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Add a new hint bit on the flags parameter of sqlite3BtreeDelete(). The new

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BTREE_IDXDELETE bit indicates that the call is to delete an index entry 
corresponding to a table row that has already been deleted.

FossilOrigin-Name: ac2cbadd8000947c097da5b00c00090fe58fdcff
This commit is contained in:
drh 2016-01-21 17:06:33 +00:00
parent 9c0c57a4ca
commit e807bdba86
7 changed files with 73 additions and 33 deletions
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23
manifest
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@ -1,5 +1,5 @@
C Improved\scomments\son\sthe\sFORDELETE\shint.\s\sNo\slogic\schanges.
D 2016-01-21T15:55:37.704
C Add\sa\snew\shint\sbit\son\sthe\sflags\sparameter\sof\ssqlite3BtreeDelete().\s\sThe\snew\nBTREE_IDXDELETE\sbit\sindicates\sthat\sthe\scall\sis\sto\sdelete\san\sindex\sentry\s\ncorresponding\sto\sa\stable\srow\sthat\shas\salready\sbeen\sdeleted.
D 2016-01-21T17:06:33.267
F Makefile.in 7be88f5b473891e3a8c07245ed60535fcda4f9ee
F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
F Makefile.msc c5ead4aa22ff6f528c755b07ed1e31184ac5b3d2
@ -288,8 +288,8 @@ F src/auth.c b56c78ebe40a2110fd361379f7e8162d23f92240
F src/backup.c 2869a76c03eb393ee795416e2387005553df72bc
F src/bitvec.c 1a78d450a17c5016710eec900bedfc5729bf9bdf
F src/btmutex.c bc87dd3b062cc26edfe79918de2200ccb8d41e73
F src/btree.c f224ae877fde69d1a9d430f502edaf8502752dbe
F src/btree.h 526137361963e746949ab966a910c7f455ac6b04
F src/btree.c 97cf881292e085ee71faf44f7167b6312965b562
F src/btree.h c5dfbbc59226fa5fcc2b03befa85fe10ef23c1b5
F src/btreeInt.h c18b7d2a3494695133e4e60ee36061d37f45d9a5
F src/build.c 31af80bba31ac159967951ef58f3144cc7db9d70
F src/callback.c 29ae4faba226c7ebb9aee93016b5ce8a8f071261
@ -297,7 +297,7 @@ F src/complete.c addcd8160b081131005d5bc2d34adf20c1c5c92f
F src/ctime.c 60e135af364d777a9ab41c97e5e89cd224da6198
F src/date.c 997651e3ee6c2818fbf7fcdb7156cef9eb3ece20
F src/dbstat.c ffd63fc8ba7541476ced189b95e95d7f2bc63f78
F src/delete.c 00af9f08a15ddc5cba5962d3d3e5bf2d67b2e7da
F src/delete.c f02e46234c5fc86f6c03ae34dc0ba48e93cd5029
F src/expr.c df0d7c3230d59abd679da22ff5ce4cfd0e3a0e63
F src/fault.c 160a0c015b6c2629d3899ed2daf63d75754a32bb
F src/fkey.c e18b3dff7d47c7bcac5ac4fc178a89b9fd322b44
@ -350,7 +350,7 @@ F src/shell.c dcd7a83645ef2a58ee9c6d0ea4714d877d7835c4
F src/sqlite.h.in 214476a62012e578f42133a9a3b4f97a9aa421a3
F src/sqlite3.rc 992c9f5fb8285ae285d6be28240a7e8d3a7f2bad
F src/sqlite3ext.h dfbe62ffd95b99afe2140d8c35b180d11924072d
F src/sqliteInt.h 0403328581127bc8ad2f9cc7af2c3bb23d5316da
F src/sqliteInt.h 46e0bac7a3cdab96e8b5afd1436accc25d2c3d6a
F src/sqliteLimit.h 216557999cb45f2e3578ed53ebefe228d779cb46
F src/status.c 70912d7be68e9e2dbc4010c93d344af61d4c59ba
F src/table.c 51b46b2a62d1b3a959633d593b89bab5e2c9155e
@ -410,7 +410,7 @@ F src/update.c 17332f9fe818cbc0444c36a811800af8498af4c3
F src/utf.c 32d7f82aa921322f3e1c956f4b58f019ebd2c6b3
F src/util.c e802e8e311a0d6c48cd1b3e89db164f6f0248d70
F src/vacuum.c 2ddd5cad2a7b9cef7f9e431b8c7771634c6b1701
F src/vdbe.c b90d9d38e5e0260c2eafa3cb4c2274d8ea94da27
F src/vdbe.c e21a506d17a7397cba16c162d8c9c96e9769c68e
F src/vdbe.h 7a733ea8aac1b77305a67698e784fa3484ee3337
F src/vdbeInt.h 42eefa4f9e7432b9968d321b44e48821ec13b189
F src/vdbeapi.c ffae8f5af4570fbd548504e815e9fb7227f0822e
@ -1419,7 +1419,10 @@ F tool/vdbe_profile.tcl 246d0da094856d72d2c12efec03250d71639d19f
F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
F tool/warnings.sh 48bd54594752d5be3337f12c72f28d2080cb630b
F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
P f60f025027ab3acdbc97701f81ff9c11c8463022
R 58c662ebb54c7087fe70ba0b9b653627
P a3cec529f0238e4ca1196fec420f2de80d28db78
R 76198b2176fddd32b1fb9b7a5f18b4c8
T *branch * btree-fordelete-flag
T *sym-btree-fordelete-flag *
T -sym-trunk *
U drh
Z 656e64b9ebb4ed29ac85ca9fad2e65b0
Z c987d8ca8053309611f1f75e6c6acde5

