> I see the problem, but I don't buy the argument that it wastes large amounts > of memory. Or do you have some evidence that it does? No. I don’t have any trouble caused by it. I think I did not mention it wastes 'large' amount of memory but 'a few'.
> I think we should fix it, but not backpatch. I agree that backpatch is unnecessary. I hope it will be fixed for the current development version at some suitable opportunity. Best regards, Takashi Horikawa NEC Corporation Knowledge Discovery Research Laboratories > -----Original Message----- > From: pgsql-hackers-ow...@postgresql.org > [mailto:pgsql-hackers-ow...@postgresql.org] On Behalf Of Simon Riggs > Sent: Friday, February 19, 2016 6:24 PM > To: Horikawa Takashi(堀川 隆) > Cc: PostgreSQL Hackers > Subject: Re: [HACKERS] Typo in bufmgr.c that result in waste of memory > > On 19 February 2016 at 02:58, Takashi Horikawa <t-horik...@aj.jp.nec.com> > wrote: > > > > I have just found a typo in the source code (not in a comment) of > bufmgr.c > that result in waste of memory. It might be a 'bug' but it does > not result > in any incorrect operation but just results in waste of a few memory > resource. > > As sizeof(PrivateRefCountArray) found in InitBufferPoolAccess() > is 64 and > sizeof(PrivateRefCountEntry) which should be used here is 8, this > typo > produces 56 byte of unused memory area per one PrivateRefCount entry > in the > hash table. I think this result in not only the waste of memory > but also > reduces the cache hit ratio. > > X hash_ctl.entrysize = sizeof(PrivateRefCountArray); > O hash_ctl.entrysize = sizeof(PrivateRefCountEntry); > > > > I see the problem, but I don't buy the argument that it wastes large amounts > of memory. Or do you have some evidence that it does? > > I think we should fix it, but not backpatch. > > -- > > Simon Riggs http://www.2ndQuadrant.com/ > PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
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