DBD-SQLeet
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** the column is not changed by the UPDATE statement, then the xColumn
** method can optionally return without setting a result, without calling
** any of the [sqlite3_result_int|sqlite3_result_xxxxx() interfaces].
** In that case, [sqlite3_value_nochange(X)] will return true for the
** same column in the [xUpdate] method.
*/
SQLITE_API int sqlite3_vtab_nochange(sqlite3_context*);
/*
** CAPI3REF: Determine The Collation For a Virtual Table Constraint
**
** This function may only be called from within a call to the [xBestIndex]
** method of a [virtual table].
**
** The first argument must be the sqlite3_index_info object that is the
** first parameter to the xBestIndex() method. The second argument must be
** an index into the aConstraint[] array belonging to the sqlite3_index_info
** structure passed to xBestIndex. This function returns a pointer to a buffer
** containing the name of the collation sequence for the corresponding
** constraint.
*/
SQLITE_API SQLITE_EXPERIMENTAL const char *sqlite3_vtab_collation(sqlite3_index_info*,int);
/*
** CAPI3REF: Conflict resolution modes
** KEYWORDS: {conflict resolution mode}
**
** These constants are returned by [sqlite3_vtab_on_conflict()] to
** inform a [virtual table] implementation what the [ON CONFLICT] mode
** is for the SQL statement being evaluated.
**
** Note that the [SQLITE_IGNORE] constant is also used as a potential
** return value from the [sqlite3_set_authorizer()] callback and that
** [SQLITE_ABORT] is also a [result code].
*/
#define SQLITE_ROLLBACK 1
/* #define SQLITE_IGNORE 2 // Also used by sqlite3_authorizer() callback */
#define SQLITE_FAIL 3
/* #define SQLITE_ABORT 4 // Also an error code */
#define SQLITE_REPLACE 5
/*
** CAPI3REF: Prepared Statement Scan Status Opcodes
** KEYWORDS: {scanstatus options}
**
** The following constants can be used for the T parameter to the
** [sqlite3_stmt_scanstatus(S,X,T,V)] interface. Each constant designates a
** different metric for sqlite3_stmt_scanstatus() to return.
**
** When the value returned to V is a string, space to hold that string is
** managed by the prepared statement S and will be automatically freed when
** S is finalized.
**
** <dl>
** [[SQLITE_SCANSTAT_NLOOP]] <dt>SQLITE_SCANSTAT_NLOOP</dt>
** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be
** set to the total number of times that the X-th loop has run.</dd>
**
** [[SQLITE_SCANSTAT_NVISIT]] <dt>SQLITE_SCANSTAT_NVISIT</dt>
** <dd>^The [sqlite3_int64] variable pointed to by the T parameter will be set
** to the total number of rows examined by all iterations of the X-th loop.</dd>
**
** [[SQLITE_SCANSTAT_EST]] <dt>SQLITE_SCANSTAT_EST</dt>
** <dd>^The "double" variable pointed to by the T parameter will be set to the
** query planner's estimate for the average number of rows output from each
** iteration of the X-th loop. If the query planner's estimates was accurate,
** then this value will approximate the quotient NVISIT/NLOOP and the
** product of this value for all prior loops with the same SELECTID will
** be the NLOOP value for the current loop.
**
** [[SQLITE_SCANSTAT_NAME]] <dt>SQLITE_SCANSTAT_NAME</dt>
** <dd>^The "const char *" variable pointed to by the T parameter will be set
** to a zero-terminated UTF-8 string containing the name of the index or table
** used for the X-th loop.
**
** [[SQLITE_SCANSTAT_EXPLAIN]] <dt>SQLITE_SCANSTAT_EXPLAIN</dt>
** <dd>^The "const char *" variable pointed to by the T parameter will be set
** to a zero-terminated UTF-8 string containing the [EXPLAIN QUERY PLAN]
** description for the X-th loop.
**
** [[SQLITE_SCANSTAT_SELECTID]] <dt>SQLITE_SCANSTAT_SELECT</dt>
** <dd>^The "int" variable pointed to by the T parameter will be set to the
** "select-id" for the X-th loop. The select-id identifies which query or
** subquery the loop is part of. The main query has a select-id of zero.
** The select-id is the same value as is output in the first column
** of an [EXPLAIN QUERY PLAN] query.
** </dl>
*/
#define SQLITE_SCANSTAT_NLOOP 0
#define SQLITE_SCANSTAT_NVISIT 1
#define SQLITE_SCANSTAT_EST 2
#define SQLITE_SCANSTAT_NAME 3
#define SQLITE_SCANSTAT_EXPLAIN 4
#define SQLITE_SCANSTAT_SELECTID 5
/*
** CAPI3REF: Prepared Statement Scan Status
** METHOD: sqlite3_stmt
**
** This interface returns information about the predicted and measured
** performance for pStmt. Advanced applications can use this
** interface to compare the predicted and the measured performance and
** issue warnings and/or rerun [ANALYZE] if discrepancies are found.
**
** Since this interface is expected to be rarely used, it is only
** available if SQLite is compiled using the [SQLITE_ENABLE_STMT_SCANSTATUS]
** compile-time option.
**
** The "iScanStatusOp" parameter determines which status information to return.
** The "iScanStatusOp" must be one of the [scanstatus options] or the behavior
** of this interface is undefined.
** ^The requested measurement is written into a variable pointed to by
** the "pOut" parameter.
** Parameter "idx" identifies the specific loop to retrieve statistics for.
** Loops are numbered starting from zero. ^If idx is out of range - less than
** zero or greater than or equal to the total number of loops used to implement
** the statement - a non-zero value is returned and the variable that pOut
** points to is unchanged.
**
** ^Statistics might not be available for all loops in all statements. ^In cases
** where there exist loops with no available statistics, this function behaves
# define DbMaskNonZero(M) (M)!=0
#endif
/*
** An SQL parser context. A copy of this structure is passed through
** the parser and down into all the parser action routine in order to
** carry around information that is global to the entire parse.
**
** The structure is divided into two parts. When the parser and code
** generate call themselves recursively, the first part of the structure
** is constant but the second part is reset at the beginning and end of
** each recursion.
**
** The nTableLock and aTableLock variables are only used if the shared-cache
** feature is enabled (if sqlite3Tsd()->useSharedData is true). They are
** used to store the set of table-locks required by the statement being
** compiled. Function sqlite3TableLock() is used to add entries to the
** list.
*/
