Re: [CFReview] Red-Black Tree

From: Teodor Sigaev <teodor(at)sigaev(dot)ru>
To: Robert Haas <robertmhaas(at)gmail(dot)com>
Cc: Mark Cave-Ayland <mark(dot)cave-ayland(at)siriusit(dot)co(dot)uk>, Pgsql Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: [CFReview] Red-Black Tree
Date: 2010-02-09 14:21:10
Message-ID: 4B716F56.4060205@sigaev.ru
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>> Good idea, implemented.
>
> Hmm. I think your implementation is prone to overflow in two places -
> both when computing step, and also when stepping through the array.

Pls, point me, I don't see that
! step |= (step >> 1);
! step |= (step >> 2);
! step |= (step >> 4);
! step |= (step >> 8);
! step |= (step >> 16);
! step ++;
! step >>= 1;
!
! while(step > 0) {
! int i;

! for (i = step-1; i < nentry; i += 2 * step)
! ginInsertEntry(accum, heapptr, attnum, entries[i]);

! step >>= 1; /* /2 */
! }

> Proposed revision attached, with also some rewriting of the comment
> for that function.

make check fails with your patch:

#3 0x083d2b50 in ExceptionalCondition (conditionName=Could not find the frame
base for "ExceptionalCondition".
) at assert.c:57
#4 0x081086b6 in ginAppendData (old=0x287f2030, new=0x287f2044, arg=0xbfbfd5e4)
at ginbulk.c:48
#5 0x083f5632 in rb_insert (rb=0x2acfe610, data=0x287f2044) at rbtree.c:359
#6 0x08108968 in ginInsertEntry (accum=0xbfbfd5e4, heapptr=0x28711af4,
attnum=1, entry=2139062143) at ginbulk.c:135
#7 0x08108ad9 in ginInsertRecordBA (accum=0xbfbfd5e4, heapptr=0x28711af4,
attnum=1, entries=0x2ac77068, nentry=6) at ginbulk.c:202
--
Teodor Sigaev E-mail: teodor(at)sigaev(dot)ru
WWW: http://www.sigaev.ru/

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