1 /* 2 ** 2013-11-12 3 ** 4 ** The author disclaims copyright to this source code. In place of 5 ** a legal notice, here is a blessing: 6 ** 7 ** May you do good and not evil. 8 ** May you find forgiveness for yourself and forgive others. 9 ** May you share freely, never taking more than you give. 10 ** 11 ************************************************************************* 12 ** 13 ** This file contains structure and macro definitions for the query 14 ** planner logic in "where.c". These definitions are broken out into 15 ** a separate source file for easier editing. 16 */ 17 18 /* 19 ** Trace output macros 20 */ 21 #if defined(SQLITE_TEST) || defined(SQLITE_DEBUG) 22 /***/ int sqlite3WhereTrace; 23 #endif 24 #if defined(SQLITE_DEBUG) \ 25 && (defined(SQLITE_TEST) || defined(SQLITE_ENABLE_WHERETRACE)) 26 # define WHERETRACE(K,X) if(sqlite3WhereTrace&(K)) sqlite3DebugPrintf X 27 # define WHERETRACE_ENABLED 1 28 #else 29 # define WHERETRACE(K,X) 30 #endif 31 32 /* Forward references 33 */ 34 typedef struct WhereClause WhereClause; 35 typedef struct WhereMaskSet WhereMaskSet; 36 typedef struct WhereOrInfo WhereOrInfo; 37 typedef struct WhereAndInfo WhereAndInfo; 38 typedef struct WhereLevel WhereLevel; 39 typedef struct WhereLoop WhereLoop; 40 typedef struct WherePath WherePath; 41 typedef struct WhereTerm WhereTerm; 42 typedef struct WhereLoopBuilder WhereLoopBuilder; 43 typedef struct WhereScan WhereScan; 44 typedef struct WhereOrCost WhereOrCost; 45 typedef struct WhereOrSet WhereOrSet; 46 47 /* 48 ** This object contains information needed to implement a single nested 49 ** loop in WHERE clause. 50 ** 51 ** Contrast this object with WhereLoop. This object describes the 52 ** implementation of the loop. WhereLoop describes the algorithm. 53 ** This object contains a pointer to the WhereLoop algorithm as one of 54 ** its elements. 55 ** 56 ** The WhereInfo object contains a single instance of this object for 57 ** each term in the FROM clause (which is to say, for each of the 58 ** nested loops as implemented). The order of WhereLevel objects determines 59 ** the loop nested order, with WhereInfo.a[0] being the outer loop and 60 ** WhereInfo.a[WhereInfo.nLevel-1] being the inner loop. 61 */ 62 struct WhereLevel { 63 int iLeftJoin; /* Memory cell used to implement LEFT OUTER JOIN */ 64 int iTabCur; /* The VDBE cursor used to access the table */ 65 int iIdxCur; /* The VDBE cursor used to access pIdx */ 66 int addrBrk; /* Jump here to break out of the loop */ 67 int addrNxt; /* Jump here to start the next IN combination */ 68 int addrSkip; /* Jump here for next iteration of skip-scan */ 69 int addrCont; /* Jump here to continue with the next loop cycle */ 70 int addrFirst; /* First instruction of interior of the loop */ 71 int addrBody; /* Beginning of the body of this loop */ 72 #ifndef SQLITE_LIKE_DOESNT_MATCH_BLOBS 73 u32 iLikeRepCntr; /* LIKE range processing counter register (times 2) */ 74 int addrLikeRep; /* LIKE range processing address */ 75 #endif 76 u8 iFrom; /* Which entry in the FROM clause */ 77 u8 op, p3, p5; /* Opcode, P3 & P5 of the opcode that ends the loop */ 78 int p1, p2; /* Operands of the opcode used to ends the loop */ 79 union { /* Information that depends on pWLoop->wsFlags */ 80 struct { 81 int nIn; /* Number of entries in aInLoop[] */ 82 struct InLoop { 83 int iCur; /* The VDBE cursor used by this IN operator */ 84 int addrInTop; /* Top of the IN loop */ 85 u8 eEndLoopOp; /* IN Loop terminator. OP_Next or OP_Prev */ 86 } *aInLoop; /* Information about each nested IN operator */ 87 } in; /* Used when pWLoop->wsFlags&WHERE_IN_ABLE */ 88 Index *pCovidx; /* Possible covering index for WHERE_MULTI_OR */ 89 } u; 90 struct WhereLoop *pWLoop; /* The selected WhereLoop object */ 91 Bitmask notReady; /* FROM entries not usable at this level */ 92 #ifdef SQLITE_ENABLE_STMT_SCANSTATUS 93 int addrVisit; /* Address at which row is visited */ 94 #endif 95 }; 96 97 /* 98 ** Each instance of this object represents an algorithm for evaluating one 99 ** term of a join. Every term of the FROM clause will have at least 100 ** one corresponding WhereLoop object (unless INDEXED BY constraints 101 ** prevent a query solution - which is an error) and many terms of the 102 ** FROM clause will have multiple WhereLoop objects, each describing a 103 ** potential way of implementing that FROM-clause term, together with 104 ** dependencies and cost estimates for using the chosen algorithm. 105 ** 106 ** Query planning consists of building up a collection of these WhereLoop 107 ** objects, then computing a particular sequence of WhereLoop objects, with 108 ** one WhereLoop object per FROM clause term, that satisfy all dependencies 109 ** and that minimize the overall cost. 110 */ 111 struct WhereLoop { 112 Bitmask prereq; /* Bitmask of other loops that must run first */ 113 Bitmask maskSelf; /* Bitmask identifying table iTab */ 114 #ifdef SQLITE_DEBUG 115 char cId; /* Symbolic ID of this loop for debugging use */ 116 #endif 117 u8 iTab; /* Position in FROM clause of table for this loop */ 118 u8 iSortIdx; /* Sorting index number. 0==None */ 119 LogEst rSetup; /* One-time setup cost (ex: create transient index) */ 120 LogEst rRun; /* Cost of running each loop */ 121 LogEst nOut; /* Estimated number of output rows */ 122 union { 123 struct { /* Information for internal btree tables */ 124 u16 nEq; /* Number of equality constraints */ 125 u16 nBtm; /* Size of BTM vector */ 126 u16 nTop; /* Size of TOP vector */ 127 u16 nIdxCol; /* Index column used for ORDER BY */ 128 Index *pIndex; /* Index used, or NULL */ 129 } btree; 130 struct { /* Information for virtual tables */ 131 int idxNum; /* Index number */ 132 u8 needFree; /* True if sqlite3_free(idxStr) is needed */ 133 i8 isOrdered; /* True if satisfies ORDER BY */ 134 u16 omitMask; /* Terms that may be omitted */ 135 char *idxStr; /* Index identifier string */ 136 } vtab; 137 } u; 138 u32 wsFlags; /* WHERE_* flags describing the plan */ 139 u16 nLTerm; /* Number of entries in aLTerm[] */ 140 u16 nSkip; /* Number of NULL aLTerm[] entries */ 141 /**** whereLoopXfer() copies fields above ***********************/ 142 # define WHERE_LOOP_XFER_SZ offsetof(WhereLoop,nLSlot) 143 u16 nLSlot; /* Number of slots allocated for aLTerm[] */ 144 WhereTerm **aLTerm; /* WhereTerms used */ 145 WhereLoop *pNextLoop; /* Next WhereLoop object in the WhereClause */ 146 WhereTerm *aLTermSpace[3]; /* Initial aLTerm[] space */ 147 }; 148 149 /* This object holds the prerequisites and the cost of running a 150 ** subquery on one operand of an OR operator in the WHERE clause. 151 ** See WhereOrSet for additional information 152 */ 153 struct WhereOrCost { 154 Bitmask prereq; /* Prerequisites */ 155 LogEst rRun; /* Cost of running this subquery */ 156 LogEst nOut; /* Number of outputs for this subquery */ 157 }; 158 159 /* The WhereOrSet object holds a set of possible WhereOrCosts that 160 ** correspond to the subquery(s) of OR-clause processing. Only the 161 ** best N_OR_COST elements are retained. 162 */ 163 #define N_OR_COST 3 164 struct WhereOrSet { 165 u16 n; /* Number of valid a[] entries */ 166 WhereOrCost a[N_OR_COST]; /* Set of best costs */ 167 }; 168 169 /* 170 ** Each instance of this object holds a sequence of WhereLoop objects 171 ** that implement some or all of a query plan. 172 ** 173 ** Think of each WhereLoop object as a node in a graph with arcs 174 ** showing dependencies and costs for travelling between nodes. (That is 175 ** not a completely accurate description because WhereLoop costs are a 176 ** vector, not a scalar, and because dependencies are many-to-one, not 177 ** one-to-one as are graph nodes. But it is a useful visualization aid.) 178 ** Then a WherePath object is a path through the graph that visits some 179 ** or all of the WhereLoop objects once. 180 ** 181 ** The "solver" works by creating the N best WherePath objects of length 182 ** 1. Then using those as a basis to compute the N best WherePath objects 183 ** of length 2. And so forth until the length of WherePaths equals the 184 ** number of nodes in the FROM clause. The best (lowest cost) WherePath 185 ** at the end is the chosen query plan. 186 */ 187 struct WherePath { 188 Bitmask maskLoop; /* Bitmask of all WhereLoop objects in this path */ 189 Bitmask revLoop; /* aLoop[]s that should be reversed for ORDER BY */ 190 LogEst nRow; /* Estimated number of rows generated by this path */ 191 LogEst rCost; /* Total cost of this path */ 192 LogEst rUnsorted; /* Total cost of this path ignoring sorting costs */ 193 i8 isOrdered; /* No. of ORDER BY terms satisfied. -1 for unknown */ 194 WhereLoop **aLoop; /* Array of WhereLoop objects implementing this path */ 195 }; 196 197 /* 198 ** The query generator uses an array of instances of this structure to 199 ** help it analyze the subexpressions of the WHERE clause. Each WHERE 200 ** clause subexpression is separated from the others by AND operators, 201 ** usually, or sometimes subexpressions separated by OR. 202 ** 203 ** All WhereTerms are collected into a single WhereClause structure. 204 ** The following identity holds: 205 ** 206 ** WhereTerm.pWC->a[WhereTerm.idx] == WhereTerm 207 ** 208 ** When a term is of the form: 209 ** 210 ** X <op> <expr> 211 ** 212 ** where X is a column name and <op> is one of certain operators, 213 ** then WhereTerm.leftCursor and WhereTerm.u.leftColumn record the 214 ** cursor number and column number for X. WhereTerm.eOperator records 215 ** the <op> using a bitmask encoding defined by WO_xxx below. The 216 ** use of a bitmask encoding for the operator allows us to search 217 ** quickly for terms that match any of several different operators. 218 ** 219 ** A WhereTerm might also be two or more subterms connected by OR: 220 ** 221 ** (t1.X <op> <expr>) OR (t1.Y <op> <expr>) OR .... 222 ** 223 ** In this second case, wtFlag has the TERM_ORINFO bit set and eOperator==WO_OR 224 ** and the WhereTerm.u.pOrInfo field points to auxiliary information that 225 ** is collected about the OR clause. 226 ** 227 ** If a term in the WHERE clause does not match either of the two previous 228 ** categories, then eOperator==0. The WhereTerm.pExpr field is still set 229 ** to the original subexpression content and wtFlags is set up appropriately 230 ** but no other fields in the WhereTerm object are meaningful. 231 ** 232 ** When eOperator!=0, prereqRight and prereqAll record sets of cursor numbers, 233 ** but they do so indirectly. A single WhereMaskSet structure translates 234 ** cursor number into bits and the translated bit is stored in the prereq 235 ** fields. The translation is used in order to maximize the number of 236 ** bits that will fit in a Bitmask. The VDBE cursor numbers might be 237 ** spread out over the non-negative integers. For example, the cursor 238 ** numbers might be 3, 8, 9, 10, 20, 23, 41, and 45. The WhereMaskSet 239 ** translates these sparse cursor numbers into consecutive integers 240 ** beginning with 0 in order to make the best possible use of the available 241 ** bits in the Bitmask. So, in the example above, the cursor numbers 242 ** would be mapped into integers 0 through 7. 