2
manifest.uuid
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@ -1 +1 @@
a3cec529f0238e4ca1196fec420f2de80d28db78
ac2cbadd8000947c097da5b00c00090fe58fdcff

41
src/btree.c
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@ -4049,13 +4049,13 @@ int sqlite3BtreeSavepoint(Btree *p, int op, int iSavepoint){
** on the database already. If a write-cursor is requested, then
** the caller is assumed to have an open write transaction.
**
** If wrFlag==0, then the cursor can only be used for reading.
** If wrFlag==1, then the cursor can be used for reading or for
** writing if other conditions for writing are also met. These
** are the conditions that must be met in order for writing to
** be allowed:
** If the BTREE_WRCSR bit of wrFlag is clear, then the cursor can only
** be used for reading. If the BTREE_WRCSR bit is set, then the cursor
** can be used for reading or for writing if other conditions for writing
** are also met. These are the conditions that must be met in order
** for writing to be allowed:
**
** 1: The cursor must have been opened with wrFlag==1
** 1: The cursor must have been opened with wrFlag containing BTREE_WRCSR
**
** 2: Other database connections that share the same pager cache
** but which are not in the READ_UNCOMMITTED state may not have
@ -4067,6 +4067,16 @@ int sqlite3BtreeSavepoint(Btree *p, int op, int iSavepoint){
**
** 4: There must be an active transaction.
**
** The BTREE_FORDELETE bit of wrFlag may optionally be set if BTREE_WRCSR
** is set. If FORDELETE is set, that is a hint to the implementation that
** this cursor will only be used to seek to and delete entries of an index
** as part of a larger DELETE statement. The FORDELETE hint is not used by
** this implementation. But in a hypothetical alternative storage engine
** in which index entries are automatically deleted when corresponding table
** rows are deleted, the FORDELETE flag is a hint that all SEEK and DELETE
** operations on this cursor can be no-ops and all READ operations can
** return a null row (2-bytes: 0x01 0x00).
**
** No checking is done to make sure that page iTable really is the
** root page of a b-tree. If it is not, then the cursor acquired
** will not work correctly.
@ -8082,13 +8092,18 @@ end_insert:
/*
** Delete the entry that the cursor is pointing to.
**
** If the second parameter is zero, then the cursor is left pointing at an
** arbitrary location after the delete. If it is non-zero, then the cursor
** is left in a state such that the next call to BtreeNext() or BtreePrev()
** moves it to the same row as it would if the call to BtreeDelete() had
** been omitted.
** If the BTREE_SAVEPOSITION bit of the flags parameter is zero, then
** the cursor is left pointing at an arbitrary location after the delete.
** But if that bit is set, then the cursor is left in a state such that
** the next call to BtreeNext() or BtreePrev() moves it to the same row
** as it would have been on if the call to BtreeDelete() had been omitted.
**
** The BTREE_IDXDELETE bit of flags indicates that this is a delete of
** an index entry where the corresponding table row has already been deleted.
** The BTREE_IDXDELETE bit is a hint that is not used by this implementation,
** but which might be used by alternative storage engines.
*/
int sqlite3BtreeDelete(BtCursor *pCur, int bPreserve){
int sqlite3BtreeDelete(BtCursor *pCur, u8 flags){
Btree *p = pCur->pBtree;
BtShared *pBt = p->pBt;
int rc; /* Return code */
@ -8098,6 +8113,7 @@ int sqlite3BtreeDelete(BtCursor *pCur, int bPreserve){
int iCellDepth; /* Depth of node containing pCell */
u16 szCell; /* Size of the cell being deleted */
int bSkipnext = 0; /* Leaf cursor in SKIPNEXT state */
u8 bPreserve = flags & BTREE_SAVEPOSITION; /* Keep cursor valid */
assert( cursorOwnsBtShared(pCur) );
assert( pBt->inTransaction==TRANS_WRITE );
@ -8107,6 +8123,7 @@ int sqlite3BtreeDelete(BtCursor *pCur, int bPreserve){
assert( !hasReadConflicts(p, pCur->pgnoRoot) );
assert( pCur->aiIdx[pCur->iPage]<pCur->apPage[pCur->iPage]->nCell );
assert( pCur->eState==CURSOR_VALID );
assert( (flags & ~(BTREE_SAVEPOSITION | BTREE_IDXDELETE))==0 );
iCellDepth = pCur->iPage;
iCellIdx = pCur->aiIdx[iCellDepth];

