Re: Zedstore - compressed in-core columnar storage

Hi Ashwin,

I tried playing around with the zedstore code a bit today and there
are couple questions that came into my mind.

1) Can zedstore tables be vacuumed? If yes, does VACUUM on zedstore
table set the VM bits associated with it.

2) Is there a chance that IndexOnlyScan would ever be required for
zedstore tables considering the design approach taken for it?

Further, I tried creating a zedstore table with btree index on one of
it's column and loaded around 50 lacs record into the table. When the
indexed column was scanned (with enable_seqscan flag set to off), it
went for IndexOnlyScan and that took around 15-20 times more than it
would take for IndexOnly Scan on heap table just because IndexOnlyScan
in zedstore always goes to heap as the visibility check fails.
However, the seqscan on zedstore table is quite faster than seqscan on
heap table because the time taken for I/O is quite less in case for
zedstore.

--
With Regards,
Ashutosh Sharma
EnterpriseDB:http://www.enterprisedb.com

On Tue, Jul 2, 2019 at 12:45 AM Ashwin Agrawal <aagrawal(at)pivotal(dot)io> wrote:
>
> On Thu, May 30, 2019 at 8:07 AM DEV_OPS <devops(at)ww-it(dot)cn> wrote:
>>
>>
>> it's really cool and very good progress,
>>
>> I'm interesting if SIDM/JIT will be supported
>
>
> That's something outside of Zedstore work directly at least now. The intent is to work with current executor code or enhance it only wherever needed. If current executor code supports something that would work for Zedstore. But any other enhancements to executor will be separate undertaking.