On Sun, Sep 10, 2017 at 11:52 AM, Michael Paquier <michael.paqu...@gmail.com> wrote: > On Sun, Sep 10, 2017 at 3:15 PM, Amit Kapila <amit.kapil...@gmail.com> wrote: >> On Sat, Sep 9, 2017 at 9:00 PM, Tom Lane <t...@sss.pgh.pa.us> wrote: >>> Michael Paquier <michael.paqu...@gmail.com> writes: >>>> On Fri, Sep 8, 2017 at 5:24 AM, Tom Lane <t...@sss.pgh.pa.us> wrote: >>>>> In short, this patch needs a significant rewrite, and more analysis than >>>>> you've done so far on whether there's actually any benefit to be gained. >>>>> It might not be worth messing with. >>> >>>> I did some measurements of the compressibility of the GIN meta page, >>>> looking at its FPWs with and without wal_compression and you are >>>> right: there is no direct compressibility effect when setting pd_lower >>>> on the meta page. However, it seems to me that there is an argument >>>> still pleading on favor of this patch for wal_consistency_checking. >>> >>> I think that would be true if we did both my point 1 and 2, so that >>> the wal replay functions could trust pd_lower to be sane in all cases. >>> But really, if you have to touch all the places that write these >>> metapages, you might as well mark them REGBUF_STANDARD while at it. >>> >>>> The same comment ought to be mentioned for btree. >>> >>> Yeah, I was wondering if we ought not clean up btree/hash while at it. >>> At the very least, their existing comments saying that it's inessential >>> to set pd_lower could use some more detail about why or why not. >>> >> >> +1. I think we can even use REGBUF_STANDARD in the hash for metapage >> where currently it is not used. I can give a try to write a patch for >> hash/btree part if you want. > > Coordinating efforts here would be nice. If you, Amit K, are taking > care of a patch for btree and hash >
I think here we should first agree on what we want to do. Based on Tom's comment, I was thinking of changing comments in btree/hash part and additionally for hash indexes, I can see if we can pass REGBUF_STANDARD for all usages of metapage. I am not sure if we want similar exercise for btree as well. -- 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