Merge lp:~stewart/percona-server/max-binlog-files into lp:percona-server/5.5

[Stewart Smith]

introduces new server parameter to limit the number of binlog files. Used with setting max file size for binlog you can rather effectively set maximum disk space used by binlogs.

Original Jenkins run:
http://jenkins.percona.com/view/PS%205.5/job/percona-server-5.5-param/385/

This run:
http://jenkins.percona.com/job/percona-server-5.5-param/451/

In this resubmitted req it's just addressing review comments.

[Stewart Smith (stewart)]

This is for (internal) issue 23617

--
Stewart Smith

[Laurynas Biveinis (laurynas-biveinis)]

The testcase has commit but does not have matching begin transaction or disable autocommit.
Perhaps rename err label to exit, as it is used for non-error returns too.

review: Needs Fixing

[Stewart Smith (stewart)]

On Fri, 01 Jun 2012 03:46:26 -0000, Laurynas Biveinis <email address hidden> wrote:
> The testcase has commit but does not have matching begin transaction
> or disable autocommit.

It does have a BEGIN;. It doesn't explicitly set engine to InnoDB,
although in this case it doesn't really matter what engine it executes
with, so I'm just running with default engine.

> Perhaps rename err label to exit, as it is used for non-error returns too.

I generally avoid exit as a label name due to exit(3) existing.
Using err as label is consistent with the rest of log.cc though.

--
Stewart Smith

[Laurynas Biveinis (laurynas-biveinis)]

OK, thanks for explaining.

review: Approve

[Alexey Kopytov (akopytov)]

Stewart,

- There is a problem in MYSQL_BIN_LOG::purge_logs_maximum_number() when
  some files cannot be purged when in use, e.g. when there's a slave
  reading that log file. It looks like in this case we will be spinning
  in a tight loop *and* holding the LOCK_index mutex *and* incrementing
  current_number_of_logs, so it will also be an infinite loop.

- I wonder if we really need that "do while()" loop?

- Please fix formatting in purge_logs_maximum_number(). I know it's
  mostly copy-pasted code, but fixing it is just "C-M-h C-M-\"

- Please don't follow a bad example established previously with adding
  variables to all_vars.result. Let's have max_binlog_files_basic.test
  instead. The test case says there should no variable names in
  all_vars.result, and the upstream server has none.

review: Needs Fixing

[Alexey Kopytov (akopytov)]

Forgot to mention that the comment header in the .test file should be fixed too (copy-paste from another test).

[Stewart Smith (stewart)]

http://jenkins.percona.com/job/percona-server-5.5-param/452/

(just set a sensible limit on max number of binlog files)

[Laurynas Biveinis (laurynas-biveinis)]

    --force-restart in percona_binlog_max_nr-master.opt is an MTR
    option, not mysqld one, so it should be removed.

    Please add a newline to that file.

    What does "FN_DYNVARS_072_01" mean in max_binlog_files_basic.test?

    while(find_next_log(&log_info, 0) == false) missing space after
    while and am not sure "== false" is the way to write it: there is
    an "if (find_next_log(&log_info, 0))" below.

    Use MYSQL_BIN_LOG::lock_index and unlock_index instead of directly
    touching the LOCK_index.

    Rev 253 and diff lines 579--580, is that a separate bug fixed?
    Maybe it needs an LP bug for it?

review: Needs Fixing

[Stewart Smith (stewart)]

> --force-restart in percona_binlog_max_nr-master.opt is an MTR
> option, not mysqld one, so it should be removed.

fixed

> Please add a newline to that file.

fixed

> What does "FN_DYNVARS_072_01" mean in max_binlog_files_basic.test?

This is just copied from max_binlog_size test

> while(find_next_log(&log_info, 0) == false) missing space after
> while and am not sure "== false" is the way to write it: there is
> an "if (find_next_log(&log_info, 0))" below.

fixed

> Use MYSQL_BIN_LOG::lock_index and unlock_index instead of directly
> touching the LOCK_index.

none of the existing code uses this

> Rev 253 and diff lines 579--580, is that a separate bug fixed?
> Maybe it needs an LP bug for it?

possibly should...

