[MonetDB-users] Memory leaks on nightly stable

m h sesquile at gmail.com
Fri Dec 21 21:29:48 CET 2007

Hey all-

I've been benchmarking my application against mysql and postgres.

For my test application which has some 1Mil rows of data and my sample
query that returns some 260K rows here's some stats.

Speed for query:

Postgres 15 sec (8.1)
Monetdb 33 sec (nightly stable)
Mysql 100 sec (5.0)

Bulk load speed:

Postgres 12 Min
Monetdb 1 Min
Mysql 2 Min

Memory during bulk load:
Postgres 20 Meg
Monetdb 700 Meg!!! (And it doesn't come back down)
Mysql 20 Meg

Memory during query:
Postgres 30Meg
Monetdb 180 Meg (And increases by 10-20 Meg /query)
Mysql 30 Meg

Niels has some trick up his sleeves that bring the query speed down
(using the nightly current).  But I'm concerned about memory use.
It's fine to use memory if you are going to be fast.  But if I can't
load my data (in all I have 67+ mil rows) or have to restart the
server after a few queries it is problematic.

I've submitted bugs with valgrind reports during load/query, but am
wondering if other steps can be taken to help with the memory issue?

I know that both mysql and postgres (and a host of other open source
projects) have benefitted from coverity's offering [0]
and klocworks [1] as well.  Have these been looked into?  It might be
worth it have some automated "eyes" along with the "many eyes" of the
open source community that make all bugs shallow.

Some food for thought



0 - http://scan.coverity.com/
1 - http://www.klocwork.com/company/releases/06_26_06.asp

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