Re: COPY FREEZE and setting PD_ALL_VISIBLE/visibility map bits

Hi,

On 2019-04-03 10:19:17 +0530, Pavan Deolasee wrote:
> diff --git a/src/backend/commands/copy.c b/src/backend/commands/copy.c
> index c1fd7b78ce..09df70a3ac 100644
> --- a/src/backend/commands/copy.c
> +++ b/src/backend/commands/copy.c
> @@ -2833,6 +2833,15 @@ CopyFrom(CopyState cstate)
> !has_instead_insert_row_trig &&
> resultRelInfo->ri_FdwRoutine == NULL;
>
> + /*
> + * Note: As of PG12, COPY FREEZE is not supported on
> + * partitioned table. Nevertheless have this check in place so
> + * that we do the right thing if it ever gets supported.
> + */
> + if (ti_options & TABLE_INSERT_FROZEN)
> + CheckAndSetAllVisibleBulkInsertState(resultRelInfo->ri_RelationDesc,
> + bistate);
> +
> /*
> * We'd better make the bulk insert mechanism gets a new
> * buffer when the partition being inserted into changes.
> @@ -3062,6 +3071,15 @@ CopyFrom(CopyState cstate)
> firstBufferedLineNo);
> }
>
> + /*
> + * If we are inserting frozen tuples, check if the last page used can also
> + * be marked as all-visible and all-frozen. This ensures that a table can
> + * be fully frozen when the data is loaded.
> + */
> + if (ti_options & TABLE_INSERT_FROZEN)
> + CheckAndSetAllVisibleBulkInsertState(resultRelInfo->ri_RelationDesc,
> + bistate);
> +
> /* Done, clean up */
> error_context_stack = errcallback.previous;

I'm totally not OK with this from a layering
POV. CheckAndSetAllVisibleBulkInsertState is entirely heap specific
(without being named such), whereas all the heap specific bits are
getting moved below tableam.

Greetings,

Andres Freund