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Bug 81378

Summary: memlock option not working
Product: [Retired] Red Hat Linux Reporter: Ion Badulescu <ionut>
Component: mysqlAssignee: Tom Lane <tgl>
Status: CLOSED UPSTREAM QA Contact: David Lawrence <dkl>
Severity: medium Docs Contact:
Priority: medium    
Version: 7.3CC: hhorak
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Hardware: All   
OS: Linux   
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Fixed In Version: Doc Type: Bug Fix
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Last Closed: 2004-02-03 18:35:30 UTC Type: ---
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oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
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Description Flags
fix for memlock problem none

Description Ion Badulescu 2003-01-08 16:52:54 UTC
From Bugzilla Helper:
User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.0.1) Gecko/20021003

Description of problem:
If the mysql daemon is runing as a non-root user, it calls mlockall() after
switching uid's and consequently it fails to lock itself into memory.

All mysql versions are affected, from rh72 through rawhide.

The patch I'm attaching is against 3.23.54a (rawhide). It may not be the ideal
fix, but it is obviously correct and works for me.


Version-Release number of selected component (if applicable):


How reproducible:
Always

Steps to Reproduce:
1. add "memlock" to the [mysqld] section in /etc/my.cnf
2. start mysqld
3. check its memlocked status (the L flag in the "ps ax" output)
    

Actual Results:  11958 pts/0    S      0:01  \_ /usr/libexec/mysqld


Expected Results:  12228 pts/0    SL     0:02  \_ /usr/libexec/mysqld


Additional info:

Non-working memlock causes mysqld to get paged out occassionally, with the
expected negative effects on performance.

Comment 1 Ion Badulescu 2003-01-08 16:54:18 UTC
Created attachment 89216 [details]
fix for memlock problem

Comment 2 Tom Lane 2004-02-03 18:35:30 UTC
Since this is a fairly noncritical issue, I don't think we should
maintain a private fix for it.  The bug should be filed upstream, that
is with MySQL AB.  (A quick look suggests that the issue is still
present in MySQL 4.0.17.)