On Fri, Oct 25, 2019 at 9:19 PM Masahiko Sawada <sawada.m...@gmail.com> wrote: > > On Fri, Oct 25, 2019 at 2:06 PM Dilip Kumar <dilipbal...@gmail.com> wrote: > > > > On Fri, Oct 25, 2019 at 10:22 AM Masahiko Sawada <sawada.m...@gmail.com> > > wrote: > > > > > > For more detail of my idea it is that the first worker who entered to > > > vacuum_delay_point adds its local value to shared value and reset the > > > local value to 0. And then the worker sleeps if it exceeds > > > VacuumCostLimit but before sleeping it can subtract VacuumCostLimit > > > from the shared value. Since vacuum_delay_point are typically called > > > per page processed I expect there will not such problem. Thoughts? > > > > Oh right, I assumed that when the local balance is exceeding the > > VacuumCostLimit that time you are adding it to the shared value but > > you are adding it to to shared value every time in vacuum_delay_point. > > So I think your idea is correct. > > I've attached the updated patch set. > > First three patches add new variables and a callback to index AM. > > Next two patches are the main part to support parallel vacuum. I've > incorporated all review comments I got so far. The memory layout of > variable-length index statistics might be complex a bit. It's similar > to the format of heap tuple header, having a null bitmap. And both the > size of index statistics and actual data for each indexes follows. > > Last patch is a PoC patch that implements the shared vacuum cost > balance. For now it's separated but after testing both approaches it > will be merged to 0004 patch. I'll test both next week. > > This patch set can be applied on top of the patch[1] that improves > gist index bulk-deletion. So canparallelvacuum of gist index is true. >
+ /* Get the space for IndexBulkDeleteResult */ + bulkdelete_res = GetIndexBulkDeleteResult(shared_indstats); + + /* + * Update the pointer to the corresponding bulk-deletion result + * if someone has already updated it. + */ + if (shared_indstats->updated && stats[idx] == NULL) + stats[idx] = bulkdelete_res; + I have a doubt in this hunk, I do not understand when this condition will be hit? Because whenever we are setting shared_indstats->updated to true at the same time we are setting stats[idx] to shared stat. So I am not sure in what case the shared_indstats->updated will be true but stats[idx] is still pointing to NULL? -- Regards, Dilip Kumar EnterpriseDB: http://www.enterprisedb.com
