binomiq

4 ms·

1. 1.▲
   by binomiq 6y ago

   In your benchmarks, KDB's max on longs takes twice as long as sum on longs. I am not able to replicate this with the most recent version of KDB (2020.03.30). $QHOME/l64/q -s 4 KDB+ 4.0 2020.03.30 Copyright (C) 1993-
2. 2.▲
   by binomiq 6y ago

   KDB works around this by storing the nanos in 64 bits but only for a particular time range. 1707.09.22D00:12:43.145224194 (max negative) to 2292.04.10D23:47:16.854775806 (max positive) With 0 at 2000.01.01D00:00:00.000000000
3. 3.▲
   by binomiq 6y ago

   Were these benchmarks before or after 2020.03.26? There was a bug that caused max operations to take twice as long. From the KDB+ 4.0 release notes: 2020.03.26 FIX fixed performance regression for max. e.g. q)x:100000000?100;system"ts