Yes, that's right. Commit_retaining doesn't release acquired resources and it shouldn't. But I still believe it's a bug in the Firebird itself, because procedure after creation should decrement relation use count, but it doesn't. Any of the steam blob tests fail even when executed separetely. Surely I would like to see the same optimization in Jaybird 3, but I'm currently more interested in 2.2.*.
On Sat, May 30, 2015 at 10:58 AM, Mark Rotteveel <m...@lawinegevaar.nl> wrote: > On 29-5-2015 16:10, Maxim Smyatkin wrote: > > Hello, > > Recently we've got an information from some company that they would like > > to use Firebird/Red Database with OpenCMS, but they couldn't afford it > > because of bad performance. We compared it with PostgreSQL and it was > > true - on some page views PG showed 4 seconds while for Firebird it was > > almost 27 seconds. Skimming through performance audit log explained us, > > that CMS executes lots (thousends) of small selects per page view. I > > agree that it seems like a horrible design, but anyway PG handled it > > much faster. > > The reasons were: > > 1. In auto-commit mode Jaybird wraps any statement into start/commit > > calls. So, it does two additional calls to DBMS per statement; > > 2. It doesn't really matter if the statement changes anything or not. It > > executes start/commit in both cases. > > Here is a pull request with changes to fix this behaviour using DBMS > > API's auto-commit flag: > > https://github.com/FirebirdSQL/jaybird/pull/1 > > Any further information about implementation or results is in comment to > > the pull request. > > > > It seems to work excellent with OpenCMS, but Jaybird's unit tests show > > several problems: > > > > 1. testBatch shows failure, because now every statement in the batch > > execution mode is commited separately. This behaviour is perfectly fine > > as JDBC specification states that you can't rely on batch mode + > > auto-commit mode. Maybe, Firebird has some clients who rely on this > > behaviour, I don't know. Anyway, you can wrap batch execution into > > freshly started non auto-commit transaction, if you wish. I decided to > > leave this decision up to you and didn't touch it. > > I am not sure if others depend on this behavior, but I'd prefer to keep > the behavior of this as it was. Your suggestion to wrap it in its own > transaction seems a good one, but it might be complex to implement (a > lot of Jaybird is built around a "single active transaction" model of > transactions. > > > 2. Whole TestFBBlobStream family (6 tests) fails. The reason is bug in > > Firebird transaction engine. When transaction started in auto-commit > > mode actually commits (via commit_retaining) it doesn't free any > > resources. E.g., what happens in these tests is: > > - we create a procedure P using a table T. > > - the P states its interest in the T (while looking for P's > dependencies); > > - transaction commits the changes with retaining flag and forgets to say > > that it isn't interested in the T anymore; > > - we try to drop the T, but we can't because it is marked as "in use"! > > I attached a patch (for 2.5 branch) to release resources on > > commit_retaining. But I believe the problem is rather in > > modify_procedure()'s code, because it should release rel_use_counts on > > its own. > > As far as I know the keeping resources like the cursor and blobs open on > commit_retaining is intentional (I believe it is one of the reasons for > the "retaining" in the name). The error itself is probably related to > the fact that some Jaybird tests unnecessarily cleanup after themselves. > > > 3. TestDriverConnectionPoolDataSource.testPreparedStatement fails with > > an Error. I don't know why it happens and how to fix it. Looks like some > > kind of race conditions, but I'm not sure. If anyone could look into it, > > it would be awesome. > > I'll look into it. I hadn't noticed before that you made the pull > request for Branch_2_2, I will first release Jaybird 2.2.8 (this > weekend) before looking at it. > > > > > Here is my commit for OpenCMS, so that it could effectively use modified > > Jaybird: > > > https://github.com/Smyatkin-Maxim/opencms-core/commit/4b1901f4d339c4ec710ad84d316e70f694068dc8 > > I will issue pull request as soon as I verify that this Jaybird > > improvement is fine. > > Mark > > -- > Mark Rotteveel > > > ------------------------------------------------------------------------------ > Firebird-Devel mailing list, web interface at > https://lists.sourceforge.net/lists/listinfo/firebird-devel > -- Thank you! Smyatkin Maxim, Red Soft Corporation. https://www.linkedin.com/in/smyatkin
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