Re: 8.3 / 8.2.6 restore comparison - Mailing list pgsql-hackers

From Joshua D. Drake
Subject Re: 8.3 / 8.2.6 restore comparison
Date
Msg-id 47C1B5F8.9090708@commandprompt.com
Whole thread Raw
In response to Re: 8.3 / 8.2.6 restore comparison  (Andrew Dunstan <andrew@dunslane.net>)
List pgsql-hackers
Andrew Dunstan wrote:
> 
> 
> Joshua D. Drake wrote:
>> Heikki Linnakangas wrote:
>>>
>>> We read 64 KB at a time, and then CopyReadLineText returns one line 
>>> at a time from that buffer.
>>
>> O.k. I am sure I am oversimplifying things but why are we returning 
>> one line at a time? That reads expensive to me. Just following the 
>> general, don't do inserts one at a time, do them in batch idea for 
>> example.
> 
> Quite simply because one line corresponds to one record. And yes, I 
> believe you are oversimplifying, or under several misapprehensions about 
> what can be done at this level.

Well I find without questioning, I won't get the answers so :).
 > It would be simple enough to change. Try it and see if it actually 
makes
> a difference. All you have to change is the define of RAW_BUF_SIZE.
> 

Fair enough. May I assume this is the only place I need to change it?

http://doxygen.postgresql.org/backend_2commands_2copy_8c-source.html#l00158


>> It looks like CopyReadAttributesText is used as part of the column 
>> breakup. It also appears that this happens "before" insert right? So 
>> if that is the case we are going to pay an additional penalty on the 
>> data checking.
>>
> 
> What? I don't understand what you are talking about.

Data checking on insert to the DB itself. I have no doubt that I may be 
wrong on this.

Joshua D. Drake



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