struct Parse {
sqlite3 *db; /* The main database structure */
char *zErrMsg; /* An error message */
Vdbe *pVdbe; /* An engine for executing database bytecode */
int rc; /* Return code from execution */
u8 colNamesSet; /* TRUE after OP_ColumnName has been issued to pVdbe */
u8 checkSchema; /* Causes schema cookie check after an error */
u8 nested; /* Number of nested calls to the parser/code generator */
u8 nTempReg; /* Number of temporary registers in aTempReg[] */
u8 isMultiWrite; /* True if statement may modify/insert multiple rows */
u8 mayAbort; /* True if statement may throw an ABORT exception */
u8 hasCompound; /* Need to invoke convertCompoundSelectToSubquery() */
u8 okConstFactor; /* OK to factor out constants */
u8 disableLookaside; /* Number of times lookaside has been disabled */
int nRangeReg; /* Size of the temporary register block */
int iRangeReg; /* First register in temporary register block */
int nErr; /* Number of errors seen */
int nTab; /* Number of previously allocated VDBE cursors */
int nMem; /* Number of memory cells used so far */
int nOpAlloc; /* Number of slots allocated for Vdbe.aOp[] */
int szOpAlloc; /* Bytes of memory space allocated for Vdbe.aOp[] */
int iSelfTab; /* Table associated with an index on expr, or negative
** of the base register during check-constraint eval */
int nLabel; /* Number of labels used */
int *aLabel; /* Space to hold the labels */
ExprList *pConstExpr;/* Constant expressions */
Token constraintName;/* Name of the constraint currently being parsed */
yDbMask writeMask; /* Start a write transaction on these databases */
yDbMask cookieMask; /* Bitmask of schema verified databases */
int regRowid; /* Register holding rowid of CREATE TABLE entry */
int regRoot; /* Register holding root page number for new objects */
int nMaxArg; /* Max args passed to user function by sub-program */
int nSelect; /* Number of SELECT stmts. Counter for Select.selId */
#ifndef SQLITE_OMIT_SHARED_CACHE
int nTableLock; /* Number of locks in aTableLock */
TableLock *aTableLock; /* Required table locks for shared-cache mode */
#endif
AutoincInfo *pAinc; /* Information about AUTOINCREMENT counters */
Parse *pToplevel; /* Parse structure for main program (or NULL) */
Table *pTriggerTab; /* Table triggers are being coded for */
int addrCrTab; /* Address of OP_CreateBtree opcode on CREATE TABLE */
u32 nQueryLoop; /* Est number of iterations of a query (10*log2(N)) */
u32 oldmask; /* Mask of old.* columns referenced */
u32 newmask; /* Mask of new.* columns referenced */
u8 eTriggerOp; /* TK_UPDATE, TK_INSERT or TK_DELETE */
u8 eOrconf; /* Default ON CONFLICT policy for trigger steps */
u8 disableTriggers; /* True to disable triggers */
/**************************************************************************
** Fields above must be initialized to zero. The fields that follow,
** down to the beginning of the recursive section, do not need to be
** initialized as they will be set before being used. The boundary is
** determined by offsetof(Parse,aTempReg).
**************************************************************************/
int aTempReg[8]; /* Holding area for temporary registers */
Token sNameToken; /* Token with unqualified schema object name */
/************************************************************************
** Above is constant between recursions. Below is reset before and after
** each recursion. The boundary between these two regions is determined
** using offsetof(Parse,sLastToken) so the sLastToken field must be the
** first field in the recursive region.
************************************************************************/
Token sLastToken; /* The last token parsed */
ynVar nVar; /* Number of '?' variables seen in the SQL so far */
u8 iPkSortOrder; /* ASC or DESC for INTEGER PRIMARY KEY */
u8 explain; /* True if the EXPLAIN flag is found on the query */
#if !(defined(SQLITE_OMIT_VIRTUALTABLE) && defined(SQLITE_OMIT_ALTERTABLE))
u8 eParseMode; /* PARSE_MODE_XXX constant */
#endif
#ifndef SQLITE_OMIT_VIRTUALTABLE
int nVtabLock; /* Number of virtual tables to lock */
#endif
int nHeight; /* Expression tree height of current sub-select */
#ifndef SQLITE_OMIT_EXPLAIN
int addrExplain; /* Address of current OP_Explain opcode */
#endif
VList *pVList; /* Mapping between variable names and numbers */
Vdbe *pReprepare; /* VM being reprepared (sqlite3Reprepare()) */
const char *zTail; /* All SQL text past the last semicolon parsed */
Table *pNewTable; /* A table being constructed by CREATE TABLE */
Index *pNewIndex; /* An index being constructed by CREATE INDEX */
Trigger *pNewTrigger; /* Trigger under construct by a CREATE TRIGGER */
const char *zAuthContext; /* The 6th parameter to db->xAuth callbacks */
#ifndef SQLITE_OMIT_VIRTUALTABLE
Token sArg; /* Complete text of a module argument */
Table **apVtabLock; /* Pointer to virtual tables needing locking */
#endif
Table *pZombieTab; /* List of Table objects to delete after code gen */
TriggerPrg *pTriggerPrg; /* Linked list of coded triggers */
With *pWith; /* Current WITH clause, or NULL */
With *pWithToFree; /* Free this WITH object at the end of the parse */
#ifndef SQLITE_OMIT_ALTERTABLE
RenameToken *pRename; /* Tokens subject to renaming by ALTER TABLE */
#endif
};
#define PARSE_MODE_NORMAL 0
#define PARSE_MODE_DECLARE_VTAB 1
#define PARSE_MODE_RENAME_COLUMN 2
pCx->seekResult = pOp->p2;
pCx->isTable = 1;
/* Give this pseudo-cursor a fake BtCursor pointer so that pCx
** can be safely passed to sqlite3VdbeCursorMoveto(). This avoids a test
** for pCx->eCurType==CURTYPE_BTREE inside of sqlite3VdbeCursorMoveto()
** which is a performance optimization */
pCx->uc.pCursor = sqlite3BtreeFakeValidCursor();
assert( pOp->p5==0 );
break;
