Dear all,
as a part of my project, i have to check the performance of monetdb column-store database. I am very new to this technology, so i dont know where the monetdb caches its previous query results..
I want to know how can i take results for cold runs on monetdb ( i have tried closing monetdb client and server every time i fire a query , but doesnt seem to clear the cache and i always get hot runs result)
so please can anyone help me regarding these.... suggestions are appreciated..
thanks in advance..
Prashant Rajkotiya M.tech. (ICT) DA-IICT ,Gandhinagar
Hi Prashant,
MonetDB does not cache query results, definitely not across client sessions, let alone across server restarts.
You operatings systems file system might do caching, though. Please refer to you file system and/or OS documentation for information on how to flush/empty these caches.
Best, Stefan
----- Original Message -----
Dear all,
as a part of my project, i have to check the performance of monetdb column-store database. I am very new to this technology, so i dont know where the monetdb caches its previous query results..
I want to know how can i take results for cold runs on monetdb ( i have tried closing monetdb client and server every time i fire a query , but doesnt seem to clear the cache and i always get hot runs result)
so please can anyone help me regarding these.... suggestions are appreciated..
thanks in advance..
Prashant Rajkotiya M.tech. (ICT) DA-IICT ,Gandhinagar
users-list mailing list users-list@monetdb.org https://www.monetdb.org/mailman/listinfo/users-list
Hello Stefan,
Thanks for your valuable suggestions. I will do the same as you have instructed. I have one more question regarding the same issue. I am also implementing the same on Postgres (Row-store database) and I also have the same problem with that. Please let me know if you know any tool which flushes the cache in postgres.
Thanks in advance. Prashant
On Wed, Sep 10, 2014 at 6:10 PM, Stefan Manegold Stefan.Manegold@cwi.nl wrote:
Hi Prashant,
MonetDB does not cache query results, definitely not across client sessions, let alone across server restarts.
You operatings systems file system might do caching, though. Please refer to you file system and/or OS documentation for information on how to flush/empty these caches.
Best, Stefan
----- Original Message -----
Dear all,
as a part of my project, i have to check the performance of monetdb column-store database. I am very new to this technology, so i dont know where the monetdb caches its previous query results..
I want to know how can i take results for cold runs on monetdb ( i have
tried
closing monetdb client and server every time i fire a query , but doesnt seem to clear the cache and i always get hot runs result)
so please can anyone help me regarding these.... suggestions are appreciated..
thanks in advance..
Prashant Rajkotiya M.tech. (ICT) DA-IICT ,Gandhinagar
users-list mailing list users-list@monetdb.org https://www.monetdb.org/mailman/listinfo/users-list
-- | Stefan.Manegold@CWI.nl | DB Architectures (DA) | | www.CWI.nl/~manegold/ | Science Park 123 (L321) | | +31 (0)20 592-4212 | 1098 XG Amsterdam (NL) |
users-list mailing list users-list@monetdb.org https://www.monetdb.org/mailman/listinfo/users-list
you can always try to restart the machine ,it might be longer , but you'll be sure no caching is in O/S level (btw, caching might be also at storage level if you got smart storage )
On Wed, Sep 10, 2014 at 3:49 PM, Prashant Patel pprashant9490@gmail.com wrote:
Hello Stefan,
Thanks for your valuable suggestions. I will do the same as you have instructed. I have one more question regarding the same issue. I am also implementing the same on Postgres (Row-store database) and I also have the same problem with that. Please let me know if you know any tool which flushes the cache in postgres.
Thanks in advance. Prashant
On Wed, Sep 10, 2014 at 6:10 PM, Stefan Manegold Stefan.Manegold@cwi.nl wrote:
Hi Prashant,
MonetDB does not cache query results, definitely not across client sessions, let alone across server restarts.
You operatings systems file system might do caching, though. Please refer to you file system and/or OS documentation for information on how to flush/empty these caches.
Best, Stefan
----- Original Message -----
Dear all,
as a part of my project, i have to check the performance of monetdb column-store database. I am very new to this technology, so i dont know where the monetdb caches its previous query results..
I want to know how can i take results for cold runs on monetdb ( i have
tried
closing monetdb client and server every time i fire a query , but doesnt seem to clear the cache and i always get hot runs result)
so please can anyone help me regarding these.... suggestions are appreciated..
thanks in advance..
Prashant Rajkotiya M.tech. (ICT) DA-IICT ,Gandhinagar
users-list mailing list users-list@monetdb.org https://www.monetdb.org/mailman/listinfo/users-list
-- | Stefan.Manegold@CWI.nl | DB Architectures (DA) | | www.CWI.nl/~manegold/ | Science Park 123 (L321) | | +31 (0)20 592-4212 | 1098 XG Amsterdam (NL) |
users-list mailing list users-list@monetdb.org https://www.monetdb.org/mailman/listinfo/users-list
users-list mailing list users-list@monetdb.org https://www.monetdb.org/mailman/listinfo/users-list
Instead of avoiding OS cache, I suggest using a bigger test dataset, and queries that force the OS to read the files from disk instead. Avoiding OS cache in eg: Linux is not straightforward AFAIK.
