Re: GiST concurrency

> If the method needs a truly global LSN, then it is broken --- the only
> way you could have such a value and have it stay good long enough to do
> anything with it is to block all other backends from inserting any new
> WAL records. Which is the very antithesis of concurrency.
>
Global LSN needs to recognize page split produced another process by search
algorithm, no more.

> I think you probably misunderstood the paper. It looks to me like the
> proposal in the paper is to use the LSN assigned to the WAL record that
> represents a page split operation. Which you get from the XLogInsert
> --- there's no need for an extra call.

You partially right, I don't read it with care chaper 10.1 last paragraph :(
<quotation>
To alleviate the traffic on this high-frequency counter (LSN - teodor),
descending operations can memorize the node's LSN instead.
</quotation>

So, value of global LSN isn't needed.

--
Teodor Sigaev E-mail: teodor(at)sigaev(dot)ru
WWW: http://www.sigaev.ru/