Re: DBD::Pg, DBD::Oracle and others are slow with threads due to DBIS

On 14/03/12 10:37, Tim Bunce wrote:
> On Wed, Mar 14, 2012 at 08:52:38AM +0000, Martin J. Evans wrote:
>> On 13/03/12 21:44, Tim Bunce wrote:
>>> On Fri, Mar 02, 2012 at 03:11:17PM +0000, Tim Bunce wrote:
>>>>>
>>>>> The second patch, which makes DBIS more efficient, is a lot more complex,
>>>>> and more likely to break things (especially as it's changing a bunch of
>>>>> macros that are directly #included by the DBD drivers. You may need to
>>>>> bump API version numbers; I don't understand that bit.
>>>>
>>>> I'm concerned that changing the API, and thus forcing all compiled
>>>> drivers to be recompiled at the same time the DBI is installed,
>>>> isn't worth the gain. Especially as drivers shouldn't be using DBIS in
>>>> any hot code anyway.
>>
>> On the other hand, I want whatever speed I can get so I am happy to
>> recompile any DBDs to get it. Do people like me have to do without
>> improvements for the sake of those who don't want to recompile their
>> DBDs or can it be done in some other way or opt in.
>
> Per my recent message, implicit usage of DBIS is higher than I'd thought.
> The DBI will certain get Dave's improvements in some form, and yes,
> drivers will need to be recompiled. In fact they may *have* to be
> recompiled.
>
>> I don't think DBD::ODBC uses any DBIS stuff
>
> I had a (very) quick look and it loosk good. It's even using DBIc_TRACE() :)

I thought I was pretty up to date.

> There are cases where an imp_sth is passed as a parameter yet
> D_imp_xxh(sth) is being called. So you end up with imp_sth and imp_xxh
> pointers that point to the same thing. See dbd_st_fetch and dbd_bind_ph for
> example.  Just delete the D_imp_xxh(sth); line and change all imp_xxh in
> the function to be imp_sth instead. There may be cases where the same
> applies with imp_dbh.

Yeah, thanks, I'll fix those.
  
> There are other places where internal functions use the D_imp_xxh(h)
> initializer but that could be avoided by passing in imp_xxh from the
> caller. (And by *_xxh I mean _dbh, _sth - whichever is appropriate.)

I'll do that too.
  
>> but to be sure I'd echo
>> Merijn's reply; if you could point out what to look for and an
>> approach I'd happily change any DBD I could run and provide patches
>> for it (currently I have ODBC, Pg, Oracle, CSV, SQLite, mysql and all
>> those you get with DBI).
>
> Let me know if my reply to Merijn wasn't clear or complete enough.

It was fine.
  
I'll try and find time to sort Oracle out unless Yanick steps in.
I also meant to change Oracle to use DBD trace flag etc which gets rid of loads of ora_verbose code all over the place but I've not had time as yet as the level or rts reported for Oracle keeps me pretty busy.

Martin
-- 
Martin J. Evans
Easysoft Limited
http://www.easysoft.com