Jinyu Zhang wrote: > > BRIN Scan: Optimize memory allocation in function 'bringetbitmap'. > We can allocate memory for some pointer before do long loop instead of > allocating > memory in long loop. > > Before optimizing code (warm run) > postgres=# select count(*) from lineitem where l_orderkey=1; > Time: 456.219 ms > > After optimizing code (warm run) > postgres=# select count(*) from lineitem where l_orderkey=1; > Time: 349.219 ms
Hmm, did you measure this in a c-assert-enabled build? Those are slower in allocation because of the memory-clobber thingy; without that, the allocations would be a lot faster, so perhaps the gains are not so interesting. Still, it's a lot of palloc/pfree calls that do not happen with your patch, so perhaps it's still worthwhile, but please do measure it. However I wonder if it would be simpler to have the dtup structure have the pointers, so that you can pass it as NULL in the first call and then followup calls reuse the one allocated in the first call. That makes the callers a bit less ugly, I think. -- Álvaro Herrera http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