}
/* Opcode: Close P1 * * * *
**
** Close a cursor previously opened as P1. If P1 is not
** currently open, this instruction is a no-op.
*/
case OP_Close: {
assert( pOp->p1>=0 && pOp->p1<p->nCursor );
sqlite3VdbeFreeCursor(p, p->apCsr[pOp->p1]);
p->apCsr[pOp->p1] = 0;
break;
}
#ifdef SQLITE_ENABLE_COLUMN_USED_MASK
/* Opcode: ColumnsUsed P1 * * P4 *
**
** This opcode (which only exists if SQLite was compiled with
** SQLITE_ENABLE_COLUMN_USED_MASK) identifies which columns of the
** table or index for cursor P1 are used. P4 is a 64-bit integer
** (P4_INT64) in which the first 63 bits are one for each of the
** first 63 columns of the table or index that are actually used
** by the cursor. The high-order bit is set if any column after
** the 64th is used.
*/
case OP_ColumnsUsed: {
VdbeCursor *pC;
pC = p->apCsr[pOp->p1];
assert( pC->eCurType==CURTYPE_BTREE );
pC->maskUsed = *(u64*)pOp->p4.pI64;
break;
}
#endif
/* Opcode: SeekGE P1 P2 P3 P4 *
** Synopsis: key=r[P3@P4]
**
** If cursor P1 refers to an SQL table (B-Tree that uses integer keys),
** use the value in register P3 as the key. If cursor P1 refers
** to an SQL index, then P3 is the first in an array of P4 registers
** that are used as an unpacked index key.
**
** Reposition cursor P1 so that it points to the smallest entry that
** is greater than or equal to the key value. If there are no records
** greater than or equal to the key and P2 is not zero, then jump to P2.
**
** If the cursor P1 was opened using the OPFLAG_SEEKEQ flag, then this
** opcode will always land on a record that equally equals the key, or
** else jump immediately to P2. When the cursor is OPFLAG_SEEKEQ, this
** opcode must be followed by an IdxLE opcode with the same arguments.
** The IdxLE opcode will be skipped if this opcode succeeds, but the
** IdxLE opcode will be used on subsequent loop iterations.
**
** This opcode leaves the cursor configured to move in forward order,
** from the beginning toward the end. In other words, the cursor is
** configured to use Next, not Prev.
**
** See also: Found, NotFound, SeekLt, SeekGt, SeekLe
*/
/* Opcode: SeekGT P1 P2 P3 P4 *
** Synopsis: key=r[P3@P4]
**
** If cursor P1 refers to an SQL table (B-Tree that uses integer keys),
** use the value in register P3 as a key. If cursor P1 refers
** to an SQL index, then P3 is the first in an array of P4 registers
** that are used as an unpacked index key.
**
** Reposition cursor P1 so that it points to the smallest entry that
** is greater than the key value. If there are no records greater than
** the key and P2 is not zero, then jump to P2.
**
** This opcode leaves the cursor configured to move in forward order,
** from the beginning toward the end. In other words, the cursor is
** configured to use Next, not Prev.
**
** See also: Found, NotFound, SeekLt, SeekGe, SeekLe
*/
/* Opcode: SeekLT P1 P2 P3 P4 *
** Synopsis: key=r[P3@P4]
**
** If cursor P1 refers to an SQL table (B-Tree that uses integer keys),
** use the value in register P3 as a key. If cursor P1 refers
** to an SQL index, then P3 is the first in an array of P4 registers
** that are used as an unpacked index key.
**
** Reposition cursor P1 so that it points to the largest entry that
** is less than the key value. If there are no records less than
** the key and P2 is not zero, then jump to P2.
**
** This opcode leaves the cursor configured to move in reverse order,
** from the end toward the beginning. In other words, the cursor is
** configured to use Prev, not Next.
**
** See also: Found, NotFound, SeekGt, SeekGe, SeekLe
*/
/* Opcode: SeekLE P1 P2 P3 P4 *
** Synopsis: key=r[P3@P4]
**
** If cursor P1 refers to an SQL table (B-Tree that uses integer keys),
** use the value in register P3 as a key. If cursor P1 refers
** to an SQL index, then P3 is the first in an array of P4 registers
** that are used as an unpacked index key.
**
** Reposition cursor P1 so that it points to the largest entry that
** is less than or equal to the key value. If there are no records
** less than or equal to the key and P2 is not zero, then jump to P2.
**
** This opcode leaves the cursor configured to move in reverse order,
** from the end toward the beginning. In other words, the cursor is
** configured to use Prev, not Next.
**
** If the cursor P1 was opened using the OPFLAG_SEEKEQ flag, then this
** opcode will always land on a record that equally equals the key, or
** else jump immediately to P2. When the cursor is OPFLAG_SEEKEQ, this
** opcode must be followed by an IdxGE opcode with the same arguments.
** The IdxGE opcode will be skipped if this opcode succeeds, but the
** IdxGE opcode will be used on subsequent loop iterations.
**
** See also: Found, NotFound, SeekGt, SeekGe, SeekLt
*/
case OP_SeekLT: /* jump, in3, group */
case OP_SeekLE: /* jump, in3, group */
case OP_SeekGE: /* jump, in3, group */
case OP_SeekGT: { /* jump, in3, group */
int res; /* Comparison result */
int oc; /* Opcode */
VdbeCursor *pC; /* The cursor to seek */
UnpackedRecord r; /* The key to seek for */
int nField; /* Number of columns or fields in the key */
i64 iKey; /* The rowid we are to seek to */
int eqOnly; /* Only interested in == results */
assert( pOp->p1>=0 && pOp->p1<p->nCursor );
assert( pOp->p2!=0 );
pC = p->apCsr[pOp->p1];
assert( pC!=0 );
assert( pC->eCurType==CURTYPE_BTREE );
assert( OP_SeekLE == OP_SeekLT+1 );
assert( OP_SeekGE == OP_SeekLT+2 );
assert( OP_SeekGT == OP_SeekLT+3 );
assert( pC->isOrdered );
assert( pC->uc.pCursor!=0 );
oc = pOp->opcode;
eqOnly = 0;
pC->nullRow = 0;
#ifdef SQLITE_DEBUG
pC->seekOp = pOp->opcode;
#endif
if( pC->isTable ){
/* The BTREE_SEEK_EQ flag is only set on index cursors */
assert( sqlite3BtreeCursorHasHint(pC->uc.pCursor, BTREE_SEEK_EQ)==0
|| CORRUPT_DB );
/* The input value in P3 might be of any type: integer, real, string,
** blob, or NULL. But it needs to be an integer before we can do
** the seek, so convert it. */
pIn3 = &aMem[pOp->p3];
if( (pIn3->flags & (MEM_Int|MEM_Real|MEM_Str))==MEM_Str ){
applyNumericAffinity(pIn3, 0);
}
iKey = sqlite3VdbeIntValue(pIn3);
/* If the P3 value could not be converted into an integer without
** loss of information, then special processing is required... */
if( (pIn3->flags & MEM_Int)==0 ){
if( (pIn3->flags & MEM_Real)==0 ){
/* If the P3 value cannot be converted into any kind of a number,
** then the seek is not possible, so jump to P2 */
VdbeBranchTaken(1,2); goto jump_to_p2;
break;
}
/* If the approximation iKey is larger than the actual real search
** term, substitute >= for > and < for <=. e.g. if the search term
** is 4.9 and the integer approximation 5:
**
pIn2 = &aMem[pOp->p2];
sqlite3VdbeMemIntegerify(pIn2);
if( pIn1->u.i<pIn2->u.i){
pIn1->u.i = pIn2->u.i;
}
break;
}
#endif /* SQLITE_OMIT_AUTOINCREMENT */
/* Opcode: IfPos P1 P2 P3 * *
** Synopsis: if r[P1]>0 then r[P1]-=P3, goto P2
**
** Register P1 must contain an integer.
** If the value of register P1 is 1 or greater, subtract P3 from the
** value in P1 and jump to P2.
**
** If the initial value of register P1 is less than 1, then the
** value is unchanged and control passes through to the next instruction.
*/
case OP_IfPos: { /* jump, in1 */
pIn1 = &aMem[pOp->p1];
assert( pIn1->flags&MEM_Int );
VdbeBranchTaken( pIn1->u.i>0, 2);
if( pIn1->u.i>0 ){
pIn1->u.i -= pOp->p3;
goto jump_to_p2;
}
break;
}
/* Opcode: OffsetLimit P1 P2 P3 * *
** Synopsis: if r[P1]>0 then r[P2]=r[P1]+max(0,r[P3]) else r[P2]=(-1)
**
** This opcode performs a commonly used computation associated with
** LIMIT and OFFSET process. r[P1] holds the limit counter. r[P3]
** holds the offset counter. The opcode computes the combined value
** of the LIMIT and OFFSET and stores that value in r[P2]. The r[P2]
** value computed is the total number of rows that will need to be
** visited in order to complete the query.
**
** If r[P3] is zero or negative, that means there is no OFFSET
** and r[P2] is set to be the value of the LIMIT, r[P1].
**
** if r[P1] is zero or negative, that means there is no LIMIT
** and r[P2] is set to -1.
**
** Otherwise, r[P2] is set to the sum of r[P1] and r[P3].
*/
case OP_OffsetLimit: { /* in1, out2, in3 */
i64 x;
pIn1 = &aMem[pOp->p1];
pIn3 = &aMem[pOp->p3];
pOut = out2Prerelease(p, pOp);
assert( pIn1->flags & MEM_Int );
assert( pIn3->flags & MEM_Int );
x = pIn1->u.i;
if( x<=0 || sqlite3AddInt64(&x, pIn3->u.i>0?pIn3->u.i:0) ){
/* If the LIMIT is less than or equal to zero, loop forever. This
** is documented. But also, if the LIMIT+OFFSET exceeds 2^63 then
** also loop forever. This is undocumented. In fact, one could argue
** that the loop should terminate. But assuming 1 billion iterations
** per second (far exceeding the capabilities of any current hardware)
** it would take nearly 300 years to actually reach the limit. So
** looping forever is a reasonable approximation. */
pOut->u.i = -1;
}else{
pOut->u.i = x;
}
break;
}
/* Opcode: IfNotZero P1 P2 * * *
** Synopsis: if r[P1]!=0 then r[P1]--, goto P2
**
** Register P1 must contain an integer. If the content of register P1 is
** initially greater than zero, then decrement the value in register P1.
** If it is non-zero (negative or positive) and then also jump to P2.
** If register P1 is initially zero, leave it unchanged and fall through.
*/
case OP_IfNotZero: { /* jump, in1 */
pIn1 = &aMem[pOp->p1];
assert( pIn1->flags&MEM_Int );
VdbeBranchTaken(pIn1->u.i<0, 2);
if( pIn1->u.i ){
if( pIn1->u.i>0 ) pIn1->u.i--;
goto jump_to_p2;
}
break;
}
/* Opcode: DecrJumpZero P1 P2 * * *
** Synopsis: if (--r[P1])==0 goto P2
**
** Register P1 must hold an integer. Decrement the value in P1
** and jump to P2 if the new value is exactly zero.
*/
case OP_DecrJumpZero: { /* jump, in1 */
pIn1 = &aMem[pOp->p1];
assert( pIn1->flags&MEM_Int );
if( pIn1->u.i>SMALLEST_INT64 ) pIn1->u.i--;
VdbeBranchTaken(pIn1->u.i==0, 2);
if( pIn1->u.i==0 ) goto jump_to_p2;
break;
}
/* Opcode: AggStep * P2 P3 P4 P5
** Synopsis: accum=r[P3] step(r[P2@P5])
**
** Execute the xStep function for an aggregate.
** The function has P5 arguments. P4 is a pointer to the
** FuncDef structure that specifies the function. Register P3 is the
** accumulator.
**
** The P5 arguments are taken from register P2 and its
** successors.
*/
/* Opcode: AggInverse * P2 P3 P4 P5
** Synopsis: accum=r[P3] inverse(r[P2@P5])
**
** Execute the xInverse function for an aggregate.
/* Finish the loop through table entries that match term pOrTerm. */
sqlite3WhereEnd(pSubWInfo);
}
}
}
ExplainQueryPlanPop(pParse);
pLevel->u.pCovidx = pCov;
if( pCov ) pLevel->iIdxCur = iCovCur;
if( pAndExpr ){
pAndExpr->pLeft = 0;
sqlite3ExprDelete(db, pAndExpr);
}
sqlite3VdbeChangeP1(v, iRetInit, sqlite3VdbeCurrentAddr(v));
sqlite3VdbeGoto(v, pLevel->addrBrk);
sqlite3VdbeResolveLabel(v, iLoopBody);
if( pWInfo->nLevel>1 ) sqlite3StackFree(db, pOrTab);
if( !untestedTerms ) disableTerm(pLevel, pTerm);
}else
#endif /* SQLITE_OMIT_OR_OPTIMIZATION */
{
/* Case 6: There is no usable index. We must do a complete
** scan of the entire table.
*/
static const u8 aStep[] = { OP_Next, OP_Prev };
static const u8 aStart[] = { OP_Rewind, OP_Last };
assert( bRev==0 || bRev==1 );
if( pTabItem->fg.isRecursive ){
/* Tables marked isRecursive have only a single row that is stored in
** a pseudo-cursor. No need to Rewind or Next such cursors. */
pLevel->op = OP_Noop;
}else{
codeCursorHint(pTabItem, pWInfo, pLevel, 0);
pLevel->op = aStep[bRev];
pLevel->p1 = iCur;
pLevel->p2 = 1 + sqlite3VdbeAddOp2(v, aStart[bRev], iCur, addrHalt);
VdbeCoverageIf(v, bRev==0);
VdbeCoverageIf(v, bRev!=0);
pLevel->p5 = SQLITE_STMTSTATUS_FULLSCAN_STEP;
}
}
#ifdef SQLITE_ENABLE_STMT_SCANSTATUS
pLevel->addrVisit = sqlite3VdbeCurrentAddr(v);
#endif
/* Insert code to test every subexpression that can be completely
** computed using the current set of tables.
**
** This loop may run between one and three times, depending on the
** constraints to be generated. The value of stack variable iLoop
** determines the constraints coded by each iteration, as follows:
**
** iLoop==1: Code only expressions that are entirely covered by pIdx.
** iLoop==2: Code remaining expressions that do not contain correlated
** sub-queries.
** iLoop==3: Code all remaining expressions.
**
** An effort is made to skip unnecessary iterations of the loop.
*/
iLoop = (pIdx ? 1 : 2);
do{
int iNext = 0; /* Next value for iLoop */
for(pTerm=pWC->a, j=pWC->nTerm; j>0; j--, pTerm++){
Expr *pE;
int skipLikeAddr = 0;
testcase( pTerm->wtFlags & TERM_VIRTUAL );
testcase( pTerm->wtFlags & TERM_CODED );
if( pTerm->wtFlags & (TERM_VIRTUAL|TERM_CODED) ) continue;
if( (pTerm->prereqAll & pLevel->notReady)!=0 ){
testcase( pWInfo->untestedTerms==0
&& (pWInfo->wctrlFlags & WHERE_OR_SUBCLAUSE)!=0 );
pWInfo->untestedTerms = 1;
continue;
}
pE = pTerm->pExpr;
assert( pE!=0 );
if( (pTabItem->fg.jointype&JT_LEFT) && !ExprHasProperty(pE,EP_FromJoin) ){
continue;
}
if( iLoop==1 && !sqlite3ExprCoveredByIndex(pE, pLevel->iTabCur, pIdx) ){
iNext = 2;
continue;
}
if( iLoop<3 && (pTerm->wtFlags & TERM_VARSELECT) ){
if( iNext==0 ) iNext = 3;
continue;
}
if( (pTerm->wtFlags & TERM_LIKECOND)!=0 ){
/* If the TERM_LIKECOND flag is set, that means that the range search
** is sufficient to guarantee that the LIKE operator is true, so we
** can skip the call to the like(A,B) function. But this only works
** for strings. So do not skip the call to the function on the pass
** that compares BLOBs. */
#ifdef SQLITE_LIKE_DOESNT_MATCH_BLOBS
continue;
#else
u32 x = pLevel->iLikeRepCntr;
if( x>0 ){
skipLikeAddr = sqlite3VdbeAddOp1(v, (x&1)?OP_IfNot:OP_If,(int)(x>>1));
}
VdbeCoverage(v);
#endif
}
#ifdef WHERETRACE_ENABLED /* 0xffff */
if( sqlite3WhereTrace ){
VdbeNoopComment((v, "WhereTerm[%d] (%p) priority=%d",
pWC->nTerm-j, pTerm, iLoop));
}
#endif
sqlite3ExprIfFalse(pParse, pE, addrCont, SQLITE_JUMPIFNULL);
if( skipLikeAddr ) sqlite3VdbeJumpHere(v, skipLikeAddr);
pTerm->wtFlags |= TERM_CODED;
}
iLoop = iNext;
}while( iLoop>0 );
char aff;
if( pTerm->leftCursor!=pSrc->iCursor ) return 0;
if( (pTerm->eOperator & (WO_EQ|WO_IS))==0 ) return 0;
if( (pSrc->fg.jointype & JT_LEFT)
&& !ExprHasProperty(pTerm->pExpr, EP_FromJoin)
&& (pTerm->eOperator & WO_IS)
){
/* Cannot use an IS term from the WHERE clause as an index driver for
** the RHS of a LEFT JOIN. Such a term can only be used if it is from
** the ON clause. */
return 0;
}
if( (pTerm->prereqRight & notReady)!=0 ) return 0;
if( pTerm->u.leftColumn<0 ) return 0;
aff = pSrc->pTab->aCol[pTerm->u.leftColumn].affinity;
if( !sqlite3IndexAffinityOk(pTerm->pExpr, aff) ) return 0;
testcase( pTerm->pExpr->op==TK_IS );
return 1;
