In postgres I could use explain analyze to see actions performed by database and their cost. I was not able to run explain analyze. I ran EXPLAIN, but can not see any plan or cost. Any ideas how to get costs and query plan like in Postgres?
See the documentation:https://www.monetdb.org/Documentation/Cookbooks/SQLrecipes/QueryTiming MonetDB does not contain a cost-based optimizer as you find in other systems. You can use both 'EXPLAIN SELECT....' and 'TRACE SELECT ....' to get insight into the expensive components. On 30/04/16 12:41, Shmagi Kavtaradze wrote:
Thanks for answer. I ran "trace select count(*) from view" and it returned "user | statement" that I really could not understand. In documentation I saw it should return : create function sys.tracelog() returns table ( event integer, -- event counter clk varchar(20), -- wallclock, no mtime in kernel pc varchar(50), -- module.function[nr] thread int, -- thread identifier ticks bigint, -- time in microseconds rrsMB bigint, -- resident memory in MB vmMB bigint, -- virtual size in MB reads bigint, -- number of blocks read writes bigint, -- number of blocks written minflt bigint, -- minor page faults majflt bigint, -- major page faults nvcsw bigint, -- non-volantary conext switch stmt string -- actual statement executed ) Any idea how to get user friendly answer for trace? On Sat, Apr 30, 2016 at 2:18 PM, Martin Kersten <martin.kersten@cwi.nl> wrote:
On 30/04/16 23:52, Shmagi Kavtaradze wrote:
Thanks for answer. I ran "trace select count(*) from view" and it returned "user | statement" that I really could not understand. In documentation I saw it should return :
What you see is the projection over clk/stmt of the underlying tracelog table. This is sufficient for understanding where the time goes. See updated doc page or further https://www.monetdb.org/Documentation/Manuals/MonetDB/Profiler/TraceFormat
Still not sure how to do it. Tried "TRACE inblock, outblock from (select bitand(a.sentddec, b.sentddec) as res from chunks10000 a, chunks10000 b where a.chunkid=b.chunkid AND a.sentid<b.sentid);" But I guess I am doing something wrong.
sql>trace select 1; +--------------+ | single_value | +==============+ | 1 | +--------------+ 1 tuple (3.545ms) +-------+--------------------------------------------------------------------------------------+ | ticks | statement | +=======+======================================================================================+ | 1 | X_10=0@0:void := querylog.define("trace select 1;":str,"default_pipe":str,4:int); | | 6 | sql.resultSet(".L":str,"single_value":str,"tinyint":str,8:int,0:int,7:int,A0=1:bte); | | 1 | end user.s2_1; | | 751 | function user.s2_1{autoCommit=true}(A0:bte):void; | | 886 | X_4=0@0:void := user.s2_1(1:bte); | +-------+--------------------------------------------------------------------------------------+ 5 tuples (3.659ms) sql>select * from sys.tracelog(); +-------+---------------+---------------+--------+-------+-------+------+-------+--------+--------+--------+-------+--------------------------------------------------------------------------------------+ | event | clk | pc | thread | ticks | rrsmb | vmmb | reads | writes | minflt | majflt | nvcsw | stmt | +=======+===============+===============+========+=======+=======+======+=======+========+========+========+=======+======================================================================================+ | 0 | 10:37:07.375 | user.s2_1[1]5 | 3 | 1 | 53 | 0 | 0 | 0 | 0 | 0 | 0 | X_10=0@0:void := querylog.define("trace select 1;":str,"default_pipe":str,4:int); | | 1 | 10:37:07.375 | user.s2_1[2]5 | 3 | 6 | 53 | 0 | 0 | 80 | 10 | 0 | 0 | sql.resultSet(".L":str,"single_value":str,"tinyint":str,8:int,0:int,7:int,A0=1:bte); | | 2 | 10:37:07.375 | user.s2_1[3]5 | 3 | 1 | 53 | 0 | 0 | 0 | 0 | 0 | 0 | end user.s2_1; | | 3 | 10:37:07.375 | user.s2_1[0]5 | 3 | 751 | 53 | 0 | 0 | 0 | 0 | 0 | 0 | function user.s2_1{autoCommit=true}(A0:bte):void; | | 4 | 10:37:07.375 | user.main[3]4 | 3 | 886 | 53 | 0 | 0 | 0 | 0 | 0 | 0 | X_4=0@0:void := user.s2_1(1:bte); | +-------+---------------+---------------+--------+-------+-------+------+-------+--------+--------+--------+-------+--------------------------------------------------------------------------------------+ 5 tuples (4.906ms) ----- On May 1, 2016, at 9:12 PM, Shmagi Kavtaradze kavtaradze.s@gmail.com wrote:
-- | Stefan.Manegold@CWI.nl | DB Architectures (DA) | | www.CWI.nl/~manegold/ | Science Park 123 (L321) | | +31 (0)20 592-4212 | 1098 XG Amsterdam (NL) |
participants (4)
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Martin Kersten -
Martin Kersten -
Shmagi Kavtaradze -
Stefan Manegold