[Laurynas Biveinis (laurynas-biveinis)]

> > Rev 253 and diff lines 579--580, is that a separate bug fixed?
> > Maybe it needs an LP bug for it?

> possibly should...

So this is presumably bug 1036040? Then I have to ask all the boring questions about it: 1) does it apply to 5.1; 2) is there a testcase? (it's OK if it's percona_binlog_max_nr).

review: Needs Information

[Stewart Smith (stewart)]

> > > Rev 253 and diff lines 579--580, is that a separate bug fixed?
> > > Maybe it needs an LP bug for it?
>
> > possibly should...
>
> So this is presumably bug 1036040? Then I have to ask all the boring questions
> about it: 1) does it apply to 5.1; 2) is there a testcase? (it's OK if it's
> percona_binlog_max_nr).

1) no.

2) IIRC this was by code inspection and comparison to equiv mariadb code. Actual test case was pretty tricky IIRC.

[Laurynas Biveinis (laurynas-biveinis)]

review: Approve

=== modified file 'Percona-Server/mysql-test/r/mysqld--help-notwin.result'
--- Percona-Server/mysql-test/r/mysqld--help-notwin.result	2012-08-07 06:10:00 +0000
+++ Percona-Server/mysql-test/r/mysqld--help-notwin.result	2012-08-13 05:37:06 +0000
@@ -321,6 +321,11 @@
  --max-binlog-dump-events=# 
  Option used by mysql-test for debugging and testing of
  replication.
+ --max-binlog-files=# 
+ Maximum number of binlog files. Used with
+ --max-binlog-size this can be used to limit the total
+ amount of disk space used for the binlog. Default is 0,
+ don't limit.
  --max-binlog-size=# Binary log will be rotated automatically when the size
  exceeds this value. Will also apply to relay logs if
  max_relay_log_size is 0
@@ -913,6 +918,7 @@
 max-allowed-packet 1048576
 max-binlog-cache-size 18446744073709547520
 max-binlog-dump-events 0
+max-binlog-files 0
 max-binlog-size 1073741824
 max-binlog-stmt-cache-size 18446744073709547520
 max-connect-errors 10

=== modified file 'Percona-Server/mysql-test/r/mysqld--help-win.result'
--- Percona-Server/mysql-test/r/mysqld--help-win.result	2012-08-07 06:10:00 +0000
+++ Percona-Server/mysql-test/r/mysqld--help-win.result	2012-08-13 05:37:06 +0000
@@ -294,6 +294,11 @@
  --max-binlog-dump-events=# 
  Option used by mysql-test for debugging and testing of
  replication.
+ --max-binlog-files=# 
+ Maximum number of binlog files. Used with
+ --max-binlog-size this can be used to limit the total
+ amount of disk space used for the binlog. Default is 0,
+ don't limit.
  --max-binlog-size=# Binary log will be rotated automatically when the size
  exceeds this value. Will also apply to relay logs if
  max_relay_log_size is 0
@@ -857,6 +862,7 @@
 max-allowed-packet 1048576
 max-binlog-cache-size 18446744073709547520
 max-binlog-dump-events 0
+max-binlog-files 0
 max-binlog-size 1073741824
 max-binlog-stmt-cache-size 18446744073709547520
 max-connect-errors 10

=== modified file 'Percona-Server/mysql-test/r/percona_server_variables_debug.result'
--- Percona-Server/mysql-test/r/percona_server_variables_debug.result	2012-08-09 06:49:56 +0000
+++ Percona-Server/mysql-test/r/percona_server_variables_debug.result	2012-08-13 05:37:06 +0000
@@ -214,6 +214,7 @@
 LOW_PRIORITY_UPDATES
 MAX_ALLOWED_PACKET
 MAX_BINLOG_CACHE_SIZE
+MAX_BINLOG_FILES
 MAX_BINLOG_SIZE
 MAX_BINLOG_STMT_CACHE_SIZE
 MAX_CONNECTIONS