}
#endif
#ifndef SQLITE_OMIT_AUTOMATIC_INDEX
/*
** Generate code to construct the Index object for an automatic index
** and to set up the WhereLevel object pLevel so that the code generator
** makes use of the automatic index.
*/
static void constructAutomaticIndex(
Parse *pParse, /* The parsing context */
WhereClause *pWC, /* The WHERE clause */
struct SrcList_item *pSrc, /* The FROM clause term to get the next index */
Bitmask notReady, /* Mask of cursors that are not available */
WhereLevel *pLevel /* Write new index here */
){
int nKeyCol; /* Number of columns in the constructed index */
WhereTerm *pTerm; /* A single term of the WHERE clause */
WhereTerm *pWCEnd; /* End of pWC->a[] */
Index *pIdx; /* Object describing the transient index */
Vdbe *v; /* Prepared statement under construction */
int addrInit; /* Address of the initialization bypass jump */
Table *pTable; /* The table being indexed */
int addrTop; /* Top of the index fill loop */
int regRecord; /* Register holding an index record */
int n; /* Column counter */
int i; /* Loop counter */
int mxBitCol; /* Maximum column in pSrc->colUsed */
CollSeq *pColl; /* Collating sequence to on a column */
WhereLoop *pLoop; /* The Loop object */
char *zNotUsed; /* Extra space on the end of pIdx */
Bitmask idxCols; /* Bitmap of columns used for indexing */
Bitmask extraCols; /* Bitmap of additional columns */
u8 sentWarning = 0; /* True if a warnning has been issued */
Expr *pPartial = 0; /* Partial Index Expression */
int iContinue = 0; /* Jump here to skip excluded rows */
struct SrcList_item *pTabItem; /* FROM clause term being indexed */
int addrCounter = 0; /* Address where integer counter is initialized */
int regBase; /* Array of registers where record is assembled */
/* Generate code to skip over the creation and initialization of the
** transient index on 2nd and subsequent iterations of the loop. */
v = pParse->pVdbe;
assert( v!=0 );
addrInit = sqlite3VdbeAddOp0(v, OP_Once); VdbeCoverage(v);
/* Count the number of columns that will be added to the index
** and used to match WHERE clause constraints */
nKeyCol = 0;
pTable = pSrc->pTab;
pWCEnd = &pWC->a[pWC->nTerm];
pLoop = pLevel->pWLoop;
idxCols = 0;
for(pTerm=pWC->a; pTerm<pWCEnd; pTerm++){
Expr *pExpr = pTerm->pExpr;
assert( !ExprHasProperty(pExpr, EP_FromJoin) /* prereq always non-zero */
|| pExpr->iRightJoinTable!=pSrc->iCursor /* for the right-hand */
|| pLoop->prereq!=0 ); /* table of a LEFT JOIN */
if( pLoop->prereq==0
&& (pTerm->wtFlags & TERM_VIRTUAL)==0
&& !ExprHasProperty(pExpr, EP_FromJoin)
&& sqlite3ExprIsTableConstant(pExpr, pSrc->iCursor) ){
pPartial = sqlite3ExprAnd(pParse->db, pPartial,
sqlite3ExprDup(pParse->db, pExpr, 0));
}
if( termCanDriveIndex(pTerm, pSrc, notReady) ){
int iCol = pTerm->u.leftColumn;
Bitmask cMask = iCol>=BMS ? MASKBIT(BMS-1) : MASKBIT(iCol);
testcase( iCol==BMS );
testcase( iCol==BMS-1 );
if( !sentWarning ){
sqlite3_log(SQLITE_WARNING_AUTOINDEX,
"automatic index on %s(%s)", pTable->zName,
pTable->aCol[iCol].zName);
sentWarning = 1;
}
if( (idxCols & cMask)==0 ){
if( whereLoopResize(pParse->db, pLoop, nKeyCol+1) ){
goto end_auto_index_create;
}
pLoop->aLTerm[nKeyCol++] = pTerm;
idxCols |= cMask;
}
}
}
assert( nKeyCol>0 );
pLoop->u.btree.nEq = pLoop->nLTerm = nKeyCol;
pLoop->wsFlags = WHERE_COLUMN_EQ | WHERE_IDX_ONLY | WHERE_INDEXED
| WHERE_AUTO_INDEX;
