[ZODB-Dev] slow page requests using relstorage with mysql

[Dylan Jay]

Hi,

I'm not sure if this is a bug or a misconfiguration but I'm getting some really slow page generation times. I profiled it and a lot of time is spent in rollback which seemed odd.

 Ordered by: internal time
   List reduced from 2017 to 100 due to restriction <100>

Function                                                                           was called by...
                                                                                       ncalls  tottime  cumtime
{method 'rollback' of '_mysql.connection' objects}                                 <-     148    3.642    3.642  connmanager.py:89(restart_load)
                                                                                          147    3.613    3.613  storage.py:230(_rollback_load_connection)
transform.py:149(transformIterable)                                                <-      40    6.470    6.478  transformer.py:24(__call__)
{method 'query' of '_mysql.connection' objects}                                    <-     148    3.661    3.661  cursors.py:277(_do_query)
...

The page itself is just a normal page, no writes involved. The mysql server is replicated master-slave.



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Dylan Jay
Technical Solutions Manager
PretaWeb: Multisite Performance Support
P: +612 80819071 | M: +61421477460 | twitter.com/pretaweb | linkedin.com/in/djay75