On Thu, Sep 15, 2016 at 7:13 AM, Robert Haas <robertmh...@gmail.com> wrote:
> On Thu, Sep 15, 2016 at 1:41 AM, Amit Kapila <amit.kapil...@gmail.com> > wrote: > > I think it is possible without breaking pg_upgrade, if we match all > > items of a page at once (and save them as local copy), rather than > > matching item-by-item as we do now. We are already doing similar for > > btree, refer explanation of BTScanPosItem and BTScanPosData in > > nbtree.h. > > If ever we want to sort hash buckets by TID, it would be best to do > that in v10 since we're presumably going to be recommending a REINDEX > anyway. We are? I thought we were trying to preserve on-disk compatibility so that we didn't have to rebuild the indexes. Is the concern that lack of WAL logging has generated some subtle unrecognized on disk corruption? If I were using hash indexes on a production system and I experienced a crash, I would surely reindex immediately after the crash, not wait until the next pg_upgrade. > But is that a good thing to do? That's a little harder to > say. > How could we go about deciding that? Do you think anything short of coding it up and seeing how it works would suffice? I agree that if we want to do it, v10 is the time. But we have about 6 months yet on that. Cheers, Jeff
