performance problems on Delete

Hi alls,

we have a performance issue on deleting data from a table.

the delete is on the index key so should be very fast but the table
have 13 contraints of type foreign keys and the slowness seems due to
all the works done with the constraint.
Trying to drop the constraint and execute the delete the result is
immediate.

Is there a way to speed up this type of operations??

Any suggestion higly appreciated


Silvio

---






Utilizziamo i dati personali che la riguardano esclusivamente per nostre finalità amministrative e contabili, anche quando li comunichiamo a terzi. Informazioni dettagliate, anche in ordine al Suo diritto di accesso e agli altri Suoi diritti, sono riportate alla pagina http://www.savinodelbene.com/news/privacy.html
Se avete ricevuto questo messaggio per errore Vi preghiamo di ritornarlo al mittente eliminandolo assieme agli eventuali allegati, ai sensi art. 616 codice penale http://www.savinodelbene.com/codice_penale_616.html
L'Azienda non si assume alcuna responsabilità giuridica qualora pervengano da questo indirizzo messaggi estranei all'attività lavorativa o contrari a norme.
--

--
Sent via pgsql-admin mailing list (pgsql-admin@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-admin

Re: performance problems on Delete

Silvio Brandani wrote:

> we have a performance issue on deleting data from a table.
>
> the delete is on the index key so should be very fast but the table
> have 13 contraints of type foreign keys and the slowness seems due
> to all the works done with the constraint.
> Trying to drop the constraint and execute the delete the result is
> immediate.

The usual reason for this is that you don't have indexes on the
referencing columns, so to check whether the delete is OK it has to
scan the related tables. Think about what rows need to be checked to
determine whether the delete is allowed and index the columns which
will allow fast access to them.

-Kevin

--
Sent via pgsql-admin mailing list (pgsql-admin@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-admin

Re: performance problems on Delete

Kevin Grittner ha scritto:
> Silvio Brandani wrote:
>
>
>> we have a performance issue on deleting data from a table.
>>
>> the delete is on the index key so should be very fast but the table
>> have 13 contraints of type foreign keys and the slowness seems due
>> to all the works done with the constraint.
>> Trying to drop the constraint and execute the delete the result is
>> immediate.
>>
>
> The usual reason for this is that you don't have indexes on the
> referencing columns, so to check whether the delete is OK it has to
> scan the related tables. Think about what rows need to be checked to
> determine whether the delete is allowed and index the columns which
> will allow fast access to them.
>
> -Kevin
>
>
yes,
you where right , an index was missing.

thanks a lot

--

---






Utilizziamo i dati personali che la riguardano esclusivamente per nostre finalità amministrative e contabili, anche quando li comunichiamo a terzi. Informazioni dettagliate, anche in ordine al Suo diritto di accesso e agli altri Suoi diritti, sono riportate alla pagina http://www.savinodelbene.com/news/privacy.html
Se avete ricevuto questo messaggio per errore Vi preghiamo di ritornarlo al mittente eliminandolo assieme agli eventuali allegati, ai sensi art. 616 codice penale http://www.savinodelbene.com/codice_penale_616.html
L'Azienda non si assume alcuna responsabilità giuridica qualora pervengano da questo indirizzo messaggi estranei all'attività lavorativa o contrari a norme.
--

--
Sent via pgsql-admin mailing list (pgsql-admin@postgresql.org)
To make changes to your subscription:
http://www.postgresql.org/mailpref/pgsql-admin