/* Count the number of additional columns needed to create a
** covering index. A "covering index" is an index that contains all
** columns that are needed by the query. With a covering index, the
** original table never needs to be accessed. Automatic indices must
** be a covering index because the index will not be updated if the
** original table changes and the index and table cannot both be used
** if they go out of sync.
*/
extraCols = pSrc->colUsed & (~idxCols | MASKBIT(BMS-1));
mxBitCol = MIN(BMS-1,pTable->nCol);
testcase( pTable->nCol==BMS-1 );
testcase( pTable->nCol==BMS-2 );
char idxaff = 0; /* Indexed columns affinity */
CollSeq *pColl; /* Comparison collation sequence */
Expr *pLhs = pTerm->pExpr->pLeft->x.pList->a[i].pExpr;
Expr *pRhs = pTerm->pExpr->pRight;
if( pRhs->flags & EP_xIsSelect ){
pRhs = pRhs->x.pSelect->pEList->a[i].pExpr;
}else{
pRhs = pRhs->x.pList->a[i].pExpr;
}
/* Check that the LHS of the comparison is a column reference to
** the right column of the right source table. And that the sort
** order of the index column is the same as the sort order of the
** leftmost index column. */
if( pLhs->op!=TK_COLUMN
|| pLhs->iTable!=iCur
|| pLhs->iColumn!=pIdx->aiColumn[i+nEq]
|| pIdx->aSortOrder[i+nEq]!=pIdx->aSortOrder[nEq]
){
break;
}
testcase( pLhs->iColumn==XN_ROWID );
aff = sqlite3CompareAffinity(pRhs, sqlite3ExprAffinity(pLhs));
idxaff = sqlite3TableColumnAffinity(pIdx->pTable, pLhs->iColumn);
if( aff!=idxaff ) break;
pColl = sqlite3BinaryCompareCollSeq(pParse, pLhs, pRhs);
if( pColl==0 ) break;
if( sqlite3StrICmp(pColl->zName, pIdx->azColl[i+nEq]) ) break;
}
return i;
}
/*
** Adjust the cost C by the costMult facter T. This only occurs if
** compiled with -DSQLITE_ENABLE_COSTMULT
*/
#ifdef SQLITE_ENABLE_COSTMULT
# define ApplyCostMultiplier(C,T) C += T
#else
# define ApplyCostMultiplier(C,T)
#endif
/*
** We have so far matched pBuilder->pNew->u.btree.nEq terms of the
** index pIndex. Try to match one more.
**
** When this function is called, pBuilder->pNew->nOut contains the
** number of rows expected to be visited by filtering using the nEq
** terms only. If it is modified, this value is restored before this
** function returns.
**
** If pProbe->tnum==0, that means pIndex is a fake index used for the
** INTEGER PRIMARY KEY.
*/
static int whereLoopAddBtreeIndex(
WhereLoopBuilder *pBuilder, /* The WhereLoop factory */
struct SrcList_item *pSrc, /* FROM clause term being analyzed */
Index *pProbe, /* An index on pSrc */
LogEst nInMul /* log(Number of iterations due to IN) */
){
WhereInfo *pWInfo = pBuilder->pWInfo; /* WHERE analyse context */
Parse *pParse = pWInfo->pParse; /* Parsing context */
sqlite3 *db = pParse->db; /* Database connection malloc context */
WhereLoop *pNew; /* Template WhereLoop under construction */
WhereTerm *pTerm; /* A WhereTerm under consideration */
int opMask; /* Valid operators for constraints */
WhereScan scan; /* Iterator for WHERE terms */
Bitmask saved_prereq; /* Original value of pNew->prereq */
u16 saved_nLTerm; /* Original value of pNew->nLTerm */
u16 saved_nEq; /* Original value of pNew->u.btree.nEq */
u16 saved_nBtm; /* Original value of pNew->u.btree.nBtm */
u16 saved_nTop; /* Original value of pNew->u.btree.nTop */
u16 saved_nSkip; /* Original value of pNew->nSkip */
u32 saved_wsFlags; /* Original value of pNew->wsFlags */
LogEst saved_nOut; /* Original value of pNew->nOut */
int rc = SQLITE_OK; /* Return code */
LogEst rSize; /* Number of rows in the table */
LogEst rLogSize; /* Logarithm of table size */
WhereTerm *pTop = 0, *pBtm = 0; /* Top and bottom range constraints */
pNew = pBuilder->pNew;
if( db->mallocFailed ) return SQLITE_NOMEM_BKPT;
WHERETRACE(0x800, ("BEGIN %s.addBtreeIdx(%s), nEq=%d\n",
pProbe->pTable->zName,pProbe->zName, pNew->u.btree.nEq));
assert( (pNew->wsFlags & WHERE_VIRTUALTABLE)==0 );
assert( (pNew->wsFlags & WHERE_TOP_LIMIT)==0 );
if( pNew->wsFlags & WHERE_BTM_LIMIT ){
opMask = WO_LT|WO_LE;
}else{
assert( pNew->u.btree.nBtm==0 );
opMask = WO_EQ|WO_IN|WO_GT|WO_GE|WO_LT|WO_LE|WO_ISNULL|WO_IS;
}
if( pProbe->bUnordered ) opMask &= ~(WO_GT|WO_GE|WO_LT|WO_LE);
assert( pNew->u.btree.nEq<pProbe->nColumn );
saved_nEq = pNew->u.btree.nEq;
saved_nBtm = pNew->u.btree.nBtm;
saved_nTop = pNew->u.btree.nTop;
saved_nSkip = pNew->nSkip;
saved_nLTerm = pNew->nLTerm;
saved_wsFlags = pNew->wsFlags;
saved_prereq = pNew->prereq;
saved_nOut = pNew->nOut;
pTerm = whereScanInit(&scan, pBuilder->pWC, pSrc->iCursor, saved_nEq,
opMask, pProbe);
pNew->rSetup = 0;
rSize = pProbe->aiRowLogEst[0];
rLogSize = estLog(rSize);
for(; rc==SQLITE_OK && pTerm!=0; pTerm = whereScanNext(&scan)){
u16 eOp = pTerm->eOperator; /* Shorthand for pTerm->eOperator */
LogEst rCostIdx;
LogEst nOutUnadjusted; /* nOut before IN() and WHERE adjustments */
int nIn = 0;
#ifdef SQLITE_ENABLE_STAT3_OR_STAT4
int nRecValid = pBuilder->nRecValid;
#endif
if( (eOp==WO_ISNULL || (pTerm->wtFlags&TERM_VNULL)!=0)
LogEst mxUnsorted = 0; /* Maximum unsorted cost of a set of path */
int nTo, nFrom; /* Number of valid entries in aTo[] and aFrom[] */
WherePath *aFrom; /* All nFrom paths at the previous level */
WherePath *aTo; /* The nTo best paths at the current level */
WherePath *pFrom; /* An element of aFrom[] that we are working on */
WherePath *pTo; /* An element of aTo[] that we are working on */
WhereLoop *pWLoop; /* One of the WhereLoop objects */
WhereLoop **pX; /* Used to divy up the pSpace memory */
LogEst *aSortCost = 0; /* Sorting and partial sorting costs */
char *pSpace; /* Temporary memory used by this routine */
int nSpace; /* Bytes of space allocated at pSpace */
pParse = pWInfo->pParse;
db = pParse->db;
nLoop = pWInfo->nLevel;
/* TUNING: For simple queries, only the best path is tracked.
