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, would you, Amit L, write the part for GIN, BRIN and SpGist? This needs a careful lookup as many code paths need a lookup so it may take time. Please note that I don't mind double-checking this part if you don't have enough room to do so. -- Michael -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers