bk commit into 5.1 tree (petr:1.2245) BUG#20139

[Petr Chardin]

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5.1 repository of cps. When cps does a push these changes will
be propagated to the main repository and, within 24 hours after the
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ChangeSet@stripped, 2006-08-03 17:23:37+04:00, petr@stripped +3 -0
  Fix Bug #20139 Infinite loop after "FLUSH" and "LOCK tabX, general_log"
  Due to incorrect handling of FLUSH TABLES, log tables were marked for flush,
  but not reopened. Later we started to wait for the log table to be closed
  (disabled) after the flush. And as nobody disabled logs in concurrent treads,
  the command lasted forever.
  After internal consultations it was decided to skip logs during FLUSH TABLES.
  The reasoning is that logging is done in the "log device", whatever it is
  which is always active and controlled by FLUSH LOGS. So, to flush logs
  one should use FLUSH LOGS, and not FLUSH TABLES.

  mysql-test/r/log_tables.result@stripped, 2006-08-03 17:23:22+04:00, petr@stripped +5 -0
    update result file

  mysql-test/t/log_tables.test@stripped, 2006-08-03 17:23:22+04:00, petr@stripped +10 -0
    add a test for the bug

  sql/sql_base.cc@stripped, 2006-08-03 17:23:22+04:00, petr@stripped +11 -7
    Skip log tables during FLUSH TABLES

# This is a BitKeeper patch.  What follows are the unified diffs for the
# set of deltas contained in the patch.  The rest of the patch, the part
# that BitKeeper cares about, is below these diffs.
# User:	petr
# Host:	owlet.
# Root:	/home/cps/mysql/trees/5.1-team

--- 1.336/sql/sql_base.cc	2006-08-03 17:23:50 +04:00
+++ 1.337/sql/sql_base.cc	2006-08-03 17:23:50 +04:00
@@ -1997,17 +1997,17 @@
        table= (TABLE*) hash_next(&open_cache, (byte*) key, key_length,
                                  &state))
   {
-    if (table->s->version != refresh_version)
+    /*
+      Here we flush tables marked for flush. However we never flush log
+      tables here. They are flushed only on FLUSH LOGS.
+    */
+    if (table->s->version != refresh_version && !table->s->log_table)
     {
       DBUG_PRINT("note",
                  ("Found table '%s.%s' with different refresh version",
                   table_list->db, table_list->table_name));
 
-      /*
-        Don't close tables if we are working with a log table or were
-        asked not to close the table explicitly
-      */
-      if (flags & MYSQL_LOCK_IGNORE_FLUSH || table->s->log_table)
+      if (flags & MYSQL_LOCK_IGNORE_FLUSH)
       {
         /* Force close at once after usage */
         thd->version= table->s->version;
@@ -2346,7 +2346,11 @@
 
   for (; table ; table=table->next)
   {
-    if (table->s->version != refresh_version)
+    /*
+      Reopen marked for flush. But close log tables. They are flushed only
+      explicitly on FLUSH LOGS
+    */
+    if (table->s->version != refresh_version && !table->s->log_table)
     {
       found=1;
       if (table->db_stat)

--- 1.5/mysql-test/r/log_tables.result	2006-08-03 17:23:50 +04:00
+++ 1.6/mysql-test/r/log_tables.result	2006-08-03 17:23:50 +04:00
@@ -72,3 +72,8 @@
 select * from mysql.slow_log;
 start_time	user_host	query_time	lock_time	rows_sent	rows_examined	db	last_insert_id	insert_id	server_id	sql_text
 TIMESTAMP	USER_HOST	QUERY_TIME	00:00:00	1	0	test	0	0	1	select sleep(2)
+flush tables with read lock;
+unlock tables;
+use mysql;
+lock tables general_log read local, help_category read local;
+unlock tables;

--- 1.10/mysql-test/t/log_tables.test	2006-08-03 17:23:50 +04:00
+++ 1.11/mysql-test/t/log_tables.test	2006-08-03 17:23:50 +04:00
@@ -171,6 +171,16 @@
 --replace_column 1 TIMESTAMP 2 USER_HOST 3 QUERY_TIME
 select * from mysql.slow_log;
 
+#
+# Bug #20139 Infinite loop after "FLUSH" and "LOCK tabX, general_log"
+#
+
+flush tables with read lock;
+unlock tables;
+use mysql;
+lock tables general_log read local, help_category read local;
+unlock tables;
+
 # kill all connections
 disconnect con1;
 disconnect con2;