Обсуждение: bug in pageinspect contrib modul

The following code is in btreefuncs.c function GetBTPageStatistics:

stat->max_avail = BLCKSZ - (BLCKSZ - phdr->pd_special + SizeOfPageHeaderData);

I think it should be:

stat->max_avail = BLCKSZ - (phdr->pd_special + SizeOfPageHeaderData);

        Zdenek


--
Zdenek Kotala              Sun Microsystems
Prague, Czech Republic     http://sun.com/postgresql

Zdenek Kotala wrote:
> The following code is in btreefuncs.c function GetBTPageStatistics:
>
> stat->max_avail = BLCKSZ - (BLCKSZ - phdr->pd_special +
> SizeOfPageHeaderData);
>
> I think it should be:
>
> stat->max_avail = BLCKSZ - (phdr->pd_special + SizeOfPageHeaderData);

Umm, I don't think so. pd_special is the offset to the start of the
special area, so (BLCKSZ - pd_special) is the size of the special area.

However, that max_avail field actually looks like dead code, anyway.

--
   Heikki Linnakangas
   EnterpriseDB   http://www.enterprisedb.com

Heikki Linnakangas napsal(a):
> Zdenek Kotala wrote:
>> The following code is in btreefuncs.c function GetBTPageStatistics:
>>
>> stat->max_avail = BLCKSZ - (BLCKSZ - phdr->pd_special +
>> SizeOfPageHeaderData);
>>
>> I think it should be:
>>
>> stat->max_avail = BLCKSZ - (phdr->pd_special + SizeOfPageHeaderData);
>
> Umm, I don't think so. pd_special is the offset to the start of the
> special area, so (BLCKSZ - pd_special) is the size of the special area.
>
> However, that max_avail field actually looks like dead code, anyway.

Yeah, you are right. I forgot that pd_special does not contain size but offset.

    Thanks Zdenek



--
Zdenek Kotala              Sun Microsystems
Prague, Czech Republic     http://sun.com/postgresql