Re: Speed up Clog Access by increasing CLOG buffers

On Wed, Sep 14, 2016 at 8:59 PM, Robert Haas <robertmhaas(at)gmail(dot)com> wrote:
> Sure, but you're testing at *really* high client counts here. Almost
> nobody is going to benefit from a 5% improvement at 256 clients.

I agree with your point, but here we need to consider one more thing,
that on head we are gaining ~30% with both the approaches.

So for comparing these two patches we can consider..

A. Other workloads (one can be as below)
-> Load on CLogControlLock at commit (exclusive mode) + Load on
CLogControlLock at Transaction status (shared mode).
I think we can mix (savepoint + updates)

B. Simplicity of the patch (if both are performing almost equal in all
practical scenarios).

C. Bases on algorithm whichever seems winner.

I will try to test these patches with other workloads...

> You
> need to test 64 clients and 32 clients and 16 clients and 8 clients
> and see what happens there. Those cases are a lot more likely than
> these stratospheric client counts.

I tested with 64 clients as well..
1. On head we are gaining ~15% with both the patches.
2. But group lock vs granular lock is almost same.

--
Regards,
Dilip Kumar
EnterpriseDB: http://www.enterprisedb.com