db-derby-commits mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Apache Wiki <wikidi...@apache.org>
Subject [Db-derby Wiki] Update of "DerbyBug47" by JamesSynge
Date Sun, 01 Oct 2006 14:53:13 GMT
Dear Wiki user,

You have subscribed to a wiki page or wiki category on "Db-derby Wiki" for change notification.

The following page has been changed by JamesSynge:
http://wiki.apache.org/db-derby/DerbyBug47

------------------------------------------------------------------------------
  {{{literals-10-trace.txt}}} for 10 parameters using the Literals strategy.
  {{{markers-10-trace.txt}}} for 10 parameters using the Markers strategy.
  
- The 
- What is most interesting is how wrong the 
+ What is most interesting is how the cost estimate for Markers is so wrong
+ compared to the actual time taken to execute the queries:
  
- ||Strategy||cost||rowCount||
+ ||Strategy||cost||rowCount||Total ms (avg)||
- ||Literals||110472||7500||
+ ||Literals||110472||7500||1021||
- ||Markers||14||3.4||
+ ||Markers||14||3.4||3075||
  
- 
- Here are the results for different numbers of parameters (the ID Count column below), on
a table of 100,000 rows, using
- embedded Derby.
+ Here are the timings for all of the strategies for different numbers of parameters
+ (the ID Count column below), on a table of 100,000 rows, using
+ embedded Derby.  There were 29689 unique values for the column
- There were 29689 unique values for the column used in the where clause, so on average each
value was in a bit more than 3 rows.
+ used in the where clause, so on average each value was in a bit more than 3 rows.
  
  || ||||Literals||||Literal||||Markers||||Marker||||Join Temp||||Join Scratch||||Join Savepoint||||Nested
Temp||||Nested Scratch||||Nested Savepoint||
  ||ID Count||Total ms||ms / ID||Total ms||ms / ID||Total ms||ms / ID||Total ms||ms / ID||Total
ms||ms / ID||Total ms||ms / ID||Total ms||ms / ID||Total ms||ms / ID||Total ms||ms / ID||Total
ms||ms / ID||

Mime
View raw message