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/ <http://www.2ndquadrant.com/> PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
