On Fri, Mar 27, 2026 at 12:31 PM Ashutosh Bapat <[email protected]> wrote: > > On Wed, Mar 25, 2026 at 9:35 PM Ashutosh Bapat > <[email protected]> wrote: > > > > On Tue, Mar 24, 2026 at 9:02 PM Ashutosh Bapat > > <[email protected]> wrote: > > > > > > > > > I will continue from 0008 tomorrow. > > > > > > > I reviewed the documentation part of 0008. I have a few edits attached. > > > > I have just one comment that's not covered in the edits > > > > @@ -4254,8 +4254,8 @@ SELECT * FROM pg_locks pl LEFT JOIN pg_prepared_xacts > > ppx > > <para> > > Anonymous allocations are allocations that have been made > > with <literal>ShmemAlloc()</literal> directly, rather than via > > - <literal>ShmemInitStruct()</literal> or > > - <literal>ShmemInitHash()</literal>. > > + <literal>ShmemRequestStruct()</literal> or > > + <literal>ShmemRequestHash()</literal>. > > </para> > > > > ShmemInitStruct() and ShmemInitHash() are still the functions to > > allocate named structures. If we are going to keep ShmemInitStruct() > > and ShmemInitHash() around for a while, I think it is more accurate to > > mention them in this sentence along with the new functions. > > > > Will continue reviewing the patch tomorrow. > > > > Here's a complete review of 0008 (from version 7). I see you have > already posted v8 which I have not looked at.
I rebased my resizable shared memory structures patch on top of your v8 patch to check if newer APIs are still useful for resizable structures. Attached is the resultant WIP patch. I will rebase and finalize it once these patches are committed. Here are some review comments coming out of that exercise. The patch subtly changes what allocated_size means in ShmemIndexEntry. Without this patch, the next structure started from entry->location + allocated_bytes whereas now the given structure starts at a type aligned address whereas the next structure may start anywhere after size bytes from the type aligned address. I think these patches have got it right (current head the code gets it correct since it uses the same alignment for all the structures.). But I think the comments for allocated_size should make it clear that it's not the size available to the structure, as it used to be. The current comments and the code in HEAD may make one think so. What if the caller changes the ShmemStructDesc, which seems to be the handle we are talking about upthread? Should we make it opaque so that the callers can not play with it? -- Best Wishes, Ashutosh Bapat
resizable_shmem_struct.patch.nocibot
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