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Overview
| Comment: | Improvements to the wording of some comments. Reinstate an assert() that is only true for non-corrupt database files by adding an "|| CORRUPT_DB" term. |
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| Downloads: | Tarball | ZIP archive |
| Timelines: | family | ancestors | descendants | both | trunk |
| Files: | files | file ages | folders |
| SHA1: |
67adb44838f98805f86aecca634d9a3b |
| User & Date: | drh 2014-10-30 23:14:56.756 |
Context
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2014-10-31
| ||
| 00:05 | In the balance_nonroot() routine, protect the values in aPgno[] array from change during the page sort, so that aPgno[] can be used to avoid unnecessary pointer-map updates for auto_vacuum databases. (check-in: 69c3924fe8 user: drh tags: trunk) | |
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2014-10-30
| ||
| 23:14 | Improvements to the wording of some comments. Reinstate an assert() that is only true for non-corrupt database files by adding an "|| CORRUPT_DB" term. (check-in: 67adb44838 user: drh tags: trunk) | |
| 20:48 | Tweaks to comments in btree.c. Minor code changes to enhance testability. (check-in: c7d9aa3a1c user: drh tags: trunk) | |
Changes
Changes to src/btree.c.
| ︙ | ︙ | |||
6522 6523 6524 6525 6526 6527 6528 | int szScratch; /* Size of scratch memory requested */ MemPage *apOld[NB]; /* pPage and up to two siblings */ MemPage *apNew[NB+2]; /* pPage and up to NB siblings after balancing */ u8 *pRight; /* Location in parent of right-sibling pointer */ u8 *apDiv[NB-1]; /* Divider cells in pParent */ int cntNew[NB+2]; /* Index in aCell[] of cell after i-th page */ int cntOld[NB+2]; /* Old index in aCell[] after i-th page */ | | | 6522 6523 6524 6525 6526 6527 6528 6529 6530 6531 6532 6533 6534 6535 6536 | int szScratch; /* Size of scratch memory requested */ MemPage *apOld[NB]; /* pPage and up to two siblings */ MemPage *apNew[NB+2]; /* pPage and up to NB siblings after balancing */ u8 *pRight; /* Location in parent of right-sibling pointer */ u8 *apDiv[NB-1]; /* Divider cells in pParent */ int cntNew[NB+2]; /* Index in aCell[] of cell after i-th page */ int cntOld[NB+2]; /* Old index in aCell[] after i-th page */ int szNew[NB+2]; /* Combined size of cells placed on i-th page */ u8 **apCell = 0; /* All cells begin balanced */ u16 *szCell; /* Local size of all cells in apCell[] */ u8 *aSpace1; /* Space for copies of dividers cells */ Pgno pgno; /* Temp var to store a page number in */ u8 abDone[NB+2]; /* True after i'th new page is populated */ Pgno aPgno[NB+2]; /* Page numbers of new pages before shuffling */ u16 aPgFlags[NB+2]; /* flags field of new pages before shuffling */ |
| ︙ | ︙ | |||
6761 6762 6763 6764 6765 6766 6767 | } szNew[k] = subtotal; cntNew[k] = nCell; k++; /* ** The packing computed by the previous block is biased toward the siblings | | | > | | 6761 6762 6763 6764 6765 6766 6767 6768 6769 6770 6771 6772 6773 6774 6775 6776 6777 6778 |
}
szNew[k] = subtotal;
cntNew[k] = nCell;
k++;
/*
** The packing computed by the previous block is biased toward the siblings
** on the left side (siblings with smaller keys). The left siblings are
** always nearly full, while the right-most sibling might be nearly empty.
** The next block of code attempts to adjust the packing of siblings to
** get a better balance.
**
** This adjustment is more than an optimization. The packing above might
** be so out of balance as to be illegal. For example, the right-most
** sibling might be completely empty. This adjustment is not optional.
*/
for(i=k-1; i>0; i--){
int szRight = szNew[i]; /* Size of sibling on the right */
|
| ︙ | ︙ | |||
6792 6793 6794 6795 6796 6797 6798 |
r = cntNew[i-1] - 1;
d = r + 1 - leafData;
}
szNew[i] = szRight;
szNew[i-1] = szLeft;
}
| > > | | | | < < < < | < < | 6793 6794 6795 6796 6797 6798 6799 6800 6801 6802 6803 6804 6805 6806 6807 6808 6809 6810 6811 6812 6813 6814 |
r = cntNew[i-1] - 1;
d = r + 1 - leafData;
}
szNew[i] = szRight;
szNew[i-1] = szLeft;
}
/* Sanity check: For a non-corrupt database file one of the follwing
** must be true:
** (1) We found one or more cells (cntNew[0])>0), or
** (2) pPage is a virtual root page. A virtual root page is when
** the real root page is page 1 and we are the only child of
** that page.
*/
assert( cntNew[0]>0 || (pParent->pgno==1 && pParent->nCell==0) || CORRUPT_DB);
TRACE(("BALANCE: old: %d(nc=%d) %d(nc=%d) %d(nc=%d)\n",
apOld[0]->pgno, apOld[0]->nCell,
nOld>=2 ? apOld[1]->pgno : 0, nOld>=2 ? apOld[1]->nCell : 0,
nOld>=3 ? apOld[2]->pgno : 0, nOld>=3 ? apOld[2]->nCell : 0
));
/*
|
| ︙ | ︙ |