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Move TupleTableSlots boolean member into one flag variable.

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There's several reasons for this change:
1) It reduces the total size of TupleTableSlot / reduces alignment
   padding, making the commonly accessed members fit into a single
   cacheline (but we currently do not force proper alignment, so
   that's not yet guaranteed to be helpful)
2) Combining the booleans into a flag allows to combine read/writes
   from memory.
3) With the upcoming slot abstraction changes, it allows to have core
   and extended flags, in a memory efficient way.

Author: Ashutosh Bapat and Andres Freund
Discussion: https://postgr.es/m/20180220224318.gw4oe5jadhpmcdnm@alap3.anarazel.de
This commit is contained in:
Andres Freund
2018-10-15 15:24:33 -07:00
parent 9d906f1119
commit c5257345ef
8 changed files with 116 additions and 72 deletions
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7
src/backend/access/common/heaptuple.c
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@ -1391,7 +1391,7 @@ slot_deform_tuple(TupleTableSlot *slot, int natts)
{
/* Restore state from previous execution */
off = slot->tts_off;
slow = slot->tts_slow;
slow = TTS_SLOW(slot);
}
tp = (char *) tup + tup->t_hoff;
@ -1452,7 +1452,10 @@ slot_deform_tuple(TupleTableSlot *slot, int natts)
*/
slot->tts_nvalid = attnum;
slot->tts_off = off;
slot->tts_slow = slow;
if (slow)
slot->tts_flags |= TTS_FLAG_SLOW;
else
slot->tts_flags &= ~TTS_FLAG_SLOW;
}
/*