wangyu190810 / pqc

Automatically exported from code.google.com/p/pqc
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Possible concurrency issue #6

Open GoogleCodeExporter opened 9 years ago

GoogleCodeExporter commented 9 years ago
I'm trying to use pqc with Mapnik and TileCache, which I use to generate custom 
maps. The map data is never changed, so only select queries are executed, which 
makes pqc ideal for this setup. When I begin generating map tiles, many queries 
are executed in succession, and eventually one of the queries will fail with a 
fatal error from postgresql. There's no additional information from the server 
about the failure, and everything from pqc in debug mode looks fine. According 
to pqc, the results of the query were returned appropriately. I can immediately 
generate the tiles again, and it will fail on a different query, so it doesn't 
seem to have anything to do with the query itself. I can even run the queries 
manually from psql and it works.

If I run pqc in passive mode with no caching at all, everything works. I know 
I'm not providing a lot of information to go on, but that's about all I know, 
and I'm out of troubleshooting ideas. I've played around with all the settings 
in memcache, and changed the verbosity to -vvv, but still nothing to go on. The 
queries that usually fail tend to take a while to execute (10 seconds or more). 
Can you think of anything else I could try? Again, I apologize for the lack of 
information, but I'd really appreciate some help. I'm running Ubuntu 12.04, 
postgresql 9.1 and the latest pqc source from github. I can give you any other 
information you need... just let me know.

Thank you.

Original issue reported on code.google.com by jdwillia...@gmail.com on 14 Jul 2012 at 4:50