On Tue, Jan 3, 2017 at 6:41 PM, Simon Riggs <si...@2ndquadrant.com> wrote: > On 2 January 2017 at 21:23, Jim Nasby <jim.na...@bluetreble.com> wrote: > >> It's not clear from the thread that there is consensus that this feature is >> desired. In particular, the performance aspects of changing segment size >> from a C constant to a variable are in question. Someone with access to >> large hardware should test that. Andres[1] and Robert[2] did suggest that >> the option could be changed to a bitshift, which IMHO would also solve some >> sanity-checking issues. > > Overall, Robert has made a good case. The only discussion now is about > the knock-on effects it causes. > > One concern that has only barely been discussed is the effect of > zero-ing new WAL files. That is a linear effect and will adversely > effect performance as WAL segment size increases. >
Sorry, but I am not able to understand why this is a problem? The bigger the size of WAL segment, lesser the number of files. So IIUC, then it can only impact if zero-ing two 16MB files is cheaper than zero-ing one 32MB file. Is that your theory or you have something else in mind? -- With Regards, Amit Kapila. EnterpriseDB: http://www.enterprisedb.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
