pt-query-digest --processlist reports duplicate queries for replication thread

Reported by Nickolay Ihalainen on 2013-03-18
8
This bug affects 1 person
Affects Status Importance Assigned to Milestone
Percona Toolkit
Medium
Brian Fraser

Bug Description

pt-query-digest --processlist can't merge correctly show full processlist outputs for slave thread. As a result wrong queries could be listed in a report.

percona toolkit 2.1.8 and 2.1.5 versions are affected.

/usr/local/sbin/pt-query-digest --interval 0.2 --filter '$event->{Query_time} > 1' --processlist h=SERVER,u=USER -p PASSWORD --print --no-report --run-time 3600 > logs/SERVER-`date +%Y%m%d-%H`

Replication thread can't execute two queries in parallel at the same time:

 Processlist:2417 25797 Polling PROCESSLIST
# Processlist:2428 25797 Rows: 3 in 0.000298976898193359 seconds
# Processlist:2488 25797 New cxn 166
# Processlist:2442 25797 Checking existing cxn 167
# Processlist:2458 25797 Query restarted; new query 1363226464.1831 0.000298976898193359 1363226463 1
# Processlist:2565 25797 Query is still in Repair by sorting state
# Processlist:2547 25797 Properties of event: $VAR1 = {
# Lock_time => 0,
# Query_time => 21,
# arg => 'OPTIMIZE TABLE t',
# bytes => 46,
# db => 't',
# host => '',
# id => 167,
# ts => '2013-03-14T02:01:24',
# user => 'system user'
# };

# Processlist:2417 25797 Polling PROCESSLIST
# Processlist:2428 25797 Rows: 3 in 0.000288009643554688 seconds
# Processlist:2488 25797 New cxn 166
# Processlist:2442 25797 Checking existing cxn 167
# Processlist:2449 25797 Info is different; new query
# Processlist:2569 25797 Query changed from state Sorting index to undef
# Processlist:2547 25797 Properties of event: $VAR1 = {
# Lock_time => 0,
# Query_time => 21,
# arg => 'OPTIMIZE TABLE t',
# bytes => 46,
# db => 't',
# host => '',
# id => 167,
# ts => '2013-03-14T02:01:25',
# user => 'system user'
# };

description: updated
Daniel Nichter (daniel-nichter) wrote :

I think there's another bug about this, basically that pt-query-digest --processlist thinks a new event has happened when the same process's state has changed, so really it's the same event.

Changed in percona-toolkit:
status: New → Confirmed
milestone: none → 2.2.2
tags: added: percona-29132
removed: i29132
Changed in percona-toolkit:
importance: Undecided → Medium
assignee: nobody → Brian Fraser (fraserbn)
Brian Fraser (fraserbn) on 2013-04-16
Changed in percona-toolkit:
status: Confirmed → Fix Committed
summary: - pt-query-digest --processlist: Duplicate entries for replication thread
+ pt-query-digest --processlist reports duplicate queries for replication
+ thread
Changed in percona-toolkit:
status: Fix Committed → Fix Released
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