243 ** 244 ** The number of terms in a join is limited by the number of bits 245 ** in prereqRight and prereqAll. The default is 64 bits, hence SQLite 246 ** is only able to process joins with 64 or fewer tables. 247 */ 248 struct WhereTerm { 249 Expr *pExpr; /* Pointer to the subexpression that is this term */ 250 WhereClause *pWC; /* The clause this term is part of */ 251 LogEst truthProb; /* Probability of truth for this expression */ 252 u16 wtFlags; /* TERM_xxx bit flags. See below */ 253 u16 eOperator; /* A WO_xx value describing <op> */ 254 u8 nChild; /* Number of children that must disable us */ 255 u8 eMatchOp; /* Op for vtab MATCH/LIKE/GLOB/REGEXP terms */ 256 int iParent; /* Disable pWC->a[iParent] when this term disabled */ 257 int leftCursor; /* Cursor number of X in "X <op> <expr>" */ 258 int iField; /* Field in (?,?,?) IN (SELECT...) vector */ 259 union { 260 int leftColumn; /* Column number of X in "X <op> <expr>" */ 261 WhereOrInfo *pOrInfo; /* Extra information if (eOperator & WO_OR)!=0 */ 262 WhereAndInfo *pAndInfo; /* Extra information if (eOperator& WO_AND)!=0 */ 263 } u; 264 Bitmask prereqRight; /* Bitmask of tables used by pExpr->pRight */ 265 Bitmask prereqAll; /* Bitmask of tables referenced by pExpr */ 266 }; 267 268 /* 269 ** Allowed values of WhereTerm.wtFlags 270 */ 271 #define TERM_DYNAMIC 0x01 /* Need to call sqlite3ExprDelete(db, pExpr) */ 272 #define TERM_VIRTUAL 0x02 /* Added by the optimizer. Do not code */ 273 #define TERM_CODED 0x04 /* This term is already coded */ 274 #define TERM_COPIED 0x08 /* Has a child */ 275 #define TERM_ORINFO 0x10 /* Need to free the WhereTerm.u.pOrInfo object */ 276 #define TERM_ANDINFO 0x20 /* Need to free the WhereTerm.u.pAndInfo obj */ 277 #define TERM_OR_OK 0x40 /* Used during OR-clause processing */ 278 #ifdef SQLITE_ENABLE_STAT3_OR_STAT4 279 # define TERM_VNULL 0x80 /* Manufactured x>NULL or x<=NULL term */ 280 #else 281 # define TERM_VNULL 0x00 /* Disabled if not using stat3 */ 282 #endif 283 #define TERM_LIKEOPT 0x100 /* Virtual terms from the LIKE optimization */ 284 #define TERM_LIKECOND 0x200 /* Conditionally this LIKE operator term */ 285 #define TERM_LIKE 0x400 /* The original LIKE operator */ 286 #define TERM_IS 0x800 /* Term.pExpr is an IS operator */ 287 #define TERM_VARSELECT 0x1000 /* Term.pExpr contains a correlated sub-query */ 288 289 /* 290 ** An instance of the WhereScan object is used as an iterator for locating 291 ** terms in the WHERE clause that are useful to the query planner. 292 */ 293 struct WhereScan { 294 WhereClause *pOrigWC; /* Original, innermost WhereClause */ 295 WhereClause *pWC; /* WhereClause currently being scanned */ 296 const char *zCollName; /* Required collating sequence, if not NULL */ 297 Expr *pIdxExpr; /* Search for this index expression */ 298 char idxaff; /* Must match this affinity, if zCollName!=NULL */ 299 unsigned char nEquiv; /* Number of entries in aEquiv[] */ 300 unsigned char iEquiv; /* Next unused slot in aEquiv[] */ 301 u32 opMask; /* Acceptable operators */ 302 int k; /* Resume scanning at this->pWC->a[this->k] */ 303 int aiCur[11]; /* Cursors in the equivalence class */ 304 i16 aiColumn[11]; /* Corresponding column number in the eq-class */ 305 }; 306 307 /* 308 ** An instance of the following structure holds all information about a 309 ** WHERE clause. Mostly this is a container for one or more WhereTerms. 