=== modified file 'Percona-Server/mysql-test/r/percona_server_variables_release.result'
--- Percona-Server/mysql-test/r/percona_server_variables_release.result	2012-08-07 06:10:00 +0000
+++ Percona-Server/mysql-test/r/percona_server_variables_release.result	2012-08-13 05:37:06 +0000
@@ -209,6 +209,7 @@
 LOW_PRIORITY_UPDATES
 MAX_ALLOWED_PACKET
 MAX_BINLOG_CACHE_SIZE
+MAX_BINLOG_FILES
 MAX_BINLOG_SIZE
 MAX_BINLOG_STMT_CACHE_SIZE
 MAX_CONNECTIONS

=== added file 'Percona-Server/mysql-test/suite/binlog/r/percona_binlog_max_nr.result'
--- Percona-Server/mysql-test/suite/binlog/r/percona_binlog_max_nr.result	1970-01-01 00:00:00 +0000
+++ Percona-Server/mysql-test/suite/binlog/r/percona_binlog_max_nr.result	2012-08-13 05:37:06 +0000
@@ -0,0 +1,30 @@
+RESET MASTER;
+##############################################################
+testing purge binary logs to max number on explicit FLUSH LOGS
+##############################################################
+show binary logs;
+Log_name	File_size
+master-bin.000001	#
+CREATE TABLE t1 (a int primary key auto_increment, b blob);
+flush logs;
+show binary logs;
+Log_name	File_size
+master-bin.000006	#
+master-bin.000007	#
+DROP TABLE t1;
+reset master;
+##############################################################
+testing purge binary logs to max number on implicit flush
+i.e. when starting new file
+##############################################################
+show binary logs;
+Log_name	File_size
+master-bin.000001	#
+CREATE TABLE t1 (a int primary key auto_increment, b blob);
+show binary logs;
+Log_name	File_size
+master-bin.000005	#
+master-bin.000006	#
+DROP TABLE t1;
+reset master;
+End of tests

=== added file 'Percona-Server/mysql-test/suite/binlog/t/percona_binlog_max_nr-master.opt'
--- Percona-Server/mysql-test/suite/binlog/t/percona_binlog_max_nr-master.opt	1970-01-01 00:00:00 +0000
+++ Percona-Server/mysql-test/suite/binlog/t/percona_binlog_max_nr-master.opt	2012-08-13 05:37:06 +0000
@@ -0,0 +1,2 @@
+--max-binlog-size=4096 --max-binlog-files=2
+

=== added file 'Percona-Server/mysql-test/suite/binlog/t/percona_binlog_max_nr.test'
--- Percona-Server/mysql-test/suite/binlog/t/percona_binlog_max_nr.test	1970-01-01 00:00:00 +0000
+++ Percona-Server/mysql-test/suite/binlog/t/percona_binlog_max_nr.test	2012-08-13 05:37:06 +0000
@@ -0,0 +1,60 @@
+source include/have_log_bin.inc;
+source include/not_embedded.inc;
+
+RESET MASTER;
+
+let $MYSQLD_DATADIR= `select @@datadir`;
+let $INDEX=$MYSQLD_DATADIR/master-bin.index;
+
+--echo ##############################################################
+--echo testing purge binary logs to max number on explicit FLUSH LOGS
+--echo ##############################################################
+
+source include/show_binary_logs.inc;
+file_exists $MYSQLD_DATADIR/master-bin.000001;
+
+CREATE TABLE t1 (a int primary key auto_increment, b blob);
+--disable_query_log
+let $c=20;
+begin;
+while ($c)
+{
+  eval INSERT INTO t1 (b) values ('0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789'),('0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789'),('0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789'),('0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789'),('0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789'),('0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789'),('0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789'),('0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789'),('0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789'),('0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789');
+  dec $c;
+}
+commit;
+--enable_query_log
+
+flush logs;
+source include/show_binary_logs.inc;
+
+DROP TABLE t1;
+
+reset master;
+
+--echo ##############################################################
+--echo testing purge binary logs to max number on implicit flush
+--echo i.e. when starting new file
+--echo ##############################################################
+
+source include/show_binary_logs.inc;
+file_exists $MYSQLD_DATADIR/master-bin.000001;
+
+CREATE TABLE t1 (a int primary key auto_increment, b blob);
+--disable_query_log
+let $c=20;
+begin;
+while ($c)
+{
+  eval INSERT INTO t1 (b) values ('0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789'),('0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789'),('0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789'),('0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789'),('0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789'),('0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789'),('0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789'),('0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789'),('0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789'),('0123456789012345678901234567890123456789012345678901234567890123456789012345678901234567890123456789');
+  dec $c;
+}
+commit;
+--enable_query_log
+
+source include/show_binary_logs.inc;
+DROP TABLE t1;
+
+reset master;
+
+--echo End of tests

