Horton

Re: Patch: Write Amplification Reduction Method (WARM)

Pavan Deolasee <pavan.deolasee@gmail.com>

View thread View on postgr.es
From: Pavan Deolasee <pavan.deolasee@gmail.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Mithun Cy <mithun.cy@enterprisedb.com>, Robert Haas <robertmhaas@gmail.com>, Alvaro Herrera <alvherre@2ndquadrant.com>, Bruce Momjian <bruce@momjian.us>, Jaime Casanova <jaime.casanova@2ndquadrant.com>, Haribabu Kommi <kommi.haribabu@gmail.com>, Tomas Vondra <tomas.vondra@2ndquadrant.com>, pgsql-hackers <pgsql-hackers@postgresql.org>
Date: 2017-03-23T11:34:01Z
Lists: pgsql-hackers 
On Thu, Mar 23, 2017 at 4:08 PM, Pavan Deolasee <pavan.deolasee@gmail.com>
wrote:

>
>
> On Thu, Mar 23, 2017 at 3:02 PM, Amit Kapila <amit.kapila16@gmail.com>
> wrote:
>
>>
>>
>> That sounds like you are dodging the actual problem.  I mean you can
>> put that same PageIsFull() check in master code as well and then you
>> will most probably again see the same regression.
>
>
> Well I don't see it that way. There was a specific concern about a
> specific workload that WARM might regress. I think this change addresses
> that. Sure if you pick that one piece, put it in master first and then
> compare against rest of the WARM code, you will see a regression.
>

BTW the PageIsFull() check may not help as much in master as it does with
WARM. In master we anyways bail out early after couple of column checks. In
master it may help to reduce the 10% drop that we see while updating last
index column, but if we compare master and WARM with the patch applied,
regression should be quite nominal.

Thanks,
Pavan

-- 
 Pavan Deolasee                   http://www.2ndQuadrant.com/
 PostgreSQL Development, 24x7 Support, Training & Services

Commits

  1. Implement SortSupport for macaddr data type

  2. Simplify check of modified attributes in heap_update

  3. Remove direct uses of ItemPointer.{ip_blkid,ip_posid}

  4. Fix CatalogTupleInsert/Update abstraction for case of shared indstate.

  5. Provide CatalogTupleDelete() as a wrapper around simple_heap_delete().

  6. Band-aid fix for incorrect use of view options as StdRdOptions.

  7. Update visibility map in the second phase of vacuum.

  8. Avoid having two copies of the HOT-chain search logic.

  9. Postgres95 1.01 Distribution - Virgin Sources