[rt-users] Slow Ticket History 3.8.8

[Justin Hayes]

As a test we've just created a long ticket in an empty RT DB and it's very fast. So does look to be DB related - contrary to our earlier investigations.

I guess it must still access the DB resultset during the ticket rendering (which isn't how we thought it would work).

Time to tune the hell out of mysql then.......

Justin

-------------------------------------------------
Justin Hayes
OpenBet Support Manager
justin.hayes at openbet.com

On 29 Jun 2010, at 15:53, Justin Hayes wrote:

> Seem to be quite a few things to look at Jason. Need to figure out what they all mean first.
> 
> Justin
> 
> -------- General Statistics --------------------------------------------------
> [--] Skipped version check for MySQLTuner script
> [OK] Currently running supported MySQL version 5.1.37-1ubuntu5.4-log
> [OK] Operating on 64-bit architecture
> 
> -------- Storage Engine Statistics -------------------------------------------
> [--] Status: -Archive -BDB -Federated +InnoDB -ISAM -NDBCluster 
> [--] Data in MyISAM tables: 611M (Tables: 8)
> [--] Data in InnoDB tables: 10G (Tables: 20)
> [!!] Total fragmented tables: 21
> 
> -------- Performance Metrics -------------------------------------------------
> [--] Up for: 19d 19h 32m 37s (110M q [64.266 qps], 222K conn, TX: 637B, RX: 39B)
> [--] Reads / Writes: 98% / 2%
> [--] Total buffers: 602.0M global + 134.8M per thread (150 max threads)
> [!!] Maximum possible memory usage: 20.3G (262% of installed RAM)
> [OK] Slow queries: 0% (229K/110M)
> [!!] Highest connection usage: 100%  (151/150)
> [OK] Key buffer size / total MyISAM indexes: 512.0M/6.7M
> [OK] Key buffer hit rate: 100.0% (84M cached / 7K reads)
> [OK] Query cache efficiency: 71.4% (76M cached / 107M selects)
> [!!] Query cache prunes per day: 661360
> [OK] Sorts requiring temporary tables: 0% (0 temp sorts / 2M sorts)
> [!!] Joins performed without indexes: 112714
> [!!] Temporary tables created on disk: 33% (968K on disk / 2M total)
> [OK] Thread cache hit rate: 99% (1K created / 222K connections)
> [OK] Table cache hit rate: 36% (318 open / 880 opened)
> [OK] Open file limit used: 14% (166/1K)
> [OK] Table locks acquired immediately: 99% (39M immediate / 39M locks)
> [!!] InnoDB data size / buffer pool: 10.1G/8.0M
> 
> -------- Recommendations -----------------------------------------------------
> General recommendations:
>    Run OPTIMIZE TABLE to defragment tables for better performance
>    Reduce your overall MySQL memory footprint for system stability
>    Reduce or eliminate persistent connections to reduce connection usage
>    Adjust your join queries to always utilize indexes
>    When making adjustments, make tmp_table_size/max_heap_table_size equal
>    Reduce your SELECT DISTINCT queries without LIMIT clauses
> Variables to adjust:
>  *** MySQL's maximum memory usage is dangerously high ***
>  *** Add RAM before increasing MySQL buffer variables ***
>    max_connections (> 150)
>    wait_timeout (< 28800)
>    interactive_timeout (< 28800)
>    query_cache_size (> 16M)
>    join_buffer_size (> 2.0M, or always use indexes with joins)
>    tmp_table_size (> 128M)
>    max_heap_table_size (> 64M)
>    innodb_buffer_pool_size (>= 10G)
> 
> 
> -------------------------------------------------
> Justin Hayes
> OpenBet Support Manager
> justin.hayes at openbet.com
> 
> On 29 Jun 2010, at 15:22, Jason Doran wrote:
> 
>> Hi,
>> If you are using mysqld have a look at "mysqltuner.pl" perl script (google)
>> This has fixed quickly many performance issues on both RT and other
>> web-based software we use. I run this every few weeks and apply suggested
>> changes and then simply restart mysqld when things are quite.
>> 
>> Regards,
>> Jason Doran
>> Computer Centre
>> NUI, Maynooth
>> 
>> On 29 Jun 2010, at 14:09, Justin Hayes wrote:
>> 
>>> Hi everyone,
>>> 
>>> I've raised this before, but we've had another look at it and still can't see how to improve things.
>>> 
>>> We put a lot of comments/replies in our tickets. Often there can be 50-100 entries in a ticket, mostly plain text. Loading such a ticket can take 10-20secs.
>>> 
>>> We don't have any slow queries - all the time seems to be in the code rendering the history of the ticket.
>>> We've had a go at stripping functions out of ShowHistory, ShowTransaction and ShowTransactionAttachmments but not had much success.
>>> 
>>> FWIW our RT runs on quad 3ghz Xeons with 8gb of ram.
>>> 
>>> I'd like to try and determine if we're just slow, or if this is just how long RT takes. Maybe perl is just slow.
>>> 
>>> Can anyone shed any light on how long it takes them to render long tickets in their systems? If you look at the page source it gives you a value e.g.
>>> 
>>> <span>Time to display: 24.996907</span>
>>> 
>>> Can anyone share some numbers from theirs for longer tickets? It would be really appreciated.
>>> 
>>> 
>>> Thanks,
>>> 
>>> Justin
>>> 
>>> -------------------------------------------------
>>> Justin Hayes
>>> OpenBet Support Manager
>>> justin.hayes at openbet.com
>>> 
>>> 
>>> Discover RT's hidden secrets with RT Essentials from O'Reilly Media.
>>> Buy a copy at http://rtbook.bestpractical.com
>> 
> 
> 
> Discover RT's hidden secrets with RT Essentials from O'Reilly Media.
> Buy a copy at http://rtbook.bestpractical.com