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| author | Tatjana Azundris Nuernberg <tatjana.nuernberg@oracle.com> | 2012-02-19 03:18:49 +0000 |
|---|---|---|
| committer | Tatjana Azundris Nuernberg <tatjana.nuernberg@oracle.com> | 2012-02-19 03:18:49 +0000 |
| commit | 5e6b6c5ea126ce73e236bf23a779947c5e341f56 (patch) | |
| tree | 9d7170183db986817bf9c46c0ffeaacb2d4e160a /sql/sql_parse.cc | |
| parent | 1141631802c7ac8caa6ae681ba75e059cc46ade8 (diff) | |
| download | mariadb-git-5e6b6c5ea126ce73e236bf23a779947c5e341f56.tar.gz | |
BUG 13454045 - 63524: BUG #35396 "ABNORMAL/IMPOSSIBLE/LARGE QUERY_TIME AND LOCK_TIME" HAPPENS A
If a query's end time is before before its start time, the system clock has been turn back
(daylight savings time etc.). When the system clock is changed, we can't tell for certain a
given query was actually slow. We did not protect against logging such a query with a bogus
execution time (resulting from end_time - start_time being negative), and possibly logging it
even though it did not really take long to run.
We now have a sanity check in place.
sql/sql_parse.cc:
Make sure end time is not before start time - otherwise, we can be SURE the system clock
was changed in between, but not by how much. In other words, when the clock is changed,
we don't know how long a query ran, and whether it was slow.
Diffstat (limited to 'sql/sql_parse.cc')
| -rw-r--r-- | sql/sql_parse.cc | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/sql/sql_parse.cc b/sql/sql_parse.cc index 989c3e0f42f..0f190809ab9 100644 --- a/sql/sql_parse.cc +++ b/sql/sql_parse.cc @@ -1734,8 +1734,9 @@ void log_slow_statement(THD *thd) ulonglong end_utime_of_query= thd->current_utime(); thd_proc_info(thd, "logging slow query"); - if (((end_utime_of_query - thd->utime_after_lock) > - thd->variables.long_query_time || + if ((((end_utime_of_query > thd->utime_after_lock) && + ((end_utime_of_query - thd->utime_after_lock) > + thd->variables.long_query_time)) || ((thd->server_status & (SERVER_QUERY_NO_INDEX_USED | SERVER_QUERY_NO_GOOD_INDEX_USED)) && opt_log_queries_not_using_indexes && |