Re: Long Parse Time for a big Statement

Hello Lothar,
sorry, if I missed some already explained details in the reply chain.

1. Have you already sampled the parsing (let's say with 20 CPU samples per second for 2 or 3 minutes or so) and created a flame graph afterwards?
2. Are you sure that you are running out of memory in shared pool and not also in PGA? Parsing allocates memory in both areas depending on what is happening.

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> Lothar Flatz <l.flatz_at_bluewin.ch> hat am 17.01.2022 13:59 geschrieben:
>
> Hi,
>
> At one customer site we see generated statements, actually reports. The
> parsetime for such a statement is over an hour, if it finishes at all.
> It is possible we see "ORA-04031:" when we run out of memory in the
> shared pool.
> How big these statements are is hard to tell, since it depends on
> formatting. With sql developer formatting i get in one typical example >
> 130000 lines.
> The statements are constructed relatively simple.
> It seems to be a kind of change report where columns from different
> tables are retrieved.
> At the beginning is a big case statement where a meaningful name is
> generated for a value followed by this values. I counted 7400 case
> entries as per statement in one case.
> I addition we have a number of big inlists.
> All this is running against a union view of 55 Tables.
> In other words: If i want to stress the parser I would construct a
> statement exactly like this.
> However, one hour seems to be a unrealistically long parse time.
> Even though that statement needs to be rewritten, but this will take time.
> I want to know if there is any quick fix like increasing the shared pool
> a lot. (Which I can't test unfortunately any time soon due lack of memory).
> Any ideas how to speed up the parse time?
>
> Database version is 19.7. Shared Pool size is 20GB
>
> Thanks
>
> Lothar

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