MySQL Bugs: #73275: Difference in length\'s of the variable_value in user_variables_by

Bug #73275	Difference in length\'s of the variable_value in user_variables_by_thread table
Submitted:	11 Jul 2014 10:47	Modified:	24 Jul 2014 3:44
Reporter:	Tarique Saleem	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: Performance Schema	Severity:	S3 (Non-critical)
Version:	5.7.5	OS:	Any
Assigned to:		CPU Architecture:	Any

Description:
I see a difference in length's. I am not sure if it has to do with maximum value supported by Blob.
But If that is the case the use of this table where it will be used to transmit values may not be possible. 

Observed in WL6884 branch
-------------------------
revision-id: marc.alff@oracle.com-20140707153333-ooh7tx971p81pa6a
date: 2014-07-07 17:33:33 +0200
build-date: 2014-07-09 15:17:20 +0530
revno: 6972
branch-nick: mysql-trunk-wl6884

MySQL source 5.7.5-m15

How to repeat:

mysql> set @a=repeat('aaaa',1000000);
Query OK, 0 rows affected (0.03 sec)

mysql> select length(@a);
+------------+
| length(@a) |
+------------+
|    4000000 |
+------------+
1 row in set (0.00 sec)

mysql> select VARIABLE_NAME,length(VARIABLE_VALUE) from performance_schema.user_variables_by_thread;
+---------------+------------------------+
| VARIABLE_NAME | length(VARIABLE_VALUE) |
+---------------+------------------------+
| a             |                  65535 |
+---------------+------------------------+
1 row in set (0.01 sec)

Fixed on developer branch.

Bug affects no released version. No changelog entry needed.