Re: Free space management within heap page - Mailing list pgsql-hackers

From Pavan Deolasee
Subject Re: Free space management within heap page
Date
Msg-id 2e78013d0701230543k54087265tce71bf74155dc8b1@mail.gmail.com
Whole thread Raw
In response to Re: Free space management within heap page  (Heikki Linnakangas <heikki@enterprisedb.com>)
List pgsql-hackers

On 1/23/07, Heikki Linnakangas <heikki@enterprisedb.com> wrote:
ITAGAKI Takahiro wrote:
> BLCKSZ is typically 8192 bytes and sizeof(ItemPointerData) is 4 bytes.
> 1/4 comes from 8192 / 4 = 2048. If we allow zero-size tuples, the line
> pointers area can bloat up to the ratio. We have tuples no less than
> 32 bytes-size, so the area is restricted 256 bytes now.

sizeof(ItemPointerData) == 6 bytes


I guess ITAGAKI meant sizeof(ItemIdData) which is 4 bytes. Thats the data type
for the line pointer.

Thanks,
Pavan

EnterpriseDB     http://www.enterprisedb.com

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