=== added file 'Percona-Server/mysql-test/suite/sys_vars/r/max_binlog_files_basic.result'
--- Percona-Server/mysql-test/suite/sys_vars/r/max_binlog_files_basic.result	1970-01-01 00:00:00 +0000
+++ Percona-Server/mysql-test/suite/sys_vars/r/max_binlog_files_basic.result	2012-08-13 05:37:06 +0000
@@ -0,0 +1,134 @@
+SET @start_value = @@global.max_binlog_files;
+SELECT @start_value;
+@start_value
+0
+'#--------------------FN_DYNVARS_072_01------------------------#'
+SET @@global.max_binlog_files = 5000;
+SET @@global.max_binlog_files = DEFAULT;
+SELECT @@global.max_binlog_files;
+@@global.max_binlog_files
+0
+'#---------------------FN_DYNVARS_072_02-------------------------#'
+SET @@global.max_binlog_files = @start_value;
+SELECT @@global.max_binlog_files = 0;
+@@global.max_binlog_files = 0
+1
+'#--------------------FN_DYNVARS_072_03------------------------#'
+SET @@global.max_binlog_files = 4;
+SELECT @@global.max_binlog_files;
+@@global.max_binlog_files
+4
+SET @@global.max_binlog_files = 10;
+SELECT @@global.max_binlog_files;
+@@global.max_binlog_files
+10
+SET @@global.max_binlog_files = 10;
+SELECT @@global.max_binlog_files;
+@@global.max_binlog_files
+10
+SET @@global.max_binlog_files = 40;
+SELECT @@global.max_binlog_files;
+@@global.max_binlog_files
+40
+SET @@global.max_binlog_files = 65;
+SELECT @@global.max_binlog_files;
+@@global.max_binlog_files
+65
+'#--------------------FN_DYNVARS_072_04-------------------------#'
+SET @@global.max_binlog_files = -1;
+Warnings:
+Warning	1292	Truncated incorrect max_binlog_files value: '-1'
+SELECT @@global.max_binlog_files;
+@@global.max_binlog_files
+0
+SET @@global.max_binlog_files = 100000000000;
+Warnings:
+Warning	1292	Truncated incorrect max_binlog_files value: '100000000000'
+SELECT @@global.max_binlog_files;
+@@global.max_binlog_files
+102400
+SET @@global.max_binlog_files = 10000.01;
+ERROR 42000: Incorrect argument type to variable 'max_binlog_files'
+SELECT @@global.max_binlog_files;
+@@global.max_binlog_files
+102400
+SET @@global.max_binlog_files = -1024;
+Warnings:
+Warning	1292	Truncated incorrect max_binlog_files value: '-1024'
+SELECT @@global.max_binlog_files;
+@@global.max_binlog_files
+0
+SET @@global.max_binlog_files = 1024;
+SELECT @@global.max_binlog_files;
+@@global.max_binlog_files
+1024
+SET @@global.max_binlog_files = 4294967296;
+Warnings:
+Warning	1292	Truncated incorrect max_binlog_files value: '4294967296'
+SELECT @@global.max_binlog_files;
+@@global.max_binlog_files
+102400
+SET @@global.max_binlog_files = 4095;
