On Wed, Jun 13, 2012 at 3:57 AM, Amit Kapila <amit.kap...@huawei.com> wrote: >> 1) Keep track # times the last transaction id was repeatedly seen in >> tqual.c (resetting as soon as a new xid was touched. We can do this >> just for xmin, or separately for both xmin and xmax. > > Will this be done when we see a new xid duricg scan of tuple, if yes then > Won't this logic impact incase there are very few records per transaction in > database. > As in that case the new optimization won't help much, but it adds the new > instructions.
Yes, but only in the unhinted case -- in oltp workloads tuples get hinted fairly quickly so I doubt this would be a huge impact. Hinted scans will work exactly as they do now. In the unhinted case for OLTP a few tests are added but that's noise compared to the other stuff going on. >> We can also try to be smart and disable >> the 'avoid setting the hint bit' logic if the page is already dirty. > > Whats the benefit for not setting hint bit for a already dirty page. Nothing -- we are disabling the '*avoid* setting the hint bit' logic (double negative there). In other words we would be disabling the setting of hint bits if we see the same transaction many times in a row, but only if the page isn't dirty. merlin -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
