Re: [gnome-db] libgda-v4 performance problems

["Vivien Malerba" <vmalerba gmail com>]

On Tue, Apr 8, 2008 at 9:17 PM, Massimo Cora' <maxcvs email it> wrote:
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>  Hi Vivien,
>
>
>  Vivien Malerba wrote:
>  > 2008/4/7 Johannes Schmid <jhs jsschmid de>:
>  >
>
> > I've just had a quich look at the code, and here is what I can think of:
>  > * avoid creating a GdaSet for the parameters everytime
>  > sdb_engine_add_new_file() is called (reuse the same one once created),
>  > you can also keep references to the individual GdaHolder objects
>  > within the GdaSet if you want. You can also create a unique GdaSet
>  > object which contains all the parameters for all the statements you
>  > have in the plugin, and use it everytime (only set the values which
>  > need to be set), have a look at the bottom of create_table_object() in
>  > gda-meta-store.c
>
>
>  well, simple but good idea! Yes making it global may avoid to create and
>  destroy everytime the GdaSet for every statement.
>  I would probably prefer taking a GdaSet reference for every statement
>  parsed, so there won't be the problem of lookup GdaHolders (if I
>  understood correctly GdaSet uses a GSList internally): in case of many
>  parameters, as in our example, it would need to iterate with a bad
>  performance.

I thouht a list would be good enough, but if you want I can send you a
patch which replaces the list with a hash table, so you can tell me if
it makes a difference and if it's worth keeping the modif.

>
>
>  > * you can use gda_holder_take_value() instead of
>  > gda_holder_set_value() followed by gda_value_free().
>
>  I'll have a look at this too
>
>
>  > * putting all the queries within one single transaction is usually
>  > _much_ faster with SQLite (maybe more than 10 times faster)
>  >
>
>  do you mean that we should avoid the transactions? I thought it was
>  faster, at least with others db it is...

No, I meant: use a BEGIN before the first INSERT and do a COMMIT after
the last INSERT, it should improve performances.

Cheers!