+SELECT @@global.max_binlog_files;
+@@global.max_binlog_files
+4095
+SET @@global.max_binlog_files = ON;
+ERROR 42000: Incorrect argument type to variable 'max_binlog_files'
+SELECT @@global.max_binlog_files;
+@@global.max_binlog_files
+4095
+SET @@global.max_binlog_files = 'test';
+ERROR 42000: Incorrect argument type to variable 'max_binlog_files'
+SELECT @@global.max_binlog_files;
+@@global.max_binlog_files
+4095
+'#-------------------FN_DYNVARS_072_05----------------------------#'
+SET @@session.max_binlog_files = 4096;
+ERROR HY000: Variable 'max_binlog_files' is a GLOBAL variable and should be set with SET GLOBAL
+SELECT @@session.max_binlog_files;
+ERROR HY000: Variable 'max_binlog_files' is a GLOBAL variable
+'#----------------------FN_DYNVARS_072_06------------------------#'
+SELECT @@global.max_binlog_files = VARIABLE_VALUE 
+FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES 
+WHERE VARIABLE_NAME='max_binlog_files';
+@@global.max_binlog_files = VARIABLE_VALUE
+1
+SELECT @@max_binlog_files = VARIABLE_VALUE 
+FROM INFORMATION_SCHEMA.SESSION_VARIABLES 
+WHERE VARIABLE_NAME='max_binlog_files';
+@@max_binlog_files = VARIABLE_VALUE
+1
+'#---------------------FN_DYNVARS_072_07----------------------#'
+SET @@global.max_binlog_files = TRUE;
+SELECT @@global.max_binlog_files;
+@@global.max_binlog_files
+1
+SET @@global.max_binlog_files = FALSE;
+SELECT @@global.max_binlog_files;
+@@global.max_binlog_files
+0
+'#---------------------FN_DYNVARS_072_08----------------------#'
+SET @@global.max_binlog_files = 5000;
+SELECT @@max_binlog_files = @@global.max_binlog_files;
+@@max_binlog_files = @@global.max_binlog_files
+1
+'#---------------------FN_DYNVARS_072_09----------------------#'
+SET max_binlog_files = 6000;
+ERROR HY000: Variable 'max_binlog_files' is a GLOBAL variable and should be set with SET GLOBAL
+SELECT @@max_binlog_files;
+@@max_binlog_files
+5000
+SET local.max_binlog_files = 7000;
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'max_binlog_files = 7000' at line 1
+SELECT local.max_binlog_files;
+ERROR 42S02: Unknown table 'local' in field list
+SET global.max_binlog_files = 8000;
+ERROR 42000: You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 'max_binlog_files = 8000' at line 1
+SELECT global.max_binlog_files;
+ERROR 42S02: Unknown table 'global' in field list
+SELECT max_binlog_files = @@session.max_binlog_files;
+ERROR 42S22: Unknown column 'max_binlog_files' in 'field list'
+SET @@global.max_binlog_files = @start_value;
+SELECT @@global.max_binlog_files;
+@@global.max_binlog_files
+0

