[MonetDB-users] nanosleep?
I am running a query, similar to this: SELECT distinct extract(day from time), extract (month from time) from T; The query takes a long time because the table T has over 280 Million records. However I was curious to run an strace on the mserver5 process and I notced "nanosleep". Is the process sleeping or waiting? strace -p 25984 Process 25984 attached - interrupt to quit restart_syscall(<... resuming interrupted call ...>) = 0 nanosleep({5, 0}, {5, 0}) = 0 nanosleep({5, 0}, {5, 0}) = 0 nanosleep({5, 0}, {5, 0}) = 0
On 10-05-2009 10:12:19 -0400, Mag Gam wrote:
I am running a query, similar to this:
SELECT distinct extract(day from time), extract (month from time) from T;
The query takes a long time because the table T has over 280 Million records. However I was curious to run an strace on the mserver5 process and I notced "nanosleep".
Is the process sleeping or waiting?
strace -p 25984 Process 25984 attached - interrupt to quit restart_syscall(<... resuming interrupted call ...>) = 0 nanosleep({5, 0}, {5, 0}) = 0 nanosleep({5, 0}, {5, 0}) = 0 nanosleep({5, 0}, {5, 0}) = 0
Those are various threads that just wait for a while before they look if they have to do something again.
Mag Gam wrote:
Is the process sleeping or waiting?
strace -p 25984 Process 25984 attached - interrupt to quit restart_syscall(<... resuming interrupted call ...>) = 0 nanosleep({5, 0}, {5, 0}) = 0 nanosleep({5, 0}, {5, 0}) = 0 nanosleep({5, 0}, {5, 0}) = 0
Using that syntax I think you miss the forks/threads :) So you might up at what is happening at the server console. But there is a tool that gives MUCH better insight in what MonetDB is actually doing: stethoscope. Stefan
I am running a query, similar to this:
SELECT distinct extract(day from time), extract (month from time) from T;
The query takes a long time because the table T has over 280 Million records. However I was curious to run an strace on the mserver5 process and I notced "nanosleep".
Is the process sleeping or waiting?
strace -p 25984 Process 25984 attached - interrupt to quit restart_syscall(<... resuming interrupted call ...>) = 0 nanosleep({5, 0}, {5, 0}) = 0 nanosleep({5, 0}, {5, 0}) = 0 nanosleep({5, 0}, {5, 0}) = 0
Mag Gam wrote: there are multiple processes running, including one to manage your memory, which is not always running
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Thankyou very much for the quick and detailed responses! On Sun, May 10, 2009 at 10:24 AM, Martin Kersten <Martin.Kersten@cwi.nl> wrote:
I am running a query, similar to this:
SELECT distinct extract(day from time), extract (month from time) from T;
The query takes a long time because the table T has over 280 Million records. However I was curious to run an strace on the mserver5 process and I notced "nanosleep".
Is the process sleeping or waiting?
strace -p 25984 Process 25984 attached - interrupt to quit restart_syscall(<... resuming interrupted call ...>) = 0 nanosleep({5, 0}, {5, 0}) = 0 nanosleep({5, 0}, {5, 0}) = 0 nanosleep({5, 0}, {5, 0}) = 0
Mag Gam wrote: there are multiple processes running, including one to manage your memory, which is not always running
------------------------------------------------------------------------------ The NEW KODAK i700 Series Scanners deliver under ANY circumstances! Your production scanning environment may not be a perfect world - but thanks to Kodak, there's a perfect scanner to get the job done! With the NEW KODAK i700 Series Scanner you'll get full speed at 300 dpi even with all image processing features enabled. http://p.sf.net/sfu/kodak-com _______________________________________________ MonetDB-users mailing list MonetDB-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/monetdb-users
------------------------------------------------------------------------------ The NEW KODAK i700 Series Scanners deliver under ANY circumstances! Your production scanning environment may not be a perfect world - but thanks to Kodak, there's a perfect scanner to get the job done! With the NEW KODAK i700 Series Scanner you'll get full speed at 300 dpi even with all image processing features enabled. http://p.sf.net/sfu/kodak-com _______________________________________________ MonetDB-users mailing list MonetDB-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/monetdb-users
participants (4)
-
Fabian Groffen -
Mag Gam -
Martin Kersten -
Stefan de Konink