Defines how many worker threads the server should use to perform main
Thanks Stefan and Brian.
When I went through monetdb man page, the usage of nthreads (set as
gdk_nr_threads) environmental variable was defined as
processing. Normally, this number equals the number of available CPU cores
in the system. Reducing this number forces the server to use less
parallelism when executing queries, or none at all if set to *1*.
I am a bit confused in understanding this statement. The variable
"nthreads" controls
1. the number of threads processing a single query using multiple cores.
2. the number of queries currently being executed over all databases by
the mserver.
Please help me understand which of these two is correct..
This doubt arises because I have read from MonetDB home page that "MonetDB
is designed for multi-core parallel execution on desktops to reduce
response time for complex query processing".
If the variable "nthreads" controls the latter, then does monetdb have an
in built queue to store the queries from remaining connections (controlled
by the variable nclients) to the mserver?? I have read about multiplex
funnel and a bit afraid over the transactional disadvantages mentioned in
there..
Is there any other solution?
Thanks & Regards,
Vijayakrishna.P.
Mobile : (+91) 9500402305.
On Tue, Aug 11, 2015 at 6:56 PM, Stefan Manegold
Hi,
indeed;
see also `man mserver5` and `man monetdb` or https://www.monetdb.org/Documentation/mserver5-man-page and https://www.monetdb.org/Documentation/monetdb-man-page
Stefan
----- On Aug 11, 2015, at 3:11 PM, Brian Hood brianh6854@googlemail.com wrote:
Hi Vijay,
Well if you take a look at your merovingian.log you can see the command that starts the database.
/usr/bin/mserver5 --dbpath=/data2/threatmonitor/threatmonitor --set merovingian_uri=mapi:monetdb://orville.lan:50000/threatmonitor --set mapi_open=false --set mapi_port=0 --set mapi_usock=/data2/threatmonitor/threatmonitor/.mapi.sock --set monet_vault_key=/data2/threatmonitor/threatmonitor/.vaultkey --set gdk_nr_threads=2 --set max_clients=64 --set sql_optimizer=default_pipe --set monet_daemon=yes
These 2 i think are the ones your looking for.
--set gdk_nr_threads=2 --set max_clients=64
Regards,
Brian Hood
On Tue, Aug 11, 2015 at 7:14 AM, Vijay Krishna < vijayakrishna55@gmail.com > wrote:
Oops.. My bad.. Thanks Brian..
Yes I was indeed looking for connection pools... Something like maximum thread concurrency option in innodb...
Is there any such available with MonetDB?
I had gone through this option... mserver5 --set max_clients=<num> Is this the only way to control parallel threads??
Thanks & Regards,
Vijayakrishna.P. Mobile : (+91) 9500402305 .
On Mon, Aug 10, 2015 at 7:48 PM, Brian Hood < brianh6854@googlemail.com wrote:
Hi Vijay,
I think the words your looking for a connection pooling.
InnoDB Buffer pool in MySQL is the amount of data stored in memory which you set to a certain size and has nothing to do with network traffic.
Regards,
Brian Hood
On Mon, Aug 10, 2015 at 8:45 AM, Vijay Krishna < vijayakrishna55@gmail.com > wrote:
Hi,
Does MonetDB have any built in buffer pools to handle parallel requests?
I see the default number of parallel connections accepted and processed at a time by MonetDB is 64.. While I see that there are ways to increase it, is there anyway built in to pool incoming requests until the live 64 requests are processed?
For example, our application would receive 100 requests at a time, while we wish to limit the number of queries handled at a time by MonetDB to 50. Is there any way to automatically handle the remaining 50 (something like innodb buffer pool) ??
Thanks & Regards,
Vijayakrishna.P. Mobile : (+91) 9500402305 .
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