Horton

Re: TupleTableSlot abstraction

Amit Khandekar <amitdkhan.pg@gmail.com>

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From: Amit Khandekar <amitdkhan.pg@gmail.com>
To: Andres Freund <andres@anarazel.de>
Cc: Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>, pgsql-hackers <pgsql-hackers@postgresql.org>, Robert Haas <robertmhaas@gmail.com>, Haribabu Kommi <kommi.haribabu@gmail.com>, Alvaro Herrera <alvherre@2ndquadrant.com>, Amit Kapila <amit.kapila16@gmail.com>
Date: 2018-10-11T05:03:22Z
Lists: pgsql-hackers 
On Wed, 26 Sep 2018 at 05:15, Andres Freund <andres@anarazel.de> wrote:
>
> Hi,
>
> On 2018-09-04 18:35:34 +0530, Amit Khandekar wrote:
> > Subject: [PATCH 05/14] Use tts_flags instead of previous bool members
> >
> > Pack the boolean members in TupleTableSlot into a 16 bit tts_flags.
> > This reduces the size of TupleTableSlot since each bool member takes
> > at least a byte on the platforms where bool is defined as a char.
> >
> > Ashutosh Bapat and Andres Freund
>
> > +
> > +/* true = slot is empty */
> > +#define                      TTS_ISEMPTY                     (1 << 1)
> > +#define IS_TTS_EMPTY(slot)   ((slot)->tts_flags & TTS_ISEMPTY)
> > +#define SET_TTS_EMPTY(slot) ((slot)->tts_flags |= TTS_ISEMPTY)
> > +#define RESET_TTS_EMPTY(slot) ((slot)->tts_flags &= ~TTS_ISEMPTY)
>
> The flag stuff is the right way, but I'm a bit dubious about the
> accessor functions.  I can see open-coding the accesses, using the
> macros, or potentially going towards using bitfields.
>
> Any comments?

I like this abstraction using macros, since this will allow us to
conveniently change the way this information is stored inside the
slot. I think for this same reason we have defined macros
(HeapTupleIsHotUpdated, etc) for each bit of heaptuple infomask.

-- 
Thanks,
-Amit Khandekar
EnterpriseDB Corporation
The Postgres Database Company

Commits

  1. Fix memory leak when inserting tuple at relation creation for CTAS

  2. Build HashState's hashkeys expression with the correct parent.

  3. Move TupleTableSlots boolean member into one flag variable.

  4. Move generic slot support functions from heaptuple.c into execTuples.c.

  5. Remove absolete function TupleDescGetSlot().

  6. Remove function list from prologue of execTuples.c.

  7. Split ExecStoreTuple into ExecStoreHeapTuple and ExecStoreBufferHeapTuple.

  8. Change TupleTableSlot->tts_nvalid to type AttrNumber.

  9. Deduplicate code between slot_getallattrs() and slot_getsomeattrs().

  10. Mention ownership requirements for REFRESH MATERIALIZED VIEW in docs

  11. Spell "partitionwise" consistently.

  12. Fix WHERE CURRENT OF when the referenced cursor uses an index-only scan.