Re: Changeset Extraction v7.7

On 2014-02-24 17:06:53 -0500, Robert Haas wrote:
> - heap_page_prune_opt(scan->rs_rd, buffer, RecentGlobalXmin);
> + if (IsSystemRelation(scan->rs_rd)
> + || RelationIsAccessibleInLogicalDecoding(scan->rs_rd))
> + heap_page_prune_opt(scan->rs_rd, buffer, RecentGlobalXmin);
> + else
> + heap_page_prune_opt(scan->rs_rd, buffer, RecentGlobalDataXmin);
>
> Instead of changing the callers of heap_page_prune_opt() in this way,
> I think it might be better to change heap_page_prune_opt() to take
> only the first two of its current three parameters; everybody's just
> passing RecentGlobalXmin right now anyway.

I've changed stuff this way, and it indeed looks better.

I am wondering about the related situation of GetOldestXmin()
callers. There's a fair bit of duplicated logic in the callers, before
but especially after this patchset. What about adding 'Relation rel'
parameter instead of `allDbs' and `systable'? That keeps the logic
centralized and there's been a fair amount of talk about vacuum
optimizations that could also use it.
It's a bit sad that that requires including rel.h from procarray.h...

What do you think? Isolated patch attached.

Greetings,

Andres Freund

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