7
src/btree.h
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@ -245,7 +245,12 @@ int sqlite3BtreeMovetoUnpacked(
);
int sqlite3BtreeCursorHasMoved(BtCursor*);
int sqlite3BtreeCursorRestore(BtCursor*, int*);
int sqlite3BtreeDelete(BtCursor*, int);
int sqlite3BtreeDelete(BtCursor*, u8 flags);
/* Allowed flags for the 2nd argument to sqlite3BtreeDelete() */
#define BTREE_SAVEPOSITION 0x02 /* Leave cursor pointing at NEXT or PREV */
#define BTREE_IDXDELETE 0x04 /* this is index, table row already deleted */
int sqlite3BtreeInsert(BtCursor*, const void *pKey, i64 nKey,
const void *pData, int nData,
int nZero, int bias, int seekResult);

5
src/delete.c
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@ -718,6 +718,7 @@ void sqlite3GenerateRowDelete(
** a view (in which case the only effect of the DELETE statement is to
** fire the INSTEAD OF triggers). */
if( pTab->pSelect==0 ){
u8 p5 = 0;
sqlite3GenerateRowIndexDelete(pParse, pTab, iDataCur, iIdxCur,0,iIdxNoSeek);
sqlite3VdbeAddOp2(v, OP_Delete, iDataCur, (count?OPFLAG_NCHANGE:0));
if( count ){
@ -725,8 +726,10 @@ void sqlite3GenerateRowDelete(
}
if( iIdxNoSeek>=0 ){
sqlite3VdbeAddOp1(v, OP_Delete, iIdxNoSeek);
if( eMode!=ONEPASS_OFF ) p5 = OPFLAG_IDXDELETE;
}
sqlite3VdbeChangeP5(v, eMode==ONEPASS_MULTI);
if( eMode==ONEPASS_MULTI ) p5 |= OPFLAG_SAVEPOSITION;
sqlite3VdbeChangeP5(v, p5);
}
/* Do any ON CASCADE, SET NULL or SET DEFAULT operations required to

5
src/sqliteInt.h
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@ -2847,7 +2847,8 @@ struct AuthContext {
/*
** Bitfield flags for P5 value in various opcodes.
*/
#define OPFLAG_NCHANGE 0x01 /* Set to update db->nChange */
#define OPFLAG_NCHANGE 0x01 /* OP_Insert: Set to update db->nChange */
/* Also used in P2 (not P5) of OP_Delete */
#define OPFLAG_EPHEM 0x01 /* OP_Column: Ephemeral output is ok */
#define OPFLAG_LASTROWID 0x02 /* Set to update db->lastRowid */
#define OPFLAG_ISUPDATE 0x04 /* This OP_Insert is an sql UPDATE */
@ -2860,6 +2861,8 @@ struct AuthContext {
#define OPFLAG_FORDELETE 0x08 /* OP_Open should use BTREE_FORDELETE */
#define OPFLAG_P2ISREG 0x10 /* P2 to OP_Open** is a register number */
#define OPFLAG_PERMUTE 0x01 /* OP_Compare: use the permutation */
#define OPFLAG_SAVEPOSITION 0x02 /* OP_Delete: keep cursor position */
#define OPFLAG_IDXDELETE 0x04 /* OP_Delete: index in a DELETE op */
/*
* Each trigger present in the database schema is stored as an instance of

23
src/vdbe.c
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@ -4341,14 +4341,20 @@ case OP_InsertInt: {
**
** Delete the record at which the P1 cursor is currently pointing.
**
** If the P5 parameter is non-zero, the cursor will be left pointing at
** either the next or the previous record in the table. If it is left
** pointing at the next record, then the next Next instruction will be a
** no-op. As a result, in this case it is OK to delete a record from within a
** Next loop. If P5 is zero, then the cursor is left in an undefined state.
** If the OPFLAG_SAVEPOSITION bit of the P5 parameter is set, then
** the cursor will be left pointing at either the next or the previous
** record in the table. If it is left pointing at the next record, then
** the next Next instruction will be a no-op. As a result, in this case
** it is ok to delete a record from within a Next loop. If
** OPFLAG_SAVEPOSITION bit of P5 is clear, then the cursor will be
** left in an undefined state.
**
** If the OPFLAG_NCHANGE flag of P2 is set, then the row change count is
** incremented (otherwise not).
** If the OPFLAG_IDXDELETE bit is set on P5, that indicates that this
** delete is on an index cursor where the corresponding table row has
** already been deleted.
**
** If the OPFLAG_NCHANGE flag of P2 (NB: P2 not P5) is set, then the row
** change count is incremented (otherwise not).
**
** P1 must not be pseudo-table. It has to be a real table with
** multiple rows.
@ -4385,6 +4391,9 @@ case OP_Delete: {
}
#endif
assert( (pOp->p5 & ~(OPFLAG_SAVEPOSITION|OPFLAG_IDXDELETE))==0 );
assert( OPFLAG_SAVEPOSITION==BTREE_SAVEPOSITION );
assert( OPFLAG_IDXDELETE==BTREE_IDXDELETE );
rc = sqlite3BtreeDelete(pC->uc.pCursor, pOp->p5);
pC->cacheStatus = CACHE_STALE;