Re: Patch: show xid and xmin in pg_stat_activity and pg_stat_replication

On 2014-02-21 13:40:59 +0100, Christian Kruse wrote:
> diff --git a/src/backend/utils/adt/pgstatfuncs.c b/src/backend/utils/adt/pgstatfuncs.c
> index a4f31cf..e65b079 100644
> --- a/src/backend/utils/adt/pgstatfuncs.c
> +++ b/src/backend/utils/adt/pgstatfuncs.c
> @@ -536,7 +536,7 @@ pg_stat_get_activity(PG_FUNCTION_ARGS)
>  
>          oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
>  
> -        tupdesc = CreateTemplateTupleDesc(14, false);
> +        tupdesc = CreateTemplateTupleDesc(16, false);
>          TupleDescInitEntry(tupdesc, (AttrNumber) 1, "datid",
>                             OIDOID, -1, 0);
>          TupleDescInitEntry(tupdesc, (AttrNumber) 2, "pid",
> @@ -565,6 +565,10 @@ pg_stat_get_activity(PG_FUNCTION_ARGS)
>                             TEXTOID, -1, 0);
>          TupleDescInitEntry(tupdesc, (AttrNumber) 14, "client_port",
>                             INT4OID, -1, 0);
> +        TupleDescInitEntry(tupdesc, (AttrNumber) 15, "backend_xid",
> +                           XIDOID, -1, 0);
> +        TupleDescInitEntry(tupdesc, (AttrNumber) 16, "backend_xmin",
> +                           XIDOID, -1, 0);
>  
>          funcctx->tuple_desc = BlessTupleDesc(tupdesc);
>  
> @@ -588,11 +592,11 @@ pg_stat_get_activity(PG_FUNCTION_ARGS)
>  
>              for (i = 1; i <= n; i++)
>              {
> -                PgBackendStatus *be = pgstat_fetch_stat_beentry(i);
> +                LocalPgBackendStatus *be = pgstat_fetch_stat_local_beentry(i);
>  
>                  if (be)
>                  {
> -                    if (be->st_procpid == pid)
> +                    if (be->backendStatus.st_procpid
>                  == pid)

If we're going this route - which I am ok with - I'd suggest for doing
something like:

> -                PgBackendStatus *be = pgstat_fetch_stat_beentry(i);
> +                LocalPgBackendStatus *lbe = pgstat_fetch_stat_local_beentry(i);
> +                PgBackendStatus *be = &lb->backendStatus;

There seems little point in making all those lines longer and the
accompanying diff noise if all it costs is a local variable.

Makes sense?

Greetings,

Andres Freund

-- Andres Freund                       http://www.2ndQuadrant.com/PostgreSQL Development, 24x7 Support, Training &
Services