Bug #27638: slow logging to CSV table inserts bad query_time and lock_time values

When MySQL logged slow query information to a CSV table, it stored the
query_time and lock_time values with an incorrect formula.

If the time was over 59 seconds, this caused incorrect statistics (either the
slow query was not logged, or the time was far from correct).  This change
fixes the method used to store those TIME values in the slow_log table.

2 files changed, 17 insertions, 2 deletions

diff --git a/sql/log.cc b/sql/log.cc
index 57f16a1e11e..3cfcabd8363 100644
--- a/sql/log.cc
+++ b/sql/log.cc
@@ -569,11 +569,21 @@ bool Log_to_csv_event_handler::
 
   if (query_start_arg)
   {
+    /*
+      A TIME field can not hold the full longlong range; query_time or
+      lock_time may be truncated without warning here, if greater than
+      839 hours (~35 days)
+    */
+    TIME t;
+    t.neg= 0;
+
     /* fill in query_time field */
-    if (table->field[2]->store(query_time, TRUE))
+    calc_time_from_sec(&t, (long) min(query_time, (longlong) TIME_MAX_VALUE_SECONDS), 0);
+    if (table->field[2]->store_time(&t, MYSQL_TIMESTAMP_TIME))
       goto err;
     /* lock_time */
-    if (table->field[3]->store(lock_time, TRUE))
+    calc_time_from_sec(&t, (long) min(lock_time, (longlong) TIME_MAX_VALUE_SECONDS), 0);
+    if (table->field[3]->store_time(&t, MYSQL_TIMESTAMP_TIME))
       goto err;
     /* rows_sent */
     if (table->field[4]->store((longlong) thd->sent_row_count, TRUE))
diff --git a/sql/time.cc b/sql/time.cc
index 4854206b1c8..ef2c87673d5 100644
--- a/sql/time.cc
+++ b/sql/time.cc
@@ -313,6 +313,11 @@ void localtime_to_TIME(TIME *to, struct tm *from)
 void calc_time_from_sec(TIME *to, long seconds, long microseconds)
 {
   long t_seconds;
+  // to->neg is not cleared, it may already be set to a useful value
+  to->time_type= MYSQL_TIMESTAMP_TIME;
+  to->year= 0;
+  to->month= 0;
+  to->day= 0;
   to->hour= seconds/3600L;
   t_seconds= seconds%3600L;
   to->minute= t_seconds/60L;