Re: [HACKERS] ANALYZE command progress checker

On 2017/04/05 10:17, Masahiko Sawada wrote:
> On Wed, Apr 5, 2017 at 1:49 AM, Robert Haas <robertmhaas@gmail.com> wrote:
>> On Tue, Apr 4, 2017 at 4:57 AM, Amit Langote
>> <Langote_Amit_f8@lab.ntt.co.jp> wrote:
>>> Hmm, you're right.  It could be counted with a separate variable
>>> initialized to 0 and incremented every time we decide to add a row to the
>>> final set of sampled rows, although different implementations of
>>> AcquireSampleRowsFunc have different ways of deciding if a given row will
>>> be part of the final set of sampled rows.
>>>
>>> On the other hand, if we decide to count progress in terms of blocks as
>>> you suggested afraid, I'm afraid that FDWs won't be able to report the
>>> progress.
>>
>> I think it may be time to push this patch out to v11.  It was
>> submitted one day before the start of the last CommitFest, the design
>> wasn't really right, and it's not clear even now that we know what the
>> right design is.  And we're pretty much out of time.
>>
>
> +1
> We're encountering the design issue and it takes more time to find out
> right design including FDWs support.
>
> Regards,
>
> --
> Masahiko Sawada
> NIPPON TELEGRAPH AND TELEPHONE CORPORATION
> NTT Open Source Software Center

Hi Vinayak,

I found a typo in your patch: s/taht/that/

sampling.c   /* Report total number of blocks taht will be sampled */

Then, regarding FDWs support, I believe it means postgres_fdw support (is my understanding right?).
You might better to put pgstat_progress_update_param() into these functions, maybe.  postgres_fdw.c    -
postgresAnalyzeForeignTable   - postgresAcquireSampleRowsFunc
 

And PgFdwAnalyzeState has these variables, hopefully you can get current number of rows
as a progress indicator.
  sturuct PgFdwAnalyzeState  ...    /* collected sample rows */    HeapTuple  *rows;           /* array of size
targrows*/    int         targrows;       /* target # of sample rows */    int         numrows;        /* # of sample
rowscollected */
 
    /* for random sampling */    double      samplerows;     /* # of rows fetched */    double      rowstoskip;     /*
#of rows to skip before next sample */  ...
 

I hope it will help you.

Regards,
Tatsuro Yamada