Re: [BUG] postgresql replaying WAL slowly when master drop a largenumber of relations in one transaction

On Wed, May 30, 2018 at 10:38:01AM +0800, 158306855 wrote:
> 3 But, the problem drop relation buffers by function
> DropRelFileNodesAllBuffers, that call by smgrdounlink. Each relation
> search the entire shared_buffer. This is unnecessary and can be
> optimized.

Yes, this is a known problem.  Fujii Masao has written a patch which
will likely get committed in v12.  Please see this thread:
https://www.postgresql.org/message-id/CAHGQGwHVQkdfDqtvGVkty+19cQakAydXn1etGND3X0PHbZ3+6w@mail.gmail.com
--
Michael