Robert Haas <robertmhaas@gmail.com> wrote:
> I think I've cleared out most of the small stuff.
Thanks!
> The two SSI related issues still on the open items list are:
>
> * SSI: failure to clean up some SLRU-summarized locks
This one is very important. Not only could it lead to unnecessary
false positive serialization failures, but (more importantly) it
leaks shared memory by not clearing some locks, leading to potential
"out of shared memory" errors.
While this isn't as small as most of the SSI patches, I'm going to
point out (to reassure those who haven't been reading the patches)
that this one modifies two lines, adds six Assert statements which
Dan found useful in debugging the issue, and adds (if you ignore
white space and braces) four lines of code. "Big" is a relative
term here. The problem is that the code in which these tweaks fall
is hard to get one's head around.
> * SSI: three different HTABs contend for shared memory in a
> free-for-all
I think we're pretty much agreed that something should be done about
this, but the main issue here is that if either heavyweight locks or
SIRead predicate locks exhaust memory, the other might be unlucky
enough to get the error, making it harder to identify the cause.
Without the above bug or an unusual workload, it would tend not to
make a difference.
If things come down to the wire and this is the only thing holding
up the beta release, I'd suggest going ahead and cutting the beta.
-Kevin