Re: Serious OutOfMemory issue while reading with mysql-connector-j-5.0.7 ...

A.J. Blanchard (ajblanch) schrieb:
> Hum,
>
> I had this problem long ago on a much older version of drivers/engine. It amounted to the client side trying to read in the entire ResultsSet into the local JVM. Turned out we had to limit the ResultSet size to 30,000 some odd size to prevent the OOM Exception (LIMIT). 
>
> Recently, we have been able to at least get the row count and seems the data was streaming. We did nothing special (in options) to achieve this. But that was pre-5.x. I have not run this specific test lately. 
>
> Just to see if you can avoid the OOM, try LIMIT and heap up with the popular -Xmx512M (if I recall the syntax correctly).  
>
> A. J.
>   
Thanks for your feedback. I'll try some 3.x drivers ... I've tried to 
avoid that, since 5.x drivers handled several things like stmt.cancel() 
or meta data character enconding better, but we still have the work 
arounds in our database abstraction layer.

The exception occured with a table that has 200+ columns and ~3 mio 
records. Sure, if we read less data or add more memory, it will work 
somehow - but then, what's the point in using mysql as database at all, 
if it's driver can not handle data?

Adding memory is not an option. The application is a datawarehouse which 
runs on many platforms and is highly optimized. I mean it has a lot real 
good optimizations regarding speed and memory footprint. Under load it 
usually uses only 32-64M - so I definitely won't add 512mb to that to 
get troubles with our customers and encounter another exception with 6 
mio recs.

@Mark/MySQL .. has anyone already looked at the issue? what's the status?

Best regards
Paul

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