On Mon, Sep 11, 2017 at 5:40 PM, Amit Langote <langote_amit...@lab.ntt.co.jp> wrote: > On 2017/09/10 15:22, Michael Paquier 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, 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. > > Sorry, I didn't have time today to carefully go through the recent > discussion on this thread (starting with Tom's email wherein he said he > set the status of the patch to Waiting on Author). I will try tomorrow.
Thanks for the update! Once you get to this point, please let me know if you would like to work on a more complete patch for brin, gin and spgist. If you don't have enough room, I am fine to produce something. -- Michael -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
