[Monetdb-developers] MonetDB memory management
Hi, Does anyone has the same memory management problem as me? When I inserted many records like: Insert into tbl1 (id,dt) values(1,blob ‘…………………………………………’); Memory is used up to 1G. That's OK. But when I delete the whole table like: Delete from tbl1; None memory is released, still 1G is used. And when i insert again, memory used keeps increasing. Is this a problem or is it the way MonetDB works? Thx. -- Best Regards, Xiao Lei
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA512 Op 15-04-10 06:06, Xiao Lei schreef:
And when i insert again, memory used keeps increasing.
Is this a problem or is it the way MonetDB works?
I can confirm this behavior. Stefan -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.14 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEAREKAAYFAkvG0wEACgkQYH1+F2Rqwn1YZgCfWAZgDPHatE3bHCSOzV17TjUX 8jEAn1uv7oxq+Qzp+0vb0SlUGJzoVHZn =9y1y -----END PGP SIGNATURE-----
So how can i release the memory when i have already deleted from table
without restarting MonetDB?
2010/4/15 Stefan de Konink
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Op 15-04-10 06:06, Xiao Lei schreef:
And when i insert again, memory used keeps increasing.
Is this a problem or is it the way MonetDB works?
I can confirm this behavior.
Stefan -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.14 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/
iEYEAREKAAYFAkvG0wEACgkQYH1+F2Rqwn1YZgCfWAZgDPHatE3bHCSOzV17TjUX 8jEAn1uv7oxq+Qzp+0vb0SlUGJzoVHZn =9y1y -----END PGP SIGNATURE-----
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-- Best Regards, Xiao Lei
Many RDBMS pile up stale index structures to a certain extent and therefore have a cleanup operation ("vacuuming") which should be invoked regularly in order to maintain best performance. So it doesn't seem unreasonable if MonetDB also piles up some data related to already deleted rows. As I did not find anything related in the documentation, I wonder: 1. Does this actually apply to the MonetDB design? 2. If yes, is there a defined operation to do so (other than restarting the server, which might do the trick according to some obzervations). 3. When such a cleanup operation is performed (either through an on-line feature, or through server restart), are there any tradeoffs to be considered, like degradation of still useful indexes? Many thanks in advance. Best regards, Isidor original message follows:
Hi,
Does anyone has the same memory management problem as me?
When I inserted many records like: Insert into tbl1 (id,dt) values(1,blob ‘…………………………………………’); Memory is used up to 1G.
That's OK. But when I delete the whole table like: Delete from tbl1; None memory is released, still 1G is used.
And when i insert again, memory used keeps increasing.
Is this a problem or is it the way MonetDB works?
Thx.
-- Best Regards, Xiao Lei
participants (3)
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Isidor Zeuner
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Stefan de Konink
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Xiao Lei