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B-g#27501: 5.0 significantly more sys ("kernel") time than 4.1 \
      due to getrusage() calls

Even if profiling is turned off, the parser makes calls to reset 
the state at the beginning of each query.  That would eventually 
instantiate a PROFILE_ENTRY, which does indeed capture resource 
usage.

Instead, now check that profiling is active before progressing
far into the storage/expiration of old entries in the history.
This has the pleasant side-effect that queries to toggle profiling
are not recorded in the history.


mysql-test/r/profiling.result:
  Now after we turn off profiling, the beginning of the next query 
  refuses to enter the profiling code and it discards the info.
sql/sql_profile.cc:
  Add the same condition twice:  Once to abort storing previous 
  query information and the other to abort initialization for this 
  query that is starting.
  
  We do this symmetrically, before and after expiring old history 
  entries, so that the counts are correct.
This commit is contained in:
unknown 2007-04-03 19:50:55 -04:00
parent 8abb73142b
commit 46503d161e
2 changed files with 12 additions and 1 deletions
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2
mysql-test/r/profiling.result
View File

@ -248,6 +248,7 @@ sum(id)
12
show profiles;
Query_ID Duration Query
15 # select count(*) from t1
16 # insert into t1 select * from t1
17 # insert into t1 select * from t1
18 # insert into t1 select * from t1
@ -277,7 +278,6 @@ Query_ID Duration Query
42 # insert into t1 values (1), (2), (3)
43 # insert into t1 values (1), (2), (3)
44 # select * from t1
45 # set session profiling = OFF
set session profiling = ON;
select @@profiling;
@@profiling

11
sql/sql_profile.cc
View File

@ -493,6 +493,9 @@ void PROFILING::store()
while (history.elements > thd->variables.profiling_history_size)
delete history.pop();
if (likely(((thd)->options & OPTION_PROFILING) == 0))
DBUG_VOID_RETURN;
if (current != NULL)
{
if (keeping &&
@ -519,12 +522,20 @@ void PROFILING::store()
DBUG_VOID_RETURN;
}
/**
Store and clean up the old information and get ready to hold info about this
new query. This is called very often so it must be very lightweight if
profiling is not active.
*/
void PROFILING::reset()
{
DBUG_ENTER("PROFILING::reset");
store();
if (likely(((thd)->options & OPTION_PROFILING) == 0))
DBUG_VOID_RETURN;
if (current != NULL)
current->reset();
keep();