[Monetdb-developers] [PF] Question about timings
Hi, A student of mine is trying to speed up some queries and is puzzled about the timing-readings he gets, for example: Trans 19681.811 msec Shred 0.000 msec Query 16384.143 msec Print 81.180 msec Timer 55087.438 msec The total of the first four 19.7+0+16.4+0.08 is approximately 36.2 seconds. "Timer" gives 55.1 seconds. Where are the remaining 18.9 seconds going? By the way, what do these measures precisely indicate? "Query", for example, can be interpreted as query compilation or query execution. Maurice. -- ---------------------------------------------------------------------- Dr.Ir. M. van Keulen - Assistant Professor, Data Management Technology Univ. of Twente, Dept of EEMCS, POBox 217, 7500 AE Enschede, Netherlands Email: m.vankeulen@utwente.nl, Phone: +31 534893688, Fax: +31 534892927 Room: ZI 3039, WWW: http://www.cs.utwente.nl/~keulen
On Tue, Mar 25, 2008 at 09:12:44AM +0100, Keulen, M. van (Maurice) wrote:
Hi,
A student of mine is trying to speed up some queries and is puzzled about the timing-readings he gets, for example:
Trans 19681.811 msec: Query translation ("compilation") (server) Shred 0.000 msec: Document shredding & loading (server) Query 16384.143 msec: Query execution (server) Print 81.180 msec: Result serialization (server) Timer 55087.438 msec: Wallclock (client; all above + client-server communication)
The total of the first four 19.7+0+16.4+0.08 is approximately 36.2 seconds. "Timer" gives 55.1 seconds. Where are the remaining 18.9 seconds going?
(unless there is a bug somewhere:) "client-server communication" (cf., http://www.cwi.nl/htbin/ins1/publications?request=abstract&key=Ma:TR-CWI:07) Which version of MonetDB/XQuery are we talking about?
By the way, what do these measures precisely indicate? "Query", for example, can be interpreted as query compilation or query execution.
See above. Stefan
Maurice.
-- | Dr. Stefan Manegold | mailto:Stefan.Manegold@cwi.nl | | CWI, P.O.Box 94079 | http://www.cwi.nl/~manegold/ | | 1090 GB Amsterdam | Tel.: +31 (20) 592-4212 | | The Netherlands | Fax : +31 (20) 592-4312 |
Thanx Stefan! Version is MonetDB/XQyert Stable 0.22 (using default backend). So the remaining time would be "client/server communication"??? That is an awful lot. The query is a reporting query, i.e., the query has many aggregates calculating all kinds of statistics and then creates XHTML structures for the resulting tables. The resulting XHTML-data is not so large that it would eat up 18.9 seconds. Aren't there any other aspects that may be involved here? Maurice. Stefan Manegold wrote:
On Tue, Mar 25, 2008 at 09:12:44AM +0100, Keulen, M. van (Maurice) wrote:
Hi,
A student of mine is trying to speed up some queries and is puzzled about the timing-readings he gets, for example:
Trans 19681.811 msec: Query translation ("compilation") (server) Shred 0.000 msec: Document shredding & loading (server) Query 16384.143 msec: Query execution (server) Print 81.180 msec: Result serialization (server) Timer 55087.438 msec: Wallclock (client; all above + client-server communication)
The total of the first four 19.7+0+16.4+0.08 is approximately 36.2 seconds. "Timer" gives 55.1 seconds. Where are the remaining 18.9 seconds going?
(unless there is a bug somewhere:) "client-server communication" (cf., http://www.cwi.nl/htbin/ins1/publications?request=abstract&key=Ma:TR-CWI:07)
Which version of MonetDB/XQuery are we talking about?
By the way, what do these measures precisely indicate? "Query", for example, can be interpreted as query compilation or query execution.
See above.
Stefan
Maurice.
-- ---------------------------------------------------------------------- Dr.Ir. M. van Keulen - Assistant Professor, Data Management Technology Univ. of Twente, Dept of EEMCS, POBox 217, 7500 AE Enschede, Netherlands Email: m.vankeulen@utwente.nl, Phone: +31 534893688, Fax: +31 534892927 Room: ZI 3039, WWW: http://www.cs.utwente.nl/~keulen
Maurice, (since I'm abroad:) just do a `pf query.xq > query.mil` and look for "time_" to find what is measured on the server side. Likewise, check the code of mclient (MapiClient.mx in clients) to see what is measured on the client side. If either you query or its result (or both) are large, communication time can be quite high (MAPI is not the most efficient protocol for lots of data). Where does the result goto? Console or file? if console, try redirecting it to a file. Stefan On Tue, Mar 25, 2008 at 10:59:11AM +0100, Keulen, M. van (Maurice) wrote:
Thanx Stefan!
Version is MonetDB/XQyert Stable 0.22 (using default backend).
So the remaining time would be "client/server communication"??? That is an awful lot. The query is a reporting query, i.e., the query has many aggregates calculating all kinds of statistics and then creates XHTML structures for the resulting tables. The resulting XHTML-data is not so large that it would eat up 18.9 seconds. Aren't there any other aspects that may be involved here?
Maurice.
Stefan Manegold wrote:
On Tue, Mar 25, 2008 at 09:12:44AM +0100, Keulen, M. van (Maurice) wrote:
Hi,
A student of mine is trying to speed up some queries and is puzzled about the timing-readings he gets, for example:
Trans 19681.811 msec: Query translation ("compilation") (server) Shred 0.000 msec: Document shredding & loading (server) Query 16384.143 msec: Query execution (server) Print 81.180 msec: Result serialization (server) Timer 55087.438 msec: Wallclock (client; all above + client-server communication)
The total of the first four 19.7+0+16.4+0.08 is approximately 36.2 seconds. "Timer" gives 55.1 seconds. Where are the remaining 18.9 seconds going?
(unless there is a bug somewhere:) "client-server communication" (cf., http://www.cwi.nl/htbin/ins1/publications?request=abstract&key=Ma:TR-CWI:07)
Which version of MonetDB/XQuery are we talking about?
By the way, what do these measures precisely indicate? "Query", for example, can be interpreted as query compilation or query execution.
See above.
Stefan
Maurice.
-- ---------------------------------------------------------------------- Dr.Ir. M. van Keulen - Assistant Professor, Data Management Technology Univ. of Twente, Dept of EEMCS, POBox 217, 7500 AE Enschede, Netherlands Email: m.vankeulen@utwente.nl, Phone: +31 534893688, Fax: +31 534892927 Room: ZI 3039, WWW: http://www.cs.utwente.nl/~keulen
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-- | Dr. Stefan Manegold | mailto:Stefan.Manegold@cwi.nl | | CWI, P.O.Box 94079 | http://www.cwi.nl/~manegold/ | | 1090 GB Amsterdam | Tel.: +31 (20) 592-4212 | | The Netherlands | Fax : +31 (20) 592-4312 |
participants (2)
-
Keulen, M. van (Maurice) -
Stefan Manegold