On Wed, Dec 18, 2019 at 12:06 PM Tom Lane <t...@sss.pgh.pa.us> wrote: > It seems like it'd be worth subdividing "<anonymous>" into the actual > anonymous allocations and the allocator overhead (which is both > padding and whatever the shmem allocator itself eats). Maybe call > the latter "<overhead>". After which, I'd be tempted to call the > free space "<free>" rather than giving it a null name.
Here's a new version that takes a slightly different approach: it adds an additional column to the view for "allocated_size," so that you can see both what was requested and what you actually got. With this approach, you can do interesting things like: select *, off - lag(off + allocated_size, 1) over () as hole_size from (select * from pg_shmem_allocations order by 2) x; ...which didn't work very well with the previous version. All of this makes me think that we might want to do some followup to (1) convert anonymous allocations to non-anonymous allocations, for inspectability, and (2) do some renaming to get better stylistic agreement between the names of various shared memory chunks. But I think that work is properly done after this patch is committed, not before. -- Robert Haas EnterpriseDB: http://www.enterprisedb.com The Enterprise PostgreSQL Company
v3-0001-Add-a-pg_shmem_allocations-view.patch
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