| Bug #80721 | the new GET_LOCK implementation has a limit on the identifier name | ||
|---|---|---|---|
| Submitted: | 14 Mar 2016 8:13 | Modified: | 14 Mar 2016 14:08 |
| Reporter: | Miguel Angel Nieto | Email Updates: | |
| Status: | Not a Bug | Impact on me: | |
| Category: | MySQL Server: Locking | Severity: | S3 (Non-critical) |
| Version: | 5.7.11 | OS: | Any |
| Assigned to: | CPU Architecture: | Any | |
[14 Mar 2016 11:23]
Morgan Tocker
The new implementation is based on MDL, and thus has the same maximum length of table names. A workaround is to hash the lock-name using a function like SHA1. Here is an example: http://mysqlserverteam.com/making-get_lock-behavior-more-predictable-cross-version-with-qu...
[14 Mar 2016 14:08]
MySQL Verification Team
Hello Miguel, Thank you for the bug report and feedback. As Morgan explained(with possible workaround), this is a documented behavior i.e MySQL 5.7.5 and later enforces a maximum length on lock names of 64 characters. Previously, no limit was enforced. Please see http://dev.mysql.com/doc/refman/5.7/en/miscellaneous-functions.html#function_get-lock and some more details are here - https://dev.mysql.com/doc/refman/5.7/en/upgrading-from-previous-series.html Thanks, Umesh
Description: MySQL 5.7 includes a patch for GET_LOCK that changes its behaviour but also places a limit on the identificator name that didn't exist before. In my personal opinion, that limitation could be removed. How to repeat: 5.6 > select GET_LOCK(repeat('x', 195), 1); +-------------------------------+ | GET_LOCK(repeat('x', 195), 1) | +-------------------------------+ | 1 | +-------------------------------+ 5.7: > select GET_LOCK(repeat('x', 195), 1); ERROR 1059 (42000): Identifier name 'xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx' is too long Suggested fix: Remove the limitation.