Re: Display Pg buffer cache (WIP)

Neil Conway wrote:
> If you do decide to hold the BufMappingLock, it might make
> sense to:
>
> 1. allocate an array of NBuffers elements
> 2. acquire BufferMappingLock in share mode
> 3. sequentially scan through the buffer pool, copying data into the array
> 4. release the lock
> 5. on each subsequent call to the SRF, format and return an element of
> the array
>
> Which should reduce the time to lock is held. This will require
> allocating NBuffers * size_of_stats memory (where size_of_stats will be
> something like 16 bytes).
>

That is a better approach, so I've used it in this new iteration.

In addition to holding the BufMappingLock, each buffer header is (spin)
locked before examining it, hopefully this is correct - BTW, I like the
new buffer lock design.

I'm still using BuildTupleFromCStrings, so there is considerable use of
sprintf conversion and "temporary" char * stuff. I would like this to be
a bit cleaner, so any suggestions welcome.

regards

Mark