Horton

Re: On partitioning

Jim Nasby <jim.nasby@bluetreble.com>

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From: Jim Nasby <Jim.Nasby@BlueTreble.com>
To: Robert Haas <robertmhaas@gmail.com>, Amit Kapila <amit.kapila16@gmail.com>
Cc: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>, Andres Freund <andres@2ndquadrant.com>, Alvaro Herrera <alvherre@2ndquadrant.com>, Bruce Momjian <bruce@momjian.us>, Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2014-12-08T22:05:39Z
Lists: pgsql-hackers 
On 12/8/14, 1:05 PM, Robert Haas wrote:
> Besides, I haven't really seen anyone propose something that sounds
> like a credible alternative.  If we could make partition objects
> things that the storage layer needs to know about but the query
> planner doesn't need to understand, that'd be maybe worth considering.
> But I don't see any way that that's remotely feasible.  There are lots
> of places that we assume that a heap consists of blocks number 0 up
> through N: CTID pointers, index-to-heap pointers, nodeSeqScan, bits
> and pieces of the way index vacuuming is handled, which in turn bleeds
> into Hot Standby.  You can't just decide that now block numbers are
> going to be replaced by some more complex structure, or even that
> they're now going to be nonlinear, without breaking a huge amount of
> stuff.

Agreed, but it's possible to keep a block/CTID interface while doing something different on the disk.

If you think about it, partitioning is really a hack anyway. It clutters up your logical set implementation with a bunch of physical details. What most people really want when they implement partitioning is simply data locality.
-- 
Jim Nasby, Data Architect, Blue Treble Consulting
Data in Trouble? Get it in Treble! http://BlueTreble.com