Thanks，professor Stefan Manegold,when I use explain,I get the optimizer MAL
plan.
I have another question, so we know that many classic optimizer for
row-oriented database，and can I say the MAL optimizer is unique for
column-oriented database such as MonetDB? or some of MAL optimizer is unique
for column-oriented?
Best regards!
2010/8/11 Stefan Manegold
On Wed, Aug 11, 2010 at 04:23:42PM +0800, kun ren wrote:
I read sql_optimizer setting in monetdb5.conf ,and default setting is: sql_optimizer=default_pipe
default_pipe=inline,remap,evaluate,costModel,coercions,emptySet,aliases,mitosis,mergetable,deadcode,commonTerms,joinPath,reorder,deadcode,reduce,garbageCollector,dataflow,history,multiplex
so there are many optimizer,but why when i debug MonetDB,and dump the mal
my sql statement,but i can't find the optimizer mal ,and don't enter
of the
optimizer? like there are no optimizer,
if you prefix your SQL query with EXPLAIN to see the MAL plan, you get the optimizer MAL plan, i.e., all optimizers have already been called and done their work.
Stefan
2010/8/11 Stefan Manegold
Yes, if you write MAL "by hand" (or have some program create it) that
does
explicitly call a MAL optimizer, that MAL optimizer is indeed used to optimize the MAL code according to its very purpose.
Stefan
On Wed, Aug 11, 2010 at 03:49:47PM +0800, kun ren wrote:
It is only used by SQL? and how to designation the optimiser？but when I write MAL,for example, i:=0; b:= "done"; barrier go:= true; c:=i+1; d:="step"; v:=d; io.print(v); i:=c; redo go:= i<2; exit go; io.print(b); optimizer.aliasRemoval();
the last optimizer.aliasRemoval() is used for optimizing?
2010/8/11 Fabian Groffen
Recently,I am intersting in MAL optimize，and have read the manual of
On 11-08-2010 15:25:15 +0800, kun ren wrote: the
MAL optimize, but it is so long, Possible if we want to use mal optimize ,we must degignation the optimize consideration, such as alias removal, constant expression,join path optimizer;And then I dedug the MonetDB,but default it don't use any optimize.so what do you think about the mal optimize?
It is only used when you use SQL. The sql_optimizer setting in monetdb5.conf controls which optimisers are run, which by default are quite a few.
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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) 592-4199 |
-- | 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) 592-4199 |