MySQL Bugs: #28409: global variables of SHOW SESSION STATUS are not documented

Bug #28409	global variables of SHOW SESSION STATUS are not documented
Submitted:	14 May 2007 7:14	Modified:	8 Aug 2007 3:07
Reporter:	Jan Kneschke	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: Documentation	Severity:	S3 (Non-critical)
Version:		OS:	Any
Assigned to:	Paul DuBois	CPU Architecture:	Any

Description:
On

http://dev.mysql.com/doc/refman/5.1/en/show-status.html

it reads:

  "Some status variables have only a global value. For these, you get the same value for both GLOBAL and SESSION."

Only a comment on

http://dev.mysql.com/doc/refman/5.1/en/server-status-variables.html

puts some light on this topic. 

How to repeat:
Check the URLs

Suggested fix:
Document all non-session variables which are listing the SHOW SESSION STATUS.

Thank you for the report.

There is next text above the quote which you provided:

With the GLOBAL modifier, SHOW STATUS displays the status values for all connections to MySQL. With SESSION, it displays the status values for the current connection. If no modifier is present, the default is SESSION. LOCAL is a synonym for SESSION.

Please confirm if this is not clear for you or desribe more accurately what do you want to change in the manual.

All innodb_* and key_* status counters are always global:

mysql> show global status like "Key_%";
+------------------------+-------+
| Variable_name          | Value |
+------------------------+-------+
| Key_blocks_not_flushed | 0     |
| Key_blocks_unused      | 14345 |
| Key_blocks_used        | 7     |
| Key_read_requests      | 5040  |
| Key_reads              | 34084 |
| Key_write_requests     | 38348 |
| Key_writes             | 18    |
+------------------------+-------+
7 rows in set (0.00 sec)

mysql> show session status like "Key_%";
+------------------------+-------+
| Variable_name          | Value |
+------------------------+-------+
| Key_blocks_not_flushed | 0     |
| Key_blocks_unused      | 14345 |
| Key_blocks_used        | 7     |
| Key_read_requests      | 5040  |
| Key_reads              | 34084 |
| Key_write_requests     | 38348 |
| Key_writes             | 18    |
+------------------------+-------+
7 rows in set (0.01 sec)

The documentation only says that "some" a always global, but it doesn't say which of them.

Thank you for the additional explanation.

Verified as described.

Thank you for your bug report. This issue has been addressed in the documentation. The updated documentation will appear on our website shortly, and will be included in the next release of the relevant products.

The global/session scope of the status variables now is listed here:

http://dev.mysql.com/doc/refman/5.0/en/server-status-variables.html
http://dev.mysql.com/doc/refman/5.1/en/server-status-variables.html