310 ** 311 ** Explanation of pOuter: For a WHERE clause of the form 312 ** 313 ** a AND ((b AND c) OR (d AND e)) AND f 314 ** 315 ** There are separate WhereClause objects for the whole clause and for 316 ** the subclauses "(b AND c)" and "(d AND e)". The pOuter field of the 317 ** subclauses points to the WhereClause object for the whole clause. 318 */ 319 struct WhereClause { 320 WhereInfo *pWInfo; /* WHERE clause processing context */ 321 WhereClause *pOuter; /* Outer conjunction */ 322 u8 op; /* Split operator. TK_AND or TK_OR */ 323 int nTerm; /* Number of terms */ 324 int nSlot; /* Number of entries in a[] */ 325 WhereTerm *a; /* Each a[] describes a term of the WHERE cluase */ 326 #if defined(SQLITE_SMALL_STACK) 327 WhereTerm aStatic[1]; /* Initial static space for a[] */ 328 #else 329 WhereTerm aStatic[8]; /* Initial static space for a[] */ 330 #endif 331 }; 332 333 /* 334 ** A WhereTerm with eOperator==WO_OR has its u.pOrInfo pointer set to 335 ** a dynamically allocated instance of the following structure. 336 */ 337 struct WhereOrInfo { 338 WhereClause wc; /* Decomposition into subterms */ 339 Bitmask indexable; /* Bitmask of all indexable tables in the clause */ 340 }; 341 342 /* 343 ** A WhereTerm with eOperator==WO_AND has its u.pAndInfo pointer set to 344 ** a dynamically allocated instance of the following structure. 345 */ 346 struct WhereAndInfo { 347 WhereClause wc; /* The subexpression broken out */ 348 }; 349 350 /* 351 ** An instance of the following structure keeps track of a mapping 352 ** between VDBE cursor numbers and bits of the bitmasks in WhereTerm. 353 ** 354 ** The VDBE cursor numbers are small integers contained in 355 ** SrcList_item.iCursor and Expr.iTable fields. For any given WHERE 356 ** clause, the cursor numbers might not begin with 0 and they might 357 ** contain gaps in the numbering sequence. But we want to make maximum 358 ** use of the bits in our bitmasks. This structure provides a mapping 359 ** from the sparse cursor numbers into consecutive integers beginning 360 ** with 0. 361 ** 362 ** If WhereMaskSet.ix[A]==B it means that The A-th bit of a Bitmask 363 ** corresponds VDBE cursor number B. The A-th bit of a bitmask is 1<<A. 364 ** 365 ** For example, if the WHERE clause expression used these VDBE 366 ** cursors: 4, 5, 8, 29, 57, 73. Then the WhereMaskSet structure 367 ** would map those cursor numbers into bits 0 through 5. 368 ** 369 ** Note that the mapping is not necessarily ordered. In the example 370 ** above, the mapping might go like this: 4->3, 5->1, 8->2, 29->0, 371 ** 57->5, 73->4. Or one of 719 other combinations might be used. It 372 ** does not really matter. What is important is that sparse cursor 373 ** numbers all get mapped into bit numbers that begin with 0 and contain 374 ** no gaps. 375 */ 376 struct WhereMaskSet { 377 int bVarSelect; /* Used by sqlite3WhereExprUsage() */ 378 int n; /* Number of assigned cursor values */ 379 int ix[BMS]; /* Cursor assigned to each bit */ 380 }; 381 382 /* 383 ** Initialize a WhereMaskSet object 384 */ 385 #define initMaskSet(P) (P)->n=0 386 387 /* 388 ** This object is a convenience wrapper holding all information needed 389 ** to construct WhereLoop objects for a particular query. 