On Thu, Jan 25, 2018 at 12:14 AM, Fabrízio de Royes Mello <fabriziome...@gmail.com> wrote: > > > On Wed, Jan 24, 2018 at 12:31 PM, Fabrízio de Royes Mello > <fabriziome...@gmail.com> wrote: >> >> >> >> On Tue, Jan 23, 2018 at 11:44 PM, Masahiko Sawada <sawada.m...@gmail.com> >> wrote: >> > >> > On Tue, Jan 23, 2018 at 8:03 PM, Fabrízio de Royes Mello >> > <fabriziome...@gmail.com> wrote: >> > > >> > > Em ter, 23 de jan de 2018 às 03:36, Masahiko Sawada >> > > <sawada.m...@gmail.com> >> > > escreveu: >> > >> >> > >> Hi all, >> > >> >> > >> While reading the code, I realized that the requesting an autovacuum >> > >> work-item could fail in silence if work-item array is full. So the >> > >> users cannot realize that work-item is never performed. >> > >> AutoVacuumRequestWork() seems to behave so from the initial >> > >> implementation but is there any reason of such behavior? It seems to >> > >> me that it can be a problem even now that there is only one kind of >> > >> work-item. Attached patch for fixing it. >> > > >> > > >> > > Seems reasonable but maybe you can use the word "worker" instead of >> > > "work >> > > item" for report message. >> > > >> > >> > Thank you for the comment. >> > Or can we use the word "work-item" since the commit log and source >> > code use this word? >> > >> >> You're correct, I misunderstood it thinking about autovacuum workers and >> not the internal workitem array. >> >> As NUM_WORKITEMS is fixed in 256 we don't have any real feedback if in a >> real workload this can send a lot of messages to log, so: >> 1) maybe invent a new GUC to control if we need or not to send this info >> to log >> 2) change elevel for DEBUG1 >>
Hmm, I'd rather think to log the message at LOG level and to have a new GUC to control the size of maximum of work-items array . I think we should always notify users that work-item couldn't get added because it can become a potential performance problem. Also it might lead other problems once we have other types of work-item. In the log message, we can hint for user that you might want to increase maximum of work-items array. > > Looking better for the autovacuum code your patch will work just for BRIN > request "brin_summarize_range", correct? > Correct. Regards, -- Masahiko Sawada NIPPON TELEGRAPH AND TELEPHONE CORPORATION NTT Open Source Software Center