change_buffering_debug=2;
+Warnings:
+Warning	1292	Truncated incorrect innodb_change_buffering_debug value: '2'
+select @@global.innodb_change_buffering_debug;
+@@global.innodb_change_buffering_debug
+1
 SET @@global.innodb_change_buffering_debug = @start_global_value;
 SELECT @@global.innodb_change_buffering_debug;
 @@global.innodb_change_buffering_debug

diff --git a/mysql-test/suite/sys_vars/r/sysvars_innodb.result b/mysql-test/suite/sys_vars/r/sysvars_innodb.result
@@ -347,9 +347,9 @@ SESSION_VALUE	NULL
 DEFAULT_VALUE	0
 VARIABLE_SCOPE	GLOBAL
 VARIABLE_TYPE	INT UNSIGNED
-VARIABLE_COMMENT	Debug flags for InnoDB change buffering (0=none, 2=crash at merge)
+VARIABLE_COMMENT	Debug flags for InnoDB change buffering (0=none, 1=try to buffer)
 NUMERIC_MIN_VALUE	0
-NUMERIC_MAX_VALUE	2
+NUMERIC_MAX_VALUE	1
 NUMERIC_BLOCK_SIZE	0
 ENUM_VALUE_LIST	NULL
 READ_ONLY	NO

diff --git a/mysql-test/suite/sys_vars/t/innodb_change_buffering_debug_basic.test b/mysql-test/suite/sys_vars/t/innodb_change_buffering_debug_basic.test
@@ -48,9 +48,8 @@ set global innodb_change_buffering_debug='foo';
 set global innodb_change_buffering_debug=-2;
 --error ER_WRONG_TYPE_FOR_VAR
 set global innodb_change_buffering_debug=1e1;
-# The value 2 is supposed to kill the server if there are unmerged changes.
-# Do not try to set the value to 2 or anything that can be clamped to 2.
-#set global innodb_change_buffering_debug=2;
+set global innodb_change_buffering_debug=2;
+select @@global.innodb_change_buffering_debug;
 
 #
 # Cleanup

diff --git a/storage/innobase/handler/ha_innodb.cc b/storage/innobase/handler/ha_innodb.cc
@@ -20616,8 +20616,8 @@ static MYSQL_SYSVAR_ENUM(stats_method, srv_innodb_stats_method,
 #if defined UNIV_DEBUG || defined UNIV_IBUF_DEBUG
 static MYSQL_SYSVAR_UINT(change_buffering_debug, ibuf_debug,
   PLUGIN_VAR_RQCMDARG,
-  "Debug flags for InnoDB change buffering (0=none, 2=crash at merge)",
-  NULL, NULL, 0, 0, 2, 0);
+  "Debug flags for InnoDB change buffering (0=none, 1=try to buffer)",
+  NULL, NULL, 0, 0, 1, 0);
 
 static MYSQL_SYSVAR_BOOL(disable_background_merge,
   srv_ibuf_disable_background_merge,

diff --git a/storage/innobase/ibuf/ibuf0ibuf.cc b/storage/innobase/ibuf/ibuf0ibuf.cc
@@ -4241,23 +4241,6 @@ ibuf_delete_rec(
 	ut_ad(ibuf_rec_get_page_no(mtr, btr_pcur_get_rec(pcur)) == page_no);
 	ut_ad(ibuf_rec_get_space(mtr, btr_pcur_get_rec(pcur)) == space);
 
-#if defined UNIV_DEBUG || defined UNIV_IBUF_DEBUG
-	if (ibuf_debug == 2) {
-		/* Inject a fault (crash). We do this before trying
-		optimistic delete, because a pessimistic delete in the
-		change buffer would require a larger test case. */
-
-		/* Flag the buffered record as processed, to avoid
-		an assertion failure after crash recovery. */
-		btr_cur_set_deleted_flag_for_ibuf(
-			btr_pcur_get_rec(pcur), NULL, TRUE, mtr);
-
-		ibuf_mtr_commit(mtr);
-		log_write_up_to(LSN_MAX, true);
-		DBUG_SUICIDE();
-	}
-#endif /* UNIV_DEBUG || UNIV_IBUF_DEBUG */
-
 	success = btr_cur_optimistic_delete(btr_pcur_get_btr_cur(pcur),
 					    0, mtr);