390 */ 391 struct WhereLoopBuilder { 392 WhereInfo *pWInfo; /* Information about this WHERE */ 393 WhereClause *pWC; /* WHERE clause terms */ 394 ExprList *pOrderBy; /* ORDER BY clause */ 395 WhereLoop *pNew; /* Template WhereLoop */ 396 WhereOrSet *pOrSet; /* Record best loops here, if not NULL */ 397 #ifdef SQLITE_ENABLE_STAT3_OR_STAT4 398 UnpackedRecord *pRec; /* Probe for stat4 (if required) */ 399 int nRecValid; /* Number of valid fields currently in pRec */ 400 #endif 401 unsigned int bldFlags; /* SQLITE_BLDF_* flags */ 402 }; 403 404 /* Allowed values for WhereLoopBuider.bldFlags */ 405 #define SQLITE_BLDF_INDEXED 0x0001 /* An index is used */ 406 #define SQLITE_BLDF_UNIQUE 0x0002 /* All keys of a UNIQUE index used */ 407 408 /* 409 ** The WHERE clause processing routine has two halves. The 410 ** first part does the start of the WHERE loop and the second 411 ** half does the tail of the WHERE loop. An instance of 412 ** this structure is returned by the first half and passed 413 ** into the second half to give some continuity. 414 ** 415 ** An instance of this object holds the complete state of the query 416 ** planner. 417 */ 418 struct WhereInfo { 419 Parse *pParse; /* Parsing and code generating context */ 420 SrcList *pTabList; /* List of tables in the join */ 421 ExprList *pOrderBy; /* The ORDER BY clause or NULL */ 422 ExprList *pResultSet; /* Result set of the query */ 423 Expr *pWhere; /* The complete WHERE clause */ 424 LogEst iLimit; /* LIMIT if wctrlFlags has WHERE_USE_LIMIT */ 425 int aiCurOnePass[2]; /* OP_OpenWrite cursors for the ONEPASS opt */ 426 int iContinue; /* Jump here to continue with next record */ 427 int iBreak; /* Jump here to break out of the loop */ 428 int savedNQueryLoop; /* pParse->nQueryLoop outside the WHERE loop */ 429 u16 wctrlFlags; /* Flags originally passed to sqlite3WhereBegin() */ 430 u8 nLevel; /* Number of nested loop */ 431 i8 nOBSat; /* Number of ORDER BY terms satisfied by indices */ 432 u8 sorted; /* True if really sorted (not just grouped) */ 433 u8 eOnePass; /* ONEPASS_OFF, or _SINGLE, or _MULTI */ 434 u8 untestedTerms; /* Not all WHERE terms resolved by outer loop */ 435 u8 eDistinct; /* One of the WHERE_DISTINCT_* values */ 436 u8 bOrderedInnerLoop; /* True if only the inner-most loop is ordered */ 437 int iTop; /* The very beginning of the WHERE loop */ 438 WhereLoop *pLoops; /* List of all WhereLoop objects */ 439 Bitmask revMask; /* Mask of ORDER BY terms that need reversing */ 440 LogEst nRowOut; /* Estimated number of output rows */ 441 WhereClause sWC; /* Decomposition of the WHERE clause */ 442 WhereMaskSet sMaskSet; /* Map cursor numbers to bitmasks */ 443 WhereLevel a[1]; /* Information about each nest loop in WHERE */ 444 }; 445 446 /* 447 ** Private interfaces - callable only by other where.c routines. 448 ** 449 ** where.c: 450 */ 451 Bitmask sqlite3WhereGetMask(WhereMaskSet*,int); 452 #ifdef WHERETRACE_ENABLED 453 void sqlite3WhereClausePrint(WhereClause *pWC); 454 #endif 455 WhereTerm *sqlite3WhereFindTerm( 456 WhereClause *pWC, /* The WHERE clause to be searched */ 457 int iCur, /* Cursor number of LHS */ 458 int iColumn, /* Column number of LHS */ 459 Bitmask notReady, /* RHS must not overlap with this mask */ 460 u32 op, /* Mask of WO_xx values describing operator */ 461 Index *pIdx /* Must be compatible with this index, if not NULL */ 462 ); 463 464 /* wherecode.c: */ 465 #ifndef SQLITE_OMIT_EXPLAIN 466 int sqlite3WhereExplainOneScan( 467 Parse *pParse, /* Parse context */ 468 SrcList *pTabList, /* Table list this loop refers to */ 469 WhereLevel *pLevel, /* Scan to write OP_Explain opcode for */ 470 int iLevel, /* Value for "level" column of output */ 471 int iFrom, /* Value for "from" column of output */ 472 u16 wctrlFlags /* Flags passed to sqlite3WhereBegin() */ 473 ); 474 #else 475 # define sqlite3WhereExplainOneScan(u,v,w,x,y,z) 0 476 #endif /* SQLITE_OMIT_EXPLAIN */ 477 #ifdef SQLITE_ENABLE_STMT_SCANSTATUS 478 void sqlite3WhereAddScanStatus( 479 Vdbe *v, /* Vdbe to add scanstatus entry to */ 480 SrcList *pSrclist, /* FROM clause pLvl reads data from */ 481 WhereLevel *pLvl, /* Level to add scanstatus() entry for */ 482 