On Thu, Jul 30, 2020 at 09:21:23AM -0700, Jeff Davis wrote:
On Wed, 2020-07-29 at 17:32 -0700, Peter Geoghegan wrote:
How did you test this? What kind of difference are we talking about?
Essentially:
initHyperLogLog(&hll, 5)
for i in 0 .. one billion
addHyperLogLog(&hll, hash(i))
estimateHyperLogLog
The numbers are the same regardless of bwidth.
Before my patch, it takes about 15.6s. After my patch, it takes about
6.6s, so it's more than a 2X speedup (including the hash calculation).
Wow. That's a huge improvements.
How does the whole test (data + query) look like? Is it particularly
rare / special case, or something reasonable to expect in practice?
regards
--
Tomas Vondra http://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
