On Thu, Oct 24, 2019 at 8:12 PM Masahiko Sawada <sawada.m...@gmail.com> wrote: > > On Thu, Oct 24, 2019 at 3:21 PM Dilip Kumar <dilipbal...@gmail.com> wrote: > > > > I have come up with the POC for approach (a). > > > > The idea is > > 1) Before launching the worker divide the current VacuumCostBalance > > among workers so that workers start accumulating the balance from that > > point. > > 2) Also, divide the VacuumCostLimit among the workers. > > 3) Once the worker are done with the index vacuum, send back the > > remaining balance with the leader. > > 4) The leader will sum all the balances and add that to its current > > VacuumCostBalance. And start accumulating its balance from this > > point. > > > > I was trying to test how is the behaviour of the vacuum I/O limit, but > > I could not find an easy way to test that so I just put the tracepoint > > in the code and just checked that at what point we are giving the > > delay. > > I also printed the cost balance at various point to see that after how > > much I/O accumulation we are hitting the delay. Please feel free to > > suggest a better way to test this. > > > > I have printed these logs for parallel vacuum patch (v30) vs v(30) + > > patch for dividing i/o limit (attached with the mail) > > > > Note: Patch and the test results are attached. > > > > Thank you! > > For approach (a) the basic idea I've come up with is that we have a > shared balance value on DSM and each workers including the leader > process add its local balance value to it in vacuum_delay_point, and > then based on the shared value workers sleep. I'll submit that patch > with other updates. >
I think it would be better if we can prepare the I/O balance patches on top of main patch and evaluate both approaches. We can test both the approaches and integrate the one which turned out to be good. Note that, I will be away next week, so I won't be able to review your latest patch unless you are planning to post today or tomorrow. -- With Regards, Amit Kapila. EnterpriseDB: http://www.enterprisedb.com
