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Re: extra rowcopy in ResultSet allways needed ?.

From: Kris Jurka <books(at)ejurka(dot)com>
To: Gustav Trede <gustav(dot)trede_wsdevel(at)telia(dot)com>
Cc: pgsql-jdbc(at)postgresql(dot)org
Subject: Re: extra rowcopy in ResultSet allways needed ?.
Date: 2008-02-16 17:02:12
Message-ID: 47B71714.2050202@ejurka.com (view raw or flat)
Thread:
Lists: pgsql-jdbc
Gustav Trede wrote:
> Kris Jurka skrev:
>> The rowBuffer copy is only needed for updateable ResultSets, so we 
>> could probably wrap all those calls with isUpdateable() { }.  Are you 
>> seein a significant performance impact from those calls or are you 
>> just curious?
>>
> 
> its good news that its avoidable.
> I buffer roughly 2Gbyte of data by jdbc in RAM.
> im using several threads to max the speed and im currently cpu bound for 
> performance.
> its importent for me to keep the init time as low as possible, since it 
> delays failover response in my setup.
> (long time outs on client IO keeps client in an ok state though.)
> 
> I have a general interests in performance despite that im using 
> webservices for clients =),
> and tend to look around in code on my sparetime, and i sometimes find 
> things.
> Whenever the things are not risky to implement, its often to be 
> considered free as in beer.
> Its only if there is noticable complexity, that the performance boost 
> must be proven to be very substantial inorder
> to motivate risky code changes imo.
> 
> I would be happy if its possible to check for isUpdatable in the 
> official codebase,
> its a mess for me to keep local patches synced with CVS.
> 
> I dont have any hard numbers atm.
> If its needed, i can try to provide it next week or so ?
> 

No I don't need the numbers, I was just curious if you had them handy. 
Also I was initially looking at the full cost of isUpdateable and the 
idea that for a small ResultSet it would be faster to just do the copy 
rather than doing the parsing and stuff to see if a ResultSet was 
updateable.  Re-reading that now, we don't really want to call 
isUpdateable, but probably just wrap things in "if (resultsetconcurrency 
== ResultSet.CONCUR_UPDATABLE) { } ".  That'll be a simple quick check 
that should always be a win.

So are you planning on coding this up, or just throwing it out as a 
suggestion?

Kris Jurka


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Subject: Re: extra rowcopy in ResultSet allways needed ?.
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