Horton

Re: Patch: Write Amplification Reduction Method (WARM)

Robert Haas <robertmhaas@gmail.com>

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From: Robert Haas <robertmhaas@gmail.com>
To: Amit Kapila <amit.kapila16@gmail.com>
Cc: Pavan Deolasee <pavan.deolasee@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: 2017-03-30T14:25:26Z
Lists: pgsql-hackers 
On Thu, Mar 30, 2017 at 10:08 AM, Amit Kapila <amit.kapila16@gmail.com> wrote:
> I think we should not consider doing compression and decompression as
> free at this point in code, because we hold a buffer lock during
> recheck. Buffer locks are meant for short-term locks (it is even
> mentioned in storage/buffer/README), doing all the
> compression/decompression/detoast stuff under these locks doesn't
> sound advisable to me.  It can block many concurrent operations.

Compression and decompression might cause performance problems, but
try to access the TOAST table would be fatal; that probably would have
deadlock hazards among other problems.

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

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