=== added file 'Percona-Server/mysql-test/suite/sys_vars/t/max_binlog_files_basic.test'
--- Percona-Server/mysql-test/suite/sys_vars/t/max_binlog_files_basic.test	1970-01-01 00:00:00 +0000
+++ Percona-Server/mysql-test/suite/sys_vars/t/max_binlog_files_basic.test	2012-08-13 05:37:06 +0000
@@ -0,0 +1,147 @@
+--source include/load_sysvars.inc
+#test max-binlog-files, mostly copied from max_binlog_files test
+
+SET @start_value = @@global.max_binlog_files;
+SELECT @start_value;
+
+
+--echo '#--------------------FN_DYNVARS_072_01------------------------#'
+##################################################################
+#           Display the DEFAULT value of max_binlog_files         #
+##################################################################
+
+SET @@global.max_binlog_files = 5000;
+SET @@global.max_binlog_files = DEFAULT;
+SELECT @@global.max_binlog_files;
+
+--echo '#---------------------FN_DYNVARS_072_02-------------------------#'
+############################################### 
+#     Verify default value of variable        #
+############################################### 
+
+SET @@global.max_binlog_files = @start_value;
+SELECT @@global.max_binlog_files = 0;
+
+--echo '#--------------------FN_DYNVARS_072_03------------------------#'
+##################################################################
+#    Change the value of max_binlog_files to a valid value        #
+##################################################################
+
+SET @@global.max_binlog_files = 4;
+SELECT @@global.max_binlog_files;
+SET @@global.max_binlog_files = 10;
+SELECT @@global.max_binlog_files;
+SET @@global.max_binlog_files = 10;
+SELECT @@global.max_binlog_files;
+SET @@global.max_binlog_files = 40;
+SELECT @@global.max_binlog_files;
+SET @@global.max_binlog_files = 65;
+SELECT @@global.max_binlog_files;
+
+
+--echo '#--------------------FN_DYNVARS_072_04-------------------------#'
+#####################################################################
+#      Change the value of max_binlog_files to invalid value         #
+#####################################################################
+
+SET @@global.max_binlog_files = -1;
+SELECT @@global.max_binlog_files;
+SET @@global.max_binlog_files = 100000000000;
+SELECT @@global.max_binlog_files;
+--Error ER_WRONG_TYPE_FOR_VAR
+SET @@global.max_binlog_files = 10000.01;
+SELECT @@global.max_binlog_files;
+SET @@global.max_binlog_files = -1024;
+SELECT @@global.max_binlog_files;
+SET @@global.max_binlog_files = 1024;
+SELECT @@global.max_binlog_files;
+SET @@global.max_binlog_files = 4294967296;
+SELECT @@global.max_binlog_files;
+SET @@global.max_binlog_files = 4095;
+SELECT @@global.max_binlog_files;
+
+--Error ER_WRONG_TYPE_FOR_VAR
+SET @@global.max_binlog_files = ON;
+SELECT @@global.max_binlog_files;
+--Error ER_WRONG_TYPE_FOR_VAR
+SET @@global.max_binlog_files = 'test';
+SELECT @@global.max_binlog_files;
+
+
+--echo '#-------------------FN_DYNVARS_072_05----------------------------#'
+##################################################################### 
+#       Test if accessing session max_binlog_files gives error       #
+#####################################################################
+
+--Error ER_GLOBAL_VARIABLE
+SET @@session.max_binlog_files = 4096;
+--Error ER_INCORRECT_GLOBAL_LOCAL_VAR
+SELECT @@session.max_binlog_files;
+
+
+--echo '#----------------------FN_DYNVARS_072_06------------------------#'
+############################################################################## 
+# Check if the value in GLOBAL & SESSION Tables matches values in variable   #
+##############################################################################
+
+SELECT @@global.max_binlog_files = VARIABLE_VALUE 
+FROM INFORMATION_SCHEMA.GLOBAL_VARIABLES 
+WHERE VARIABLE_NAME='max_binlog_files';
+
+SELECT @@max_binlog_files = VARIABLE_VALUE 
+FROM INFORMATION_SCHEMA.SESSION_VARIABLES 
+WHERE VARIABLE_NAME='max_binlog_files';
+
+
+--echo '#---------------------FN_DYNVARS_072_07----------------------#'
+################################################################### 
+#      Check if TRUE and FALSE values can be used on variable     #
+################################################################### 
+
+SET @@global.max_binlog_files = TRUE;
+SELECT @@global.max_binlog_files;
+SET @@global.max_binlog_files = FALSE;
+SELECT @@global.max_binlog_files;
+
+
+--echo '#---------------------FN_DYNVARS_072_08----------------------#'
+########################################################################################################
+#    Check if accessing variable with SESSION,LOCAL and without SCOPE points to same session variable  #
+########################################################################################################
+
+SET @@global.max_binlog_files = 5000;
+SELECT @@max_binlog_files = @@global.max_binlog_files;
+
+
+--echo '#---------------------FN_DYNVARS_072_09----------------------#'
+##########################################################################
+#   Check if max_binlog_files can be accessed with and without @@ sign    #
+##########################################################################
+
+--Error ER_GLOBAL_VARIABLE
+SET max_binlog_files = 6000;
+SELECT @@max_binlog_files;
+--Error ER_PARSE_ERROR
+SET local.max_binlog_files = 7000;
+--Error ER_UNKNOWN_TABLE
+SELECT local.max_binlog_files;
+--Error ER_PARSE_ERROR
+SET global.max_binlog_files = 8000;
+--Error ER_UNKNOWN_TABLE
+SELECT global.max_binlog_files;
+--Error ER_BAD_FIELD_ERROR
+SELECT max_binlog_files = @@session.max_binlog_files;
+
+
+##############################  
+#   Restore initial value    #
+##############################
+
+SET @@global.max_binlog_files = @start_value;
+SELECT @@global.max_binlog_files;
+
+
+##################################################################
+#              END OF max_binlog_files TESTS                      #
+##################################################################
+

