On Fri, Sep 11, 2015 at 10:31 AM, Amit Kapila <amit.kapil...@gmail.com> wrote: > > Could you perhaps try to create a testcase where xids are accessed that > > are so far apart on average that they're unlikely to be in memory? And > > then test that across a number of client counts? > > > > Now about the test, create a table with large number of rows (say 11617457, > I have tried to create larger, but it was taking too much time (more than a > day)) > and have each row with different transaction id. Now each transaction should > update rows that are at least 1048576 (number of transactions whose status can > be held in 32 CLog buffers) distance apart, that way ideally for each update > it will > try to access Clog page that is not in-memory, however as the value to update > is getting selected randomly and that leads to every 100th access as disk > access.
What about just running a regular pgbench test, but hacking the XID-assignment code so that we increment the XID counter by 100 each time instead of 1? -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
