mysql client aborts connection on terminal resize

Bug #925343 reported by ViNiL on 2012-02-02
This bug affects 7 people
Affects Status Importance Assigned to Milestone
MySQL Server
Percona Server moved to
Fix Released
Sergei Glushchenko
Fix Released
Sergei Glushchenko
Fix Released
Sergei Glushchenko

Bug Description

While running various sql scripts we hit "Lost connection to MySQL server during query" frequently.
Have tried both, network and unix socket for connection => same result. We have increased all timeout variables as well.

We use mysqld_multi for multiple percona installs.
OS: CentOS 6

The database itself is quite large: 72G (du -sh)
All "InnoDB" tables.

socket = /var/lib/mysql-db/mysql.sock
port = 3311
datadir = /var/lib/mysql-db
max_connections = 300
innodb_buffer_pool_size = 10G
query_cache_size = 500M
log-bin = server-db-bin
relay-log = server-db-relay-bin
log_slow_queries = server-db-slow.log
long_query_time = 5
expire_logs_days = 7
binlog_format = MIXED

basedir = /usr
datadir = /var/lib/mysql
port = 3306
socket = /var/lib/mysql/mysql.sock
max_allowed_packet = 64M
table_cache = 2048
max_heap_table_size = 256M
tmp_table_size = 256M
join_buffer_size = 3M
sort_buffer_size = 4M
read_buffer_size = 1M
read_rnd_buffer_size = 1M
myisam_sort_buffer_size = 64M
thread_cache_size = 256
query_cache_limit = 4M
low_priority_updates = 1
innodb_log_file_size = 512M
innodb_flush_log_at_trx_commit = 2
innodb_log_buffer_size = 8M
innodb_thread_concurrency = 16
innodb_flush_method = O_DIRECT
innodb_file_per_table = 1
server-id = 10
old_passwords = 1
character-set-server = utf8
net_read_timeout = 240
net_write_timeout = 240
connect_timeout = 240
tmpdir = /data/mysqltmp/

mysqld = /usr/bin/mysqld_safe
mysqladmin = /usr/bin/mysqladmin
log = /var/log/mysqld_multi.log

Any hint on what is going wrong here? The frequent "lost connection" makes any db upgrade process very painful.
We have not seen this issue before, using vanilla mysql 5.0 and 5.1.

Related branches

Alexey Kopytov (akopytov) wrote :

Might be related to bug #805805. Any chance that gdb or strace are being used against the server process when this issue occurs?

ViNiL (vinil) wrote :

I'll try when this occurs on our test db.

Do you have any specific command or cookbook I should try?

Alexey Kopytov (akopytov) wrote :

I meant to say it is a known issue that clients get disconnected when gdb or strace is attached to the server, which has been reported as bug #805805. So I'm wondering if you are using some monitoring tools like pt-pmp or pt-stalk, or running gdb/strace manually. In which case it would most likely be a duplicate of bug #805805.

ViNiL (vinil) wrote :

Ah, I see.
No, we are not running gdb, nor strace. The only way we monitor the database is via mysql client (ie. nagios / check_mysql_health)

Stewart Smith (stewart) on 2012-02-07
Changed in percona-server:
importance: Undecided → Medium
Ryan Brothers (ryan-brothers) wrote :

I am running into a similar issue that I just described here - not sure if it is related:

Jervin R (revin) wrote :

@ViNiL @Ryan - how are you guys running your scripts? This could be a bug with the mysql client I reported before although it should also be reproduceable upstream

Ryan Brothers (ryan-brothers) wrote :

Jervin - thanks so much. That's exactly the problem I'm running into - I can now reproduce it anytime. I am running putty on Windows connecting to a CentOS machine, and if I resize the putty window while the query is running, I get the error "Lost connection to MySQL server during query" every single time. I can only reproduce though using Percona 5.5.27-28.1. I just tried it with MySQL 5.5.27 from and I cannot reproduce it.

Alexey Kopytov (akopytov) wrote :

This is most likely a regression introduced upstream in 5.5 with the fix for

Alexey Kopytov (akopytov) wrote :

Bug #1055641 was marked as a duplicate of this one.

Cannot repeat this with "5.1.65-rel14.0-log".

summary: - Timeouts during long running scripts
+ mysql client aborts connection on terminal resize

Also, I tested this on mysql/percona server 55 built with system readline than the bundled libedit (with -DWITH_READLINE=ON ) and it is not aborting from SIGWINCH.

Jervin R (revin) wrote :

This is still repeatable on binary release of PS 5.5.30.

tags: added: i30462
Przemek (pmalkowski) wrote :

I can confirm the bug still happening in binary release of Percona Server version 5.5.30, but it's fixed in 5.5.31 and 5.5.32.

Sergei -

Please consider submitting your patch under OCA to Oracle. See the upstream bug comments, they are worried about backporting some frameworks from 5.6 to 5.5, maybe they will have comments on this patch.

Percona now uses JIRA for bug reports so this bug report is migrated to:

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