=== modified file 'Percona-Server/sql/log.cc'
--- Percona-Server/sql/log.cc	2012-08-07 06:10:00 +0000
+++ Percona-Server/sql/log.cc	2012-08-13 05:37:06 +0000
@@ -1,4 +1,5 @@
 /* Copyright (c) 2000, 2011, Oracle and/or its affiliates. All rights reserved.
+   Copyright (C) 2012 Percona Inc.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -59,6 +60,8 @@
 
 LOGGER logger;
 
+ulong max_binlog_files;
+
 MYSQL_BIN_LOG mysql_bin_log(&sync_binlog_period);
 
 static bool test_if_number(const char *str,
@@ -4139,6 +4142,74 @@
 }
 
 /**
+  Purge old logs so that we have a maximum of max_nr_files logs.
+
+  @param max_nr_files	Maximum number of logfiles to have
+
+  @note
+    If any of the logs before the deleted one is in use,
+    only purge logs up to this one.
+
+  @retval
+    0				ok
+  @retval
+    LOG_INFO_PURGE_NO_ROTATE	Binary file that can't be rotated
+    LOG_INFO_FATAL              if any other than ENOENT error from
+                                mysql_file_stat() or mysql_file_delete()
+*/
+
+int MYSQL_BIN_LOG::purge_logs_maximum_number(ulong max_nr_files)
+{
+  int error;
+  char to_log[FN_REFLEN];
+  LOG_INFO log_info;
+  ulong current_number_of_logs= 1;
+
+  DBUG_ENTER("purge_logs_maximum_number");
+
+  mysql_mutex_lock(&LOCK_index);
+  to_log[0]= 0;
+
+  if ((error=find_log_pos(&log_info, NullS, 0 /*no mutex*/)))
+    goto err;
+
+  while (!find_next_log(&log_info, 0))
+    current_number_of_logs++;
+
+  if (current_number_of_logs <= max_nr_files)
+  {
+    error= 0;
+    goto err; /* No logs to expire */
+  }
+
+  if ((error=find_log_pos(&log_info, NullS, 0 /*no mutex*/)))
+    goto err;
+
+  while (strcmp(log_file_name, log_info.log_file_name) &&
+	 !is_active(log_info.log_file_name) &&
+	 !log_in_use(log_info.log_file_name) &&
+	 current_number_of_logs > max_nr_files)
+  {
+    current_number_of_logs--;
+    strmake(to_log,
+	    log_info.log_file_name,
+	    sizeof(log_info.log_file_name) - 1);
+
+    if (find_next_log(&log_info, 0))
+    {
+      break;
+    }
+  }
+
+  error= (to_log[0] ? purge_logs(to_log, 1, 0, 1, (ulonglong *) 0) : 0);
+
+err:
+  mysql_mutex_unlock(&LOCK_index);
+  DBUG_RETURN(error);
+}
+
+
+/**
   Remove all logs before the given file date from disk and from the
   index file.
 
