Re: [ROOT] TSQLServer... "-q" please?

From: Fons Rademakers (Fons.Rademakers@cern.ch)
Date: Thu Jul 10 2003 - 11:56:23 MEST


Hi John,

  I'll look into it. We could add an option to Query() that will tell
the DB systems to return row-by-row. I'll investigate.

Cheers, Fons.


On Wed, 2003-07-09 at 23:34, Dr. John Krane wrote:
> Hi,
> 
> I just spent the day adding a 30GB swap area (!) to my machine so I 
> could query my server with TSQLServer without crashing.  Unfortunately, 
> I just crashed again with an out-of-memory error.
> 
> Per Fons, the code collects the data in RAM and swap and then you use 
> TSQLRow (I think that's the class) to get row by row.  A db connection 
> in MySQL would looks like:
> 
> mysql -h myhostname -u myusername -p
> 
> If I put a "-q" in front of the "-h", then the db would give me 
> row-by-row as it found them instead of building up the huge (HUGE!) 
> buffer first and giving me the rows second.  Unfortunately, in root you 
> are stuck with
> 
> TSQLServer("myhostname", "myusername", "mypassword")
> 
> ...with no place for the -q option and no code in the class to do 
> anything with it.  May I please request the author revisit the 
> TSQLServer class to perhaps allow "-q" or some form of block transfers 
> ...I am stuffing swap to the bursting...and beyond.
> 
> (Although in MySQL it is possible to "limit 100000" or something to get 
> the first N events, it is not to my knowledge possible to skip those 
> same events when you come back for the remainder.  So I don't really 
> have much of a way around this.)
> 
> 	- John
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Org:    CERN, European Laboratory for Particle Physics.
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