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From: Simon Riggs <[email protected]>
To: Tom Lane <[email protected]>
Cc: Neil Conway <[email protected]>
Cc: Hannu Krosing <[email protected]>
Cc: Josh Berkus <[email protected]>
Cc: [email protected]
Subject: Re: VLDB Features
Date: Sat, 15 Dec 2007 09:14:16 +0000
Message-ID: <[email protected]> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>
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On Fri, 2007-12-14 at 18:22 -0500, Tom Lane wrote:
> Neil Conway <[email protected]> writes:
> > By modifying COPY: COPY IGNORE ERRORS or some such would instruct COPY
> > to drop (and log) rows that contain malformed data. That is, rows with
> > too many or too few columns, rows that result in constraint violations,
> > and rows containing columns where the data type's input function raises
> > an error. The last case is the only thing that would be a bit tricky to
> > implement, I think: you could use PG_TRY() around the InputFunctionCall,
> > but I guess you'd need a subtransaction to ensure that you reset your
> > state correctly after catching an error.
> 
> Yeah.  It's the subtransaction per row that's daunting --- not only the
> cycles spent for that, but the ensuing limitation to 4G rows imported
> per COPY.

I'd suggest doing everything at block level
- wrap each new block of data in a subtransaction
- apply data to the table block by block (can still work with FSM). 
- apply indexes in bulk for each block, unique ones first. 

That then gives you a limit of more than 500 trillion rows, which should
be enough for anyone.

-- 
  Simon Riggs
  2ndQuadrant  http://www.2ndQuadrant.com

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