| Bug #50225 | rpl_backup_shutdown reveals memory issue in backup code | ||
|---|---|---|---|
| Submitted: | 11 Jan 2010 10:57 | Modified: | 14 Jan 2010 7:26 |
| Reporter: | Andrei Elkin | Email Updates: | |
| Status: | Patch queued | Impact on me: | |
| Category: | MySQL Server: Backup | Severity: | S3 (Non-critical) |
| Version: | OS: | Any | |
| Assigned to: | Rafal Somla | CPU Architecture: | Any |
[11 Jan 2010 10:57]
Andrei Elkin
[12 Jan 2010 16:46]
Rafal Somla
I was able to reproduce symptoms with the following test case: --------------------------------------------------------------- CREATE DATABASE db1; CREATE TABLE db1.t1 (a int); CREATE TRIGGER db1.r1 AFTER INSERT ON db1.t1 FOR EACH ROW SET @foo=1; BACKUP DATABASE db1 TO 'db1.bak'; --echo --> Stop the server ... --write_file $MYSQLTEST_VARDIR/tmp/mysqld.1.expect wait EOF --shutdown_server 10 --source include/wait_until_disconnected.inc --echo --> Restart the server ... --append_file $MYSQLTEST_VARDIR/tmp/mysqld.1.expect restart EOF --enable_reconnect --source include/wait_until_connected_again.inc --echo --> Cleanup ... DROP DATABASE db1; --exit --------------------------------------------------------------- It means that issue is not related to replication. I observe memory leak only if server is stopped and restarted - if these lines are commented-out then no leak is reported. Also, one needs to backup a trigger to get memory leak.
[12 Jan 2010 16:48]
Rafal Somla
When I run the above test script in valgrind mode I see the following stacks: ==8209== ==8209== 16 bytes in 2 blocks are indirectly lost in loss record 1 of 7 ==8209== at 0x4023D6E: malloc (vg_replace_malloc.c:207) ==8209== by 0x85DB900: my_malloc (my_malloc.c:37) ==8209== by 0x82755FC: String::real_alloc(unsigned) (sql_string.cc:52) ==8209== by 0x81EF790: String::alloc(unsigned) (sql_string.h:209) ==8209== by 0x8275885: String::copy(char const*, unsigned, charset_info_st*) (sql_string.cc:212) ==8209== by 0x847FAC6: obs::Abstract_obj::Abstract_obj(st_mysql_lex_string, bool) (si_objects.cc:679) ==8209== by 0x847FC23: obs::Database_item_obj::Database_item_obj(st_mysql_lex_string, st_mysql_lex_string, bool) (si_objects.cc:929) ==8209== by 0x847FD80: obs::Table_obj::Table_obj(st_mysql_lex_string, st_mysql_lex_string) (si_objects.cc:983) ==8209== by 0x847CE06: obs::find_table_for_trigger(THD*, String const*, String const*) (si_objects.cc:3203) ==8209== by 0x86B3589: Backup_info::add_db_object(backup::Image_info::Db&, enum_bstream_item_type, obs::Obj*) (backup_info.cc:1384) ==8209== by 0x86B3BA9: Backup_info::add_objects(backup::Image_info::Db&, enum_bstream_item_type, obs::Obj_iterator&) (backup_info.cc:965) ==8209== by 0x86B58C6: Backup_info::add_db_items(backup::Image_info::Db&) (backup_info.cc:1114) ==8209== by 0x86B5FB4: Backup_info::add_dbs(THD*, List<st_mysql_lex_string>&) (backup_info.cc:842) ==8209== by 0x869E62B: execute_backup_command(THD*, LEX*, String*, bool, bool) (kernel.cc:242) ==8209== by 0x828E030: mysql_execute_command(THD*) (sql_parse.cc:2455) ==8209== by 0x82959B1: mysql_parse(THD*, char const*, unsigned, char const**) (sql_parse.cc:5879) ==8209== ==8209== ==8209== 112 (96 direct, 16 indirect) bytes in 1 blocks are definitely lost in loss record 5 of 7 ==8209== at 0x4023D6E: malloc (vg_replace_malloc.c:207) ==8209== by 0x85DC789: operator new(unsigned) (my_new.cc:27) ==8209== by 0x847CDDE: obs::find_table_for_trigger(THD*, String const*, String const*) (si_objects.cc:3203) ==8209== by 0x86B3589: Backup_info::add_db_object(backup::Image_info::Db&, enum_bstream_item_type, obs::Obj*) (backup_info.cc:1384) ==8209== by 0x86B3BA9: Backup_info::add_objects(backup::Image_info::Db&, enum_bstream_item_type, obs::Obj_iterator&) (backup_info.cc:965) ==8209== by 0x86B58C6: Backup_info::add_db_items(backup::Image_info::Db&) (backup_info.cc:1114) ==8209== by 0x86B5FB4: Backup_info::add_dbs(THD*, List<st_mysql_lex_string>&) (backup_info.cc:842) ==8209== by 0x869E62B: execute_backup_command(THD*, LEX*, String*, bool, bool) (kernel.cc:242) ==8209== by 0x828E030: mysql_execute_command(THD*) (sql_parse.cc:2455) ==8209== by 0x82959B1: mysql_parse(THD*, char const*, unsigned, char const**) (sql_parse.cc:5879) ==8209== by 0x8296420: dispatch_command(enum_server_command, THD*, char*, unsigned) (sql_parse.cc:1071) ==8209== by 0x82976A7: do_command(THD*) (sql_parse.cc:755) ==8209== by 0x82859B3: handle_one_connection (sql_connect.cc:1163) ==8209== by 0x402CF3A: start_thread (pthread_create.c:297) ==8209== by 0x417DBED: clone (in /usr/lib/debug/libc-2.7.so)
[12 Jan 2010 16:58]
Rafal Somla
REFINED PROBLEM DESCRIPTION --------------------------- Si_objects function obs::find_table_for_trigger() returns a pointer to an obs::Obj instance which should be freed by the caller of this function. However, in function Backup_info::add_db_object() the instance returned by obs::find_table_for_trigger() is not freed (backup_info.cc:1383) leading to memory leak. I don't know why valgrind detects this only when server is shut down and restarted.
[12 Jan 2010 17:54]
Bugs System
A patch for this bug has been committed. After review, it may be pushed to the relevant source trees for release in the next version. You can access the patch from: http://lists.mysql.com/commits/96655 3056 Rafal Somla 2010-01-12 Bug #50225 - rpl_backup_shutdown reveals memory issue in backup code Ensure that object returned by obs::find_table_for_trigger() is always deleted. @ sql/backup/backup_info.cc Delete tbl_obj instance returned by obs::find_table_for_trigger(). @ sql/si_objects.cc Add note that object returned by find_table_for_trigger() must be deleted by caller.
[12 Jan 2010 19:25]
Chuck Bell
Approved
[13 Jan 2010 13:39]
Bugs System
A patch for this bug has been committed. After review, it may be pushed to the relevant source trees for release in the next version. You can access the patch from: http://lists.mysql.com/commits/96766 3061 Rafal Somla 2010-01-13 Bug #50225 - rpl_backup_shutdown reveals memory issue in backup code Ensure that object returned by obs::find_table_for_trigger() is always deleted. @ sql/backup/backup_info.cc Delete tbl_obj instance returned by obs::find_table_for_trigger(). @ sql/si_objects.cc Add note that object returned by find_table_for_trigger() must be deleted by caller.
[14 Jan 2010 7:26]
Rafal Somla
Queued into mysql-backup-backport tree. revision-id:rafal.somla@sun.com-20100113133815-ab8mwj09uzwovef4
