Re: What's the XID?

[Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>]

Andrew Sullivan <ajs(at)crankycanuck(dot)ca> writes:
> On Wed, Dec 26, 2007 at 05:48:14PM -0800, ivan.hou wrote:
>> if i executed "select * from mydb" twice, the XID wil be increased by 2

> Yep.  Whereas if you did

> 	BEGIN;
> 	SELECT 1;
> 	SELECT 1;
> 	COMMIT;
	
> the xid would be increased by 1.

But note that as of 8.3, SELECT-only transactions won't acquire an
XID and hence won't advance the counter.  So if you're thinking of
writing code that depends on that behavior, don't.

			regards, tom lane