Subject Re: [firebird-support] Largish update - system limits
Author Alexandre Benson Smith
Aage Johansen wrote:

>In the process of converting a varchar field (MERKNAD) to a blob
>(KOMMENTAR) I had created the new field and was ready to move the
>(non-empty) values:
> update PERSON
> where MERKNAD is not Null and MERKNAD <> ''
>It had worked nicely on another table (of about 1 mill records - about
>200.000 was changed, I think), this table (PERSON) has about 6.5 mill
>records, where about 1 mill were going to be changed.
>Well, after a short while access to databases on the server became next to
>impossible. I just let it run, but the next morning the server (Win2k)
>complained about "low on virtual memory" - I didn't check actual values. I
>guess I shouldn't be surprised... A server reboot was done. (I've later
>used a program to do the updates, committing every 1000 records)
>Now, how can I know the (approx.) limits of the system before doing such an
>operation (big update)?
>This is Fb/1.0.3 (I believe) running on Win2k/SP2 with 512MB RAM. The
>update was run from IB_SQL on a pc.
>Aage J.
Hi Aege,

I have read something on fb-devel, about a "problem" with blobs, the
memory that the blob uses are just release on disconnect, so your update
could bring your server to the knees because of it...

just a guess...

see you !


Alexandre Benson Smith
THOR Software e Comercial Ltda.
Santo Andre - Sao Paulo - Brazil