MySQL Bugs: #57155: Docs improvement request for SELECT NOW() being affected by SET TIMESTAMP

Bug #57155	Docs improvement request for SELECT NOW() being affected by SET TIMESTAMP
Submitted:	30 Sep 2010 23:10	Modified:	5 Jul 2011 16:49
Reporter:	Roel Van de Paar	Email Updates:
Status:	Closed	Impact on me:	None
Category:	MySQL Server: Documentation	Severity:	S4 (Feature request)
Version:		OS:	Any
Assigned to:	Paul DuBois	CPU Architecture:	Any

Description:
"In addition, the SET TIMESTAMP statement affects the value returned by NOW() but not by SYSDATE(). This means that timestamp settings in the binary log have no effect on invocations of SYSDATE()."

http://dev.mysql.com/doc/refman/5.1/en/date-and-time-functions.html#function_now

Could we clarify this section?

What happens is that:

SET TIMESTAMP=1259819684;
SELECT NOW();
SELECT NOW();

Will keep returning the same time until you run:

SET TIMESTAMP=0;

How to repeat:
SET TIMESTAMP=1259819684;
SELECT NOW();
SELECT NOW();
[...]
SELECT NOW();
SET TIMESTAMP=0;
SELECT NOW();

Suggested fix:
The paragraph above hints at the issue but does not spell it out, it would be great if it did.

(http://forums.mysql.com/read.php?149,292500,294139#msg-294139)

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.

Additional text:

Setting the timestamp to a nonzero value causes each subsequent
invocation of NOW() to return that value. Setting the timestamp to
zero cancels this effect so that NOW() once again returns the current
date and time.