"Kevin Grittner" wrote:
> I'm proceeding on this basis.
Result attached. I found myself passing around the tuple xmin value
just about everywhere that the predicate lock target tag was being
passed, so it finally dawned on me that this logically belonged as
part of the target tag. That simplified the changes, and the net
result of following Heikki's suggestion here is the reduction of
total lines of code by 178 while adding coverage for missed corner
cases and fixing bugs.
Thanks again, Heikki!
I will test this some more tomorrow. So far I haven't done more than
ensure it passes the standard regression tests and the isolation
tests added for SSI. The latter took awhile because the hash_any
function was including uninitialized bytes past the length of the tag
in its calculations. We should probably either fix that or document
it. I had to add another couple bytes to the tag to get it to a four
byte boundary to fix it. Easy once you know that's how it works...
The attached patch can also be viewed here:
http://git.postgresql.org/gitweb?p=users/kgrittn/postgres.git;a=commitdiff;h=46fd5ea6728b566c521ec83048bc00a207289dd9
If this stands up to further testing, the only issue I know of for
the 9.1 release is to update the documentation of shared memory usage
to include the new structures.
-Kevin