Pyramid, MySQL and Windows: the good (Pyramid), the ugly and the bad. This title does not fit perfectly the main characters of this blog post because some of theme are both ugly and bad, but it doesn't matter.
Just in case you are going to set up a Pyramid project based on MySQL and Windows (sometimes you have to)... there are a couple of things useful to know. But let's start with a chronologically order.
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1 - adjust your my.ini options like that:
4 - [OPTIONAL, not only Windows related] adjust your SqlAlchemy configuration parameters according to how many threads your server runs. For example (production.ini):
Just in case you are going to set up a Pyramid project based on MySQL and Windows (sometimes you have to)... there are a couple of things useful to know. But let's start with a chronologically order.
Day 0 - morning
You feel like the brave Steeve McQueen:
Evening - day 0
At the end of the day you'll feel also like Steeve McQueen, but a little more proved:
What happened?
Random problems with normal transactions considered too large, thread disconnected, error log entries like:- InterfaceError
- OperationalError
- MySQL Server has gone away
- database connection failure
- TimeoutError: QueuePool limit of size ... overflow ... reached, connection timed out, timeout ...
- pyramid process hangs
- etc
The solution
1 - adjust your my.ini options like that:
2 - be sure your production.ini file looks like the following one (with Python 2):[mysqld]
max_allowed_packet = 64MB # adjust this parameter according to your situation
wait_timeout = 28800
interactive_timeout = 2880
sqlalchemy.url = mysql+mysqldb://USER:PASSWORD@127.0.0.1:3306/YOURDB?charset=utf8&use_unicode=03 - you can schedule a restart of your application once a day.
# For Mysql "MySQL Connection Timeout and SQLAlchemy Connection Pool Recycling" issues see:
# http://docs.sqlalchemy.org/en/latest/core/pooling.html#setting-pool-recycle
# http://douglatornell.ca/blog/2012/01/08/staying-alive/
sqlalchemy.pool_recycle = 3600
4 - [OPTIONAL, not only Windows related] adjust your SqlAlchemy configuration parameters according to how many threads your server runs. For example (production.ini):
5 - if you are using CherryPy as a Windows service, be sure your 'engine.autoreload.on' option is set to False.sqlalchemy.pool_size=20
sqlalchemy.max_overflow=10
Results
No more exceptions or odd behaviours!Links
- http://docs.sqlalchemy.org/en/rel_0_9/dialects/mysql.html#unicode-encoding-decoding
- http://docs.sqlalchemy.org/en/rel_0_9/dialects/mysql.html#module-sqlalchemy.dialects.mysql.mysqldb
- http://docs.sqlalchemy.org/en/latest/core/pooling.html#setting-pool-recycle
- http://douglatornell.ca/blog/2012/01/08/staying-alive/