** For 2-way joins, the 5 best paths are followed.
** For joins of 3 or more tables, track the 10 best paths */
mxChoice = (nLoop<=1) ? 1 : (nLoop==2 ? 5 : 10);
assert( nLoop<=pWInfo->pTabList->nSrc );
WHERETRACE(0x002, ("---- begin solver. (nRowEst=%d)\n", nRowEst));
/* If nRowEst is zero and there is an ORDER BY clause, ignore it. In this
** case the purpose of this call is to estimate the number of rows returned
** by the overall query. Once this estimate has been obtained, the caller
** will invoke this function a second time, passing the estimate as the
** nRowEst parameter. */
if( pWInfo->pOrderBy==0 || nRowEst==0 ){
nOrderBy = 0;
}else{
nOrderBy = pWInfo->pOrderBy->nExpr;
}
/* Allocate and initialize space for aTo, aFrom and aSortCost[] */
nSpace = (sizeof(WherePath)+sizeof(WhereLoop*)*nLoop)*mxChoice*2;
nSpace += sizeof(LogEst) * nOrderBy;
pSpace = sqlite3DbMallocRawNN(db, nSpace);
if( pSpace==0 ) return SQLITE_NOMEM_BKPT;
aTo = (WherePath*)pSpace;
aFrom = aTo+mxChoice;
memset(aFrom, 0, sizeof(aFrom[0]));
pX = (WhereLoop**)(aFrom+mxChoice);
for(ii=mxChoice*2, pFrom=aTo; ii>0; ii--, pFrom++, pX += nLoop){
pFrom->aLoop = pX;
}
if( nOrderBy ){
/* If there is an ORDER BY clause and it is not being ignored, set up
** space for the aSortCost[] array. Each element of the aSortCost array
** is either zero - meaning it has not yet been initialized - or the
** cost of sorting nRowEst rows of data where the first X terms of
** the ORDER BY clause are already in order, where X is the array
** index. */
aSortCost = (LogEst*)pX;
memset(aSortCost, 0, sizeof(LogEst) * nOrderBy);
}
assert( aSortCost==0 || &pSpace[nSpace]==(char*)&aSortCost[nOrderBy] );
assert( aSortCost!=0 || &pSpace[nSpace]==(char*)pX );
/* Seed the search with a single WherePath containing zero WhereLoops.
**
** TUNING: Do not let the number of iterations go above 28. If the cost
** of computing an automatic index is not paid back within the first 28
** rows, then do not use the automatic index. */
aFrom[0].nRow = MIN(pParse->nQueryLoop, 48); assert( 48==sqlite3LogEst(28) );
nFrom = 1;
assert( aFrom[0].isOrdered==0 );
if( nOrderBy ){
/* If nLoop is zero, then there are no FROM terms in the query. Since
** in this case the query may return a maximum of one row, the results
** are already in the requested order. Set isOrdered to nOrderBy to
** indicate this. Or, if nLoop is greater than zero, set isOrdered to
** -1, indicating that the result set may or may not be ordered,
** depending on the loops added to the current plan. */
aFrom[0].isOrdered = nLoop>0 ? -1 : nOrderBy;
}
/* Compute successively longer WherePaths using the previous generation
** of WherePaths as the basis for the next. Keep track of the mxChoice
** best paths at each generation */
for(iLoop=0; iLoop<nLoop; iLoop++){
nTo = 0;
for(ii=0, pFrom=aFrom; ii<nFrom; ii++, pFrom++){
for(pWLoop=pWInfo->pLoops; pWLoop; pWLoop=pWLoop->pNextLoop){
LogEst nOut; /* Rows visited by (pFrom+pWLoop) */
LogEst rCost; /* Cost of path (pFrom+pWLoop) */
LogEst rUnsorted; /* Unsorted cost of (pFrom+pWLoop) */
i8 isOrdered = pFrom->isOrdered; /* isOrdered for (pFrom+pWLoop) */
Bitmask maskNew; /* Mask of src visited by (..) */
Bitmask revMask = 0; /* Mask of rev-order loops for (..) */
if( (pWLoop->prereq & ~pFrom->maskLoop)!=0 ) continue;
if( (pWLoop->maskSelf & pFrom->maskLoop)!=0 ) continue;
if( (pWLoop->wsFlags & WHERE_AUTO_INDEX)!=0 && pFrom->nRow<3 ){
/* Do not use an automatic index if the this loop is expected
** to run less than 1.25 times. It is tempting to also exclude
** automatic index usage on an outer loop, but sometimes an automatic
** index is useful in the outer loop of a correlated subquery. */
assert( 10==sqlite3LogEst(2) );
continue;
}
/* At this point, pWLoop is a candidate to be the next loop.
** Compute its cost */
rUnsorted = sqlite3LogEstAdd(pWLoop->rSetup,pWLoop->rRun + pFrom->nRow);
rUnsorted = sqlite3LogEstAdd(rUnsorted, pFrom->rUnsorted);
nOut = pFrom->nRow + pWLoop->nOut;
maskNew = pFrom->maskLoop | pWLoop->maskSelf;
if( isOrdered<0 ){
isOrdered = wherePathSatisfiesOrderBy(pWInfo,
pWInfo->pOrderBy, pFrom, pWInfo->wctrlFlags,
iLoop, pWLoop, &revMask);
}else{
revMask = pFrom->revLoop;
}
if( isOrdered>=0 && isOrdered<nOrderBy ){
if( aSortCost[isOrdered]==0 ){
aSortCost[isOrdered] = whereSortingCost(
pWInfo, nRowEst, nOrderBy, isOrdered
);
}
/* TUNING: Add a small extra penalty (5) to sorting as an
( run in 1.951 second using v1.01-cache-2.11-cpan-71847e10f99 )