After plenty of querys the database use 40 times more disk space than the original data, How can I avoid this?

Stefan Manegold Stefan.Manegold at cwi.nl
Thu Jun 6 09:26:50 CEST 2013


Hi Jason,

to be able to analyze the problem, we'd need all the information to be able to reproduce it; this includes at least

- exact version of MonetDB
- operating system
- hardware, in particular #hardware threads and size of RAM
(the output of `mserver5 --version` should contain all these)

- database schema and queries
- data; or at least EXPLAIN's and TRACE's of your queries

Preferably, file a bug report with all this information.

Best,
Stefan

----- Original Message -----
> Hi guys:
>        In my case , original data 8G bytes, but after plenty of
>        query, the disk space usage is 361G bytes. The query is
>        simply, first five UNION ALL, then fetch the result. When the
>        query is running, I use vmstat to watch the IO status. When
>        the database becomes larger, the BI and BO number increase
>        very large too, for example  bo 355224, bi 27392. And the
>        query cost ten times longer than before!
>        After rebooting the database, the database disk space was
>        reduced to its original data size, 8G. It seems too much
>        runtime data was produced. How can I solve the problem or
>        avoid the problem!
> 
> Thanks,Jason
> 
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