MDEV-34621: Fix division by zero in mariadb-slap when iterations=0

The mariadb-slap tool crashes with a floating point exception when run with -i0 due to division by zero in the generate_stats() function.
Initial attempts to fix this by changing the minimum value in the option definition caused unexpected warning messages even with valid values.
This fix adds a simple safety check that prevents division by zero when iterations=0, setting the average timing to 0 instead of attempting the division. This approach avoids both the crash and the unexpected warnings.

Author: KhaledR57

client/mysqlslap.c

@@ -2219,6 +2219,16 @@ generate_stats(conclusions *con, option_string *eng, stats *sptr)
   stats *ptr;
   unsigned int x;
 
+  /* Early return when iterations is 0 to avoid accessing uninitialized sptr */
+  if (iterations == 0)
+  {
+    if (eng && eng->string)
+      con->engine= eng->string;
+    else
+      con->engine= NULL;
+    return;
+  }
+
   con->min_timing= sptr->timing; 
   con->max_timing= sptr->timing;
   con->min_rows= sptr->rows;
@@ -2238,6 +2248,7 @@ generate_stats(conclusions *con, option_string *eng, stats *sptr)
     if (ptr->timing < con->min_timing)
       con->min_timing= ptr->timing;
   }
+
   con->avg_timing= con->avg_timing/iterations;
 
   if (eng && eng->string)

mysql-test/main/mysqlslap.result

@@ -260,3 +260,6 @@ DROP TABLE t1;
 #
 # Bug MDEV-15789 (Upstream: #80329): MYSQLSLAP OPTIONS --AUTO-GENERATE-SQL-GUID-PRIMARY and --AUTO-GENERATE-SQL-SECONDARY-INDEXES DONT WORK
 #
+#
+# Bug MDEV-34621: Fix division by zero in mariadb-slap when iterations=0
+#

mysql-test/main/mysqlslap.test

@@ -88,3 +88,11 @@ DROP TABLE t1;
 --exec $MYSQL_SLAP --concurrency=1 --silent --iterations=1 --number-int-cols=2 --number-char-cols=3 --auto-generate-sql --auto-generate-sql-guid-primary --create-schema=slap
 
 --exec $MYSQL_SLAP --concurrency=1 --silent --iterations=1 --number-int-cols=2 --number-char-cols=3 --auto-generate-sql --auto-generate-sql-secondary-indexes=1 --create-schema=slap
+
+--echo #
+--echo # Bug MDEV-34621: Fix division by zero in mariadb-slap when iterations=0
+--echo #
+
+--exec $MYSQL_SLAP -i0 --only-print
+
+--exec $MYSQL_SLAP --silent --concurrency=5 --iterations=0 --number-int-cols=2 --number-char-cols=3 --auto-generate-sql --auto-generate-sql-add-autoincrement --auto-generate-sql-load-type=mixed