On 09/10/2014 01:58 PM, amihay gonen wrote:
you can always try to restart the machine ,it might be longer , but you'll be sure no caching is in O/S level (btw, caching might be also at storage level if you got smart storage )
On Wed, Sep 10, 2014 at 3:49 PM, Prashant Patel <pprashant9490@gmail.com mailto:pprashant9490@gmail.com> wrote:
Hello Stefan, Thanks for your valuable suggestions. I will do the same as you have instructed. I have one more question regarding the same issue. I am also implementing the same on Postgres (Row-store database) and I also have the same problem with that. Please let me know if you know any tool which flushes the cache in postgres. Thanks in advance. Prashant On Wed, Sep 10, 2014 at 6:10 PM, Stefan Manegold <Stefan.Manegold@cwi.nl <mailto:Stefan.Manegold@cwi.nl>> wrote: Hi Prashant, MonetDB does not cache query results, definitely not across client sessions, let alone across server restarts. You operatings systems file system might do caching, though. Please refer to you file system and/or OS documentation for information on how to flush/empty these caches. Best, Stefan ----- Original Message ----- > > > > Dear all, > > as a part of my project, i have to check the performance of monetdb > column-store database. I am very new to this technology, so i dont know > where the monetdb caches its previous query results.. > > I want to know how can i take results for cold runs on monetdb ( i have tried > closing monetdb client and server every time i fire a query , but doesnt > seem to clear the cache and i always get hot runs result) > > so please can anyone help me regarding these.... > suggestions are appreciated.. > > > thanks in advance.. > > Prashant Rajkotiya > M.tech. (ICT) > DA-IICT ,Gandhinagar > > > _______________________________________________ > users-list mailing list > users-list@monetdb.org <mailto:users-list@monetdb.org> > https://www.monetdb.org/mailman/listinfo/users-list > -- | Stefan.Manegold@CWI.nl | DB Architectures (DA) | | www.CWI.nl/~manegold/ <http://www.CWI.nl/%7Emanegold/> | Science Park 123 (L321) | | +31 (0)20 592-4212 <tel:%2B31%20%280%2920%20592-4212> | 1098 XG Amsterdam (NL) | _______________________________________________ users-list mailing list users-list@monetdb.org <mailto:users-list@monetdb.org> https://www.monetdb.org/mailman/listinfo/users-list _______________________________________________ users-list mailing list users-list@monetdb.org <mailto:users-list@monetdb.org> https://www.monetdb.org/mailman/listinfo/users-list
Hai Prashant,
As Stefan has pointed out, this's not a DBMS issue, but an OS issue. So, to get ice cold query exec. time, you can i) completely fill in your RAM with data other than what you want to query, or ii) let the OS flush the RAM. I've been using both options on Linux machines.
For option 1, I simply use a program to write zero's to all available RAM space. It can take some time, but this approach always works.
For option 2, I use the command: sudo /usr/bin/tee /proc/sys/vm/drop_caches I don't know if these commands are available on all Linux systems, and it also requires superuser permission.
Hope this helps a bit.
Regards,
Jennie
On Sep 10, 2014, at 14:49, Prashant Patel pprashant9490@gmail.com wrote:
Hello Stefan,
Thanks for your valuable suggestions. I will do the same as you have instructed. I have one more question regarding the same issue. I am also implementing the same on Postgres (Row-store database) and I also have the same problem with that. Please let me know if you know any tool which flushes the cache in postgres.
Thanks in advance. Prashant
On Wed, Sep 10, 2014 at 6:10 PM, Stefan Manegold Stefan.Manegold@cwi.nl wrote: Hi Prashant,
MonetDB does not cache query results, definitely not across client sessions, let alone across server restarts.
You operatings systems file system might do caching, though. Please refer to you file system and/or OS documentation for information on how to flush/empty these caches.
Best, Stefan
----- Original Message -----
Dear all,
as a part of my project, i have to check the performance of monetdb column-store database. I am very new to this technology, so i dont know where the monetdb caches its previous query results..
I want to know how can i take results for cold runs on monetdb ( i have tried closing monetdb client and server every time i fire a query , but doesnt seem to clear the cache and i always get hot runs result)
so please can anyone help me regarding these.... suggestions are appreciated..
thanks in advance..
Prashant Rajkotiya M.tech. (ICT) DA-IICT ,Gandhinagar
users-list mailing list users-list@monetdb.org https://www.monetdb.org/mailman/listinfo/users-list
-- | Stefan.Manegold@CWI.nl | DB Architectures (DA) | | www.CWI.nl/~manegold/ | Science Park 123 (L321) | | +31 (0)20 592-4212 | 1098 XG Amsterdam (NL) |
users-list mailing list users-list@monetdb.org https://www.monetdb.org/mailman/listinfo/users-list
users-list mailing list users-list@monetdb.org https://www.monetdb.org/mailman/listinfo/users-list
participants (5)
-
amihay gonen -
Miguel Ping -
Prashant Patel -
Stefan Manegold -
Ying Zhang