Re: Vacuum statistics

On 28.10.2024 16:40, Alexander Korotkov wrote:
> On Sun, Aug 25, 2024 at 6:59 PM Alena Rybakina
> <a.rybakina@postgrespro.ru>  wrote:
>> I didn't understand correctly - did you mean that we don't need SRF if
>> we need to display statistics for a specific object?
>>
>> Otherwise, we need this when we display information on all database
>> objects (tables or indexes):
>>
>> while ((entry = ScanStatSnapshot(pgStatLocal.snapshot.stats, &hashiter))
>> != NULL)
>> {
>>       CHECK_FOR_INTERRUPTS();
>>
>>       tabentry = (PgStat_StatTabEntry *) entry->data;
>>
>>       if (tabentry != NULL && tabentry->vacuum_ext.type == type)
>>           tuplestore_put_for_relation(relid, rsinfo, tabentry);
>> }
>>
>> I know we can construct a HeapTuple object containing a TupleDesc,
>> values, and nulls for a particular object, but I'm not sure we can
>> augment it while looping through multiple objects.
>>
>> /* Initialise attributes information in the tuple descriptor */
>>
>>    tupdesc = CreateTemplateTupleDesc(PG_STAT_GET_SUBSCRIPTION_STATS_COLS);
>>
>> ...
>>
>> PG_RETURN_DATUM(HeapTupleGetDatum(heap_form_tuple(tupdesc, values, nulls)));
>>
>>
>> If I missed something or misunderstood, can you explain in more detail?
> Actually, I mean why do we need a possibility to return statistics for
> all tables/indexes in one function call?  User anyway is supposed to
> use pg_stat_vacuum_indexes/pg_stat_vacuum_tables view, which do
> function calls one per relation.  I suppose we can get rid of
> possibility to get all the objects in one function call and just
> return a tuple from the functions like other pgstatfuncs.c functions
> do.
>
I haven’t thought about this before and agree with you. Thanks for the 
clarification! I'll fix the patch this evening and release the updated 
version.

-- 
Regards,
Alena Rybakina
Postgres Professional