Re: [PROPOSAL] VACUUM Progress Checker.

On 2015/11/21 14:38, Jim Nasby wrote:
> On 11/19/15 7:29 PM, Amit Langote wrote:
>>> Another option is to provide the means for the index scan routines to
>>> >report their progress. Maybe every index AM won't use it, but it'd
>>> >certainly be a lot better than staring at a long_running boolean.
>> The boolean would be a workaround for sure. I'm also slightly tempted by
>> the idea of instrumenting vacuum scans of individual index AM's bulkdelete
>> methods. One precedent is how vacuum_delay_point() are sprinkled around in
>> the code. Another problem to solve would be to figure out how to pass
>> progress parameters around - via some struct or could they be globals just
>> like VacuumCost* variables are...
>
> It just occurred to me that we could do the instrumentation in
> lazy_tid_reaped(). It might seem bad to do in increment for every tuple in
> an index, but we're already doing a bsearch over the dead tuple list.
> Presumably that's going to be a lot more expensive than an increment
> operation.

Just to clarify, does this mean we report index vacuum progress in terms
of index items processed (not pages)? If so, how do we get total number of
index items to process (presumably across all indexes) for a given phase 2
round? As a context, we'd report phase 1 progress in terms of heap pages
processed of total heap pages.

Thanks,
Amit