čt 6. 12. 2018 v 8:08 odesílatel Amit Kapila <amit.kapil...@gmail.com> napsal:
> On Thu, Dec 6, 2018 at 12:30 PM Pavel Stehule <pavel.steh...@gmail.com> > wrote: > > > > čt 6. 12. 2018 v 7:55 odesílatel Mithun Cy <mithun...@enterprisedb.com> > napsal: > >> > >> On Thu, Dec 6, 2018 at 11:13 AM Amit Kapila <amit.kapil...@gmail.com> > wrote: > >> > > >> > On Thu, Dec 6, 2018 at 10:03 AM Pavel Stehule < > pavel.steh...@gmail.com> wrote: > >> > > > >> > > čt 6. 12. 2018 v 5:02 odesílatel Mithun Cy < > mithun...@enterprisedb.com> napsal: > >> > >> > >> > >> COPY command seems to have improved very slightly with zheap in > both with size of wal and execution time. I also did some tests with insert > statement where I could see some regression in zheap when compared to heap > with respect to execution time. With further more investigation I will > reply here. > >> > >> > >> > > > >> > > 20% of size reduction looks like effect of fill factor. > >> > > > >> > > >> > I think it is because of smaller zheap tuple sizes. Mithun can tell > >> > more about setup whether he has used different fillfactor or anything > >> > else which could lead to such a big difference. > >> > >> Yes default fillfactor is unaltered, zheap tuples sizes are less and > >> alinged each at 2 Bytes > >> > > > > I am sorry, I know zero about zheap - does zheap use fill factor? if > yes, why? > > > > Good question. It is required because tuples can expand (Update tuple > to bigger length). In such cases, we try to perform in-place update > if there is a space in the page. So, having fillfactor can help. > > Thank you for reply :) Pavel -- > With Regards, > Amit Kapila. > EnterpriseDB: http://www.enterprisedb.com >
