Re: pgstat_send_connstats() introduces unnecessary timestamp and UDP overhead

Hi,

On 2021-08-25 12:51:58 +0900, Michael Paquier wrote:
> I was looking at this WIP patch, and plugging in the connection
> statistics to the table-access statistics looks like the wrong
> abstraction to me. I find much cleaner the approach of HEAD to use a
> separate API to report this information, as of
> pgstat_send_connstats().

As I said before, this ship has long sailed:

typedef struct PgStat_MsgTabstat
{
PgStat_MsgHdr m_hdr;
Oid m_databaseid;
int m_nentries;
int m_xact_commit;
int m_xact_rollback;
PgStat_Counter m_block_read_time; /* times in microseconds */
PgStat_Counter m_block_write_time;
PgStat_TableEntry m_entry[PGSTAT_NUM_TABENTRIES];
} PgStat_MsgTabstat;

> As of the two problems discussed on this thread, aka the increased
> number of UDP packages and the extra timestamp computations, it seems
> to me that we had better combine the following ideas for HEAD and 14,
> for now:
> - Avoid the extra timestamp computation as proposed by Laurenz in [1]
> - Throttle the frequency where the connection stat packages are sent,
> as of [2].

I think in that case we'd have to do the bigger redesign and move "live"
connection stats to backend_status.c...

Greetings,

Andres Freund