Re: open/lseek overhead with many partitions (including with "fasterpartitioning pruning")

On 4 April 2018 at 07:46, Justin Pryzby <pryzby@telsasoft.com> wrote:
> TLDR: even with "faster pruning" patch, pg11dev open()+lseek() every file
> backing every table being queried, even for those partitions eventually
> "excluded".

Yeah, this will no doubt be due to the fact that we still build
RelOptInfos in the planner for all partitions, so we're still doing
get_relation_info() and estimate_rel_size() for each of those. It
might be possible to delay that call until we know we're going to need
the partition.  I imagine we wouldn't need to know the size of the
relation until after set_rel_sizes, but I've not checked.


-- 
 David Rowley                   http://www.2ndQuadrant.com/
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