int addrExplain /* Address of OP_Explain (or 0) */ 483 ); 484 #else 485 # define sqlite3WhereAddScanStatus(a, b, c, d) ((void)d) 486 #endif 487 Bitmask sqlite3WhereCodeOneLoopStart( 488 WhereInfo *pWInfo, /* Complete information about the WHERE clause */ 489 int iLevel, /* Which level of pWInfo->a[] should be coded */ 490 Bitmask notReady /* Which tables are currently available */ 491 ); 492 493 /* whereexpr.c: */ 494 void sqlite3WhereClauseInit(WhereClause*,WhereInfo*); 495 void sqlite3WhereClauseClear(WhereClause*); 496 void sqlite3WhereSplit(WhereClause*,Expr*,u8); 497 Bitmask sqlite3WhereExprUsage(WhereMaskSet*, Expr*); 498 Bitmask sqlite3WhereExprListUsage(WhereMaskSet*, ExprList*); 499 void sqlite3WhereExprAnalyze(SrcList*, WhereClause*); 500 void sqlite3WhereTabFuncArgs(Parse*, struct SrcList_item*, WhereClause*); 501 502 503 504 505 506 /* 507 ** Bitmasks for the operators on WhereTerm objects. These are all 508 ** operators that are of interest to the query planner. An 509 ** OR-ed combination of these values can be used when searching for 510 ** particular WhereTerms within a WhereClause. 511 ** 512 ** Value constraints: 513 ** WO_EQ == SQLITE_INDEX_CONSTRAINT_EQ 514 ** WO_LT == SQLITE_INDEX_CONSTRAINT_LT 515 ** WO_LE == SQLITE_INDEX_CONSTRAINT_LE 516 ** WO_GT == SQLITE_INDEX_CONSTRAINT_GT 517 ** WO_GE == SQLITE_INDEX_CONSTRAINT_GE 518 */ 519 #define WO_IN 0x0001 520 #define WO_EQ 0x0002 521 #define WO_LT (WO_EQ<<(TK_LT-TK_EQ)) 522 #define WO_LE (WO_EQ<<(TK_LE-TK_EQ)) 523 #define WO_GT (WO_EQ<<(TK_GT-TK_EQ)) 524 #define WO_GE (WO_EQ<<(TK_GE-TK_EQ)) 525 #define WO_AUX 0x0040 /* Op useful to virtual tables only */ 526 #define WO_IS 0x0080 527 #define WO_ISNULL 0x0100 528 #define WO_OR 0x0200 /* Two or more OR-connected terms */ 529 #define WO_AND 0x0400 /* Two or more AND-connected terms */ 530 #define WO_EQUIV 0x0800 /* Of the form A==B, both columns */ 531 #define WO_NOOP 0x1000 /* This term does not restrict search space */ 532 533 #define WO_ALL 0x1fff /* Mask of all possible WO_* values */ 534 #define WO_SINGLE 0x01ff /* Mask of all non-compound WO_* values */ 535 536 /* 537 ** These are definitions of bits in the WhereLoop.wsFlags field. 538 ** The particular combination of bits in each WhereLoop help to 539 ** determine the algorithm that WhereLoop represents. 540 */ 541 #define WHERE_COLUMN_EQ 0x00000001 /* x=EXPR */ 542 #define WHERE_COLUMN_RANGE 0x00000002 /* x<EXPR and/or x>EXPR */ 543 #define WHERE_COLUMN_IN 0x00000004 /* x IN (...) */ 544 #define WHERE_COLUMN_NULL 0x00000008 /* x IS NULL */ 545 #define WHERE_CONSTRAINT 0x0000000f /* Any of the WHERE_COLUMN_xxx values */ 546 #define WHERE_TOP_LIMIT 0x00000010 /* x<EXPR or x<=EXPR constraint */ 547 #define WHERE_BTM_LIMIT 0x00000020 /* x>EXPR or x>=EXPR constraint */ 548 #define WHERE_BOTH_LIMIT 0x00000030 /* Both x>EXPR and x<EXPR */ 549 #define WHERE_IDX_ONLY 0x00000040 /* Use index only - omit table */ 550 #define WHERE_IPK 0x00000100 /* x is the INTEGER PRIMARY KEY */ 551 #define WHERE_INDEXED 0x00000200 /* WhereLoop.u.btree.pIndex is valid */ 552 #define WHERE_VIRTUALTABLE 0x00000400 /* WhereLoop.u.vtab is valid */ 553 #define WHERE_IN_ABLE 0x00000800 /* Able to support an IN operator */ 554 #define WHERE_ONEROW 0x00001000 /* Selects no more than one row */ 555 #define WHERE_MULTI_OR 0x00002000 /* OR using multiple indices */ 556 #define WHERE_AUTO_INDEX 0x00004000 /* Uses an ephemeral index */ 557 #define WHERE_SKIPSCAN 0x00008000 /* Uses the skip-scan algorithm */ 558 #define WHERE_UNQ_WANTED 0x00010000 /* WHERE_ONEROW would have been helpful*/ 559 #define WHERE_PARTIALIDX 0x00020000 /* The automatic index is partial */ 560