[MonetDB-users] Algebra Mode vs sql debug 16384
Hi All - can someone help me clarify the difference between Algebra "-G" mode and setting SQL debug equal to 16384 in the monetdb config file?
With an older version of MonetDb I set the sql_debug=16384 in the config file so I could take advantage of Algebra mode when starting the server via mero.
Today I compiled the Nov08-SP2 release and ran some tests using sql_debug=0 vs sql_debug=16384. I assumed they would do the exact same since Algebra mode is now the default. They returned very different results however.
For SQL statements with a large number of predicates (100+), performance is about the same. But for anything smaller the query speed is much worse (10x avg) when I don't have sql_debug=16384 turned on.
The query trace files are also different when I run the exact same query with and without the 16384 flag. I made sure to restart the server process in between.
Also, below is the latest output from mserver --version:
Copyright (c) 1993-July 2008 CWI Copyright (c) August 2008- MonetDB B.V., all rights reserved Visit http://monetdb.cwi.nl/ for further information Configured for prefix: /home/ross/monetNov08sp2 Libraries: openssl: OpenSSL 0.9.8g 19 Oct 2007 (compiled with OpenSSL 0.9.8g 19 Oct 2007) Compiled by: ross@home Compilation: gcc -O2 -std=c99 -fgnu89-inline -O6 -fomit-frame-pointer -finline-functions -falign-loops=4 -falign-jumps=4 -falign-functions=4 -fexpensive-optimizations -funroll-loops -frerun-cse-after-loop -frerun-loop-opt -ftree-vectorize Linking : /usr/bin/ld
Any thoughts?
Best Regards, Ross
On Thu, Feb 05, 2009 at 11:39:09AM -0600, Ross Bates wrote:
Hi All - can someone help me clarify the difference between Algebra "-G" mode and setting SQL debug equal to 16384 in the monetdb config file? With an older version of MonetDb I set the sql_debug=16384 in the config file so I could take advantage of Algebra mode when starting the server via mero. Today I compiled the Nov08-SP2 release and ran some tests using sql_debug=0 vs sql_debug=16384. I assumed they would do the exact same since Algebra mode is now the default. They returned very different results however. For SQL statements with a large number of predicates (100+), performance is about the same. But for anything smaller the query speed is much worse (10x avg) when I don't have sql_debug=16384 turned on.
The Algebra because default in the current stable (and the development up to it). So the Nov08 doesn't have this by default. So I don't think its strang that the 16384 setting (ie enabling algebra) works better. Anyway if your in a testing phase, please consider the current cvs stable branch. It could improve the release later this month.
Niels
The query trace files are also different when I run the exact same query with and without the 16384 flag. I made sure to restart the server process in between. Also, below is the latest output from mserver --version: Copyright (c) 1993-July 2008 CWI Copyright (c) August 2008- MonetDB B.V., all rights reserved Visit [1]http://monetdb.cwi.nl/ for further information Configured for prefix: /home/ross/monetNov08sp2 Libraries: openssl: OpenSSL 0.9.8g 19 Oct 2007 (compiled with OpenSSL 0.9.8g 19 Oct 2007) Compiled by: ross@home Compilation: gcc -O2 -std=c99 -fgnu89-inline -O6 -fomit-frame-pointer
-finline-functions -falign-loops=4 -falign-jumps=4 -falign-functions=4 -fexpensive-optimizations -funroll-loops -frerun-cse-after-loop -frerun-loop-opt -ftree-vectorize Linking : /usr/bin/ld Any thoughts? Best Regards, Ross
References
Create and Deploy Rich Internet Apps outside the browser with Adobe(R)AIR(TM) software. With Adobe AIR, Ajax developers can use existing skills and code to build responsive, highly engaging applications that combine the power of local resources and data with the reach of the web. Download the Adobe AIR SDK and Ajax docs to start building applications today-http://p.sf.net/sfu/adobe-com _______________________________________________ MonetDB-users mailing list MonetDB-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/monetdb-users
just a short MIL question:
I have a table <attr1 | attr2 | attr3> vertically fragmented into three BATs. Now I would like to get the the table sorted on both attr1, attr2, like this:
attr1 attr2 attr3 1 1 0.2 1 2 0.3 2 1 0.4 2 3 0.1
How do I do this with the 3 BATs in MIL. Does anyone has an example MIL code of such an operation?
Hi Henning,
here is an example:
var ord := attr1.tsort(); ord := ord.CTrefine(attr2).mark(0@0).reverse(); attr1 := ord.leftfetchjoin(attr1); attr2 := ord.leftfetchjoin(attr2); attr3 := ord.leftfetchjoin(attr3);
Jan
On Feb 6, 2009, at 17:21, Henning Rode wrote:
just a short MIL question:
I have a table <attr1 | attr2 | attr3> vertically fragmented into three BATs. Now I would like to get the the table sorted on both attr1, attr2, like this:
attr1 attr2 attr3 1 1 0.2 1 2 0.3 2 1 0.4 2 3 0.1
How do I do this with the 3 BATs in MIL. Does anyone has an example MIL code of such an operation?
Create and Deploy Rich Internet Apps outside the browser with Adobe(R)AIR(TM) software. With Adobe AIR, Ajax developers can use existing skills and code to build responsive, highly engaging applications that combine the power of local resources and data with the reach of the web. Download the Adobe AIR SDK and Ajax docs to start building applications today-http://p.sf.net/sfu/adobe-com _______________________________________________ MonetDB-users mailing list MonetDB-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/monetdb-users
I found already a solution.
On 06.02.2009, at 17:21, Henning Rode wrote:
just a short MIL question:
I have a table <attr1 | attr2 | attr3> vertically fragmented into three BATs. Now I would like to get the the table sorted on both attr1, attr2, like this:
attr1 attr2 attr3 1 1 0.2 1 2 0.3 2 1 0.4 2 3 0.1
How do I do this with the 3 BATs in MIL. Does anyone has an example MIL code of such an operation?
Create and Deploy Rich Internet Apps outside the browser with Adobe(R)AIR(TM) software. With Adobe AIR, Ajax developers can use existing skills and code to build responsive, highly engaging applications that combine the power of local resources and data with the reach of the web. Download the Adobe AIR SDK and Ajax docs to start building applications today-http://p.sf.net/sfu/adobe-com _______________________________________________ MonetDB-users mailing list MonetDB-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/monetdb-users
participants (5)
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Henning Rode -
Henning Rode -
Jan Rittinger -
Niels Nes -
Ross Bates