DaveGuest
How do I time queries? e.g.
select vwap:size wavg price by date from trade where sym =`RBS
Is there a query analyser? profiler?
You can use \t to record how long a query takes:
q)trade:`date xasc 100000?([] sym:1000?`RBS`o`i; size:1000?1000; price:1000?10.; date:1000?.z.d)
q)select vwap:size wavg price by date from trade where sym =`RBS
date | vwap
----------| ---------
2000.01.10| 6.852109
2000.01.18| 7.724738
2000.01.22| 7.328888
2000.01.30| 7.99496
2000.02.08| 0.8450724
2000.02.10| 0.276614
..
q)\t select vwap:size wavg price by date from trade where sym =`RBS
7
q)\t select vwap:size wavg price by date from trade where sym =`RBS
4
To get a reliable timing use a do loop to repeat the action a number of times:
q)\t do[100; select vwap:size wavg price by date from trade where sym =`RBS]
238
q)\t do[100; select vwap:size wavg price by date from trade where sym =`RBS]
225
\ts can be used to return both the time taken and the space used in bytes. Alternatively you can use the system format:
q)\ts do[100; select vwap:size wavg price by date from trade where sym =`RBS]
219 1772336
q)system "ts do[100; select vwap:size wavg price by date from trade where sym =`RBS]"
245 1772336
.
