Re: [HACKERS] POC: Sharing record typmods between backends

On Tue, May 30, 2017 at 2:45 AM, Dilip Kumar <dilipbalaut@gmail.com> wrote:
> On Tue, May 30, 2017 at 1:09 AM, Thomas Munro
> <thomas.munro@enterprisedb.com> wrote:
>>> * Perhaps simplehash + an LWLock would be better than dht, but I
>>> haven't looked into that.  Can it be convinced to work in DSA memory
>>> and to grow on demand?
>
> Simplehash provides an option to provide your own allocator function
> to it. So in the allocator function, you can allocate memory from DSA.
> After it reaches some threshold it expands the size (double) and it
> will again call the allocator function to allocate the bigger memory.
> You can refer pagetable_allocate in tidbitmap.c.

That only allows the pagetable to be shared, not the hash table itself.

-- 
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company