@@ -5315,6 +5386,10 @@
       purge_logs_before_date(purge_time);
     }
   }
+  if (max_binlog_files)
+  {
+    purge_logs_maximum_number(max_binlog_files);
+  }
 #endif
 }
 
@@ -5833,7 +5908,7 @@
 
     mysql_mutex_unlock(&LOCK_log);
 
-    if (xid_count > 0 && check_purge)
+    if (xid_count == 0 && check_purge)
     {
       purge();
     }

=== modified file 'Percona-Server/sql/log.h'
--- Percona-Server/sql/log.h	2012-08-07 06:10:00 +0000
+++ Percona-Server/sql/log.h	2012-08-13 05:37:06 +0000
@@ -569,6 +569,7 @@
   int purge_logs(const char *to_log, bool included,
                  bool need_mutex, bool need_update_threads,
                  ulonglong *decrease_log_space);
+  int purge_logs_maximum_number(ulong max_nr_files);
   int purge_logs_before_date(time_t purge_time);
   int purge_first_log(Relay_log_info* rli, bool included);
   int set_purge_index_file_name(const char *base_file_name);

=== modified file 'Percona-Server/sql/mysqld.cc'
--- Percona-Server/sql/mysqld.cc	2012-08-07 06:10:00 +0000
+++ Percona-Server/sql/mysqld.cc	2012-08-13 05:37:06 +0000
@@ -4151,6 +4151,10 @@
     if (purge_time >= 0)
       mysql_bin_log.purge_logs_before_date(purge_time);
   }
+  if (opt_bin_log && max_binlog_files)
+  {
+    mysql_bin_log.purge_logs_maximum_number(max_binlog_files);
+  }
 #endif
 
   if (opt_myisam_log)

=== modified file 'Percona-Server/sql/mysqld.h'
--- Percona-Server/sql/mysqld.h	2012-08-07 06:10:00 +0000
+++ Percona-Server/sql/mysqld.h	2012-08-13 05:37:06 +0000
@@ -142,6 +142,7 @@
 extern ulong max_long_data_size;
 extern ulong current_pid;
 extern ulong expire_logs_days;
+extern ulong max_binlog_files;
 extern my_bool relay_log_recovery;
 extern uint sync_binlog_period, sync_relaylog_period, 
             sync_relayloginfo_period, sync_masterinfo_period;

=== modified file 'Percona-Server/sql/sys_vars.cc'
--- Percona-Server/sql/sys_vars.cc	2012-08-07 06:10:00 +0000
+++ Percona-Server/sql/sys_vars.cc	2012-08-13 05:37:06 +0000
@@ -799,6 +799,14 @@
        GLOBAL_VAR(expire_logs_days),
        CMD_LINE(REQUIRED_ARG), VALID_RANGE(0, 99), DEFAULT(0), BLOCK_SIZE(1));
 
+static Sys_var_ulong Sys_max_binlog_files(
+       "max_binlog_files",
+       "Maximum number of binlog files. Used with --max-binlog-size this can "
+       "be used to limit the total amount of disk space used for the binlog. "
+       "Default is 0, don't limit.",
+       GLOBAL_VAR(max_binlog_files),
+       CMD_LINE(REQUIRED_ARG), VALID_RANGE(0, 102400), DEFAULT(0), BLOCK_SIZE(1));
+
 static Sys_var_mybool Sys_flush(
        "flush", "Flush MyISAM tables to disk between SQL commands",
        GLOBAL_VAR(myisam_flush),