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 /***/ extern 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 int iBase; /* Base register of multi-key index record */ 86 int nPrefix; /* Number of prior entires in the key */ 87 u8 eEndLoopOp; /* IN Loop terminator. OP_Next or OP_Prev */ 88 } *aInLoop; /* Information about each nested IN operator */ 89 } in; /* Used when pWLoop->wsFlags&WHERE_IN_ABLE */ 90 Index *pCovidx; /* Possible covering index for WHERE_MULTI_OR */ 91 } u; 92 struct WhereLoop *pWLoop; /* The selected WhereLoop object */ 93 Bitmask notReady; /* FROM entries not usable at this level */ 94 #ifdef SQLITE_ENABLE_STMT_SCANSTATUS 95 int addrVisit; /* Address at which row is visited */ 96 #endif 97 }; 98 99 /* 100 ** Each instance of this object represents an algorithm for evaluating one 101 ** term of a join. Every term of the FROM clause will have at least 102 ** one corresponding WhereLoop object (unless INDEXED BY constraints 103 ** prevent a query solution - which is an error) and many terms of the 104 ** FROM clause will have multiple WhereLoop objects, each describing a 105 ** potential way of implementing that FROM-clause term, together with 106 ** dependencies and cost estimates for using the chosen algorithm. 107 ** 108 ** Query planning consists of building up a collection of these WhereLoop 109 ** objects, then computing a particular sequence of WhereLoop objects, with 110 ** one WhereLoop object per FROM clause term, that satisfy all dependencies 111 ** and that minimize the overall cost. 112 */ 113 struct WhereLoop { 114 Bitmask prereq; /* Bitmask of other loops that must run first */ 115 Bitmask maskSelf; /* Bitmask identifying table iTab */ 116 #ifdef SQLITE_DEBUG 117 char cId; /* Symbolic ID of this loop for debugging use */ 118 #endif 119 u8 iTab; /* Position in FROM clause of table for this loop */ 120 u8 iSortIdx; /* Sorting index number. 0==None */ 121 LogEst rSetup; /* One-time setup cost (ex: create transient index) */ 122 LogEst rRun; /* Cost of running each loop */ 123 LogEst nOut; /* Estimated number of output rows */ 124 union { 125 struct { /* Information for internal btree tables */ 126 u16 nEq; /* Number of equality constraints */ 127 u16 nBtm; /* Size of BTM vector */ 128 u16 nTop; /* Size of TOP vector */ 129 u16 nIdxCol; /* Index column used for ORDER BY */ 130 Index *pIndex; /* Index used, or NULL */ 131 } btree; 132 struct { /* Information for virtual tables */ 133 int idxNum; /* Index number */ 134 u8 needFree; /* True if sqlite3_free(idxStr) is needed */ 135 i8 isOrdered; /* True if satisfies ORDER BY */ 136 u16 omitMask; /* Terms that may be omitted */ 137 char *idxStr; /* Index identifier string */ 138 } vtab; 139 } u; 140 u32 wsFlags; /* WHERE_* flags describing the plan */ 141 u16 nLTerm; /* Number of entries in aLTerm[] */ 142 u16 nSkip; /* Number of NULL aLTerm[] entries */ 143 /**** whereLoopXfer() copies fields above ***********************/ 144 # define WHERE_LOOP_XFER_SZ offsetof(WhereLoop,nLSlot) 145 u16 nLSlot; /* Number of slots allocated for aLTerm[] */ 146 WhereTerm **aLTerm; /* WhereTerms used */ 147 WhereLoop *pNextLoop; /* Next WhereLoop object in the WhereClause */ 148 WhereTerm *aLTermSpace[3]; /* Initial aLTerm[] space */ 149 }; 150 151 /* This object holds the prerequisites and the cost of running a 152 ** subquery on one operand of an OR operator in the WHERE clause. 153 ** See WhereOrSet for additional information 154 */ 155 struct WhereOrCost { 156 Bitmask prereq; /* Prerequisites */ 157 LogEst rRun; /* Cost of running this subquery */ 158 LogEst nOut; /* Number of outputs for this subquery */ 159 }; 160 161 /* The WhereOrSet object holds a set of possible WhereOrCosts that 162 ** correspond to the subquery(s) of OR-clause processing. Only the 163 ** best N_OR_COST elements are retained. 164 */ 165 #define N_OR_COST 3 166 struct WhereOrSet { 167 u16 n; /* Number of valid a[] entries */ 168 WhereOrCost a[N_OR_COST]; /* Set of best costs */ 169 }; 170 171 /* 172 ** Each instance of this object holds a sequence of WhereLoop objects 173 ** that implement some or all of a query plan. 174 ** 175 ** Think of each WhereLoop object as a node in a graph with arcs 176 ** showing dependencies and costs for travelling between nodes. (That is 177 ** not a completely accurate description because WhereLoop costs are a 178 ** vector, not a scalar, and because dependencies are many-to-one, not 179 ** one-to-one as are graph nodes. But it is a useful visualization aid.) 180 ** Then a WherePath object is a path through the graph that visits some 181 ** or all of the WhereLoop objects once. 182 ** 183 ** The "solver" works by creating the N best WherePath objects of length 184 ** 1. Then using those as a basis to compute the N best WherePath objects 185 ** of length 2. And so forth until the length of WherePaths equals the 186 ** number of nodes in the FROM clause. The best (lowest cost) WherePath 187 ** at the end is the chosen query plan. 188 */ 189 struct WherePath { 190 Bitmask maskLoop; /* Bitmask of all WhereLoop objects in this path */ 191 Bitmask revLoop; /* aLoop[]s that should be reversed for ORDER BY */ 192 LogEst nRow; /* Estimated number of rows generated by this path */ 193 LogEst rCost; /* Total cost of this path */ 194 LogEst rUnsorted; /* Total cost of this path ignoring sorting costs */ 195 i8 isOrdered; /* No. of ORDER BY terms satisfied. -1 for unknown */ 196 WhereLoop **aLoop; /* Array of WhereLoop objects implementing this path */ 197 }; 198 199 /* 200 ** The query generator uses an array of instances of this structure to 201 ** help it analyze the subexpressions of the WHERE clause. Each WHERE 202 ** clause subexpression is separated from the others by AND operators, 203 ** usually, or sometimes subexpressions separated by OR. 204 ** 205 ** All WhereTerms are collected into a single WhereClause structure. 206 ** The following identity holds: 207 ** 208 ** WhereTerm.pWC->a[WhereTerm.idx] == WhereTerm 209 ** 210 ** When a term is of the form: 211 ** 212 ** X <op> <expr> 213 ** 214 ** where X is a column name and <op> is one of certain operators, 215 ** then WhereTerm.leftCursor and WhereTerm.u.leftColumn record the 216 ** cursor number and column number for X. WhereTerm.eOperator records 217 ** the <op> using a bitmask encoding defined by WO_xxx below. The 218 ** use of a bitmask encoding for the operator allows us to search 219 ** quickly for terms that match any of several different operators. 220 ** 221 ** A WhereTerm might also be two or more subterms connected by OR: 222 ** 223 ** (t1.X <op> <expr>) OR (t1.Y <op> <expr>) OR .... 224 ** 225 ** In this second case, wtFlag has the TERM_ORINFO bit set and eOperator==WO_OR 226 ** and the WhereTerm.u.pOrInfo field points to auxiliary information that 227 ** is collected about the OR clause. 228 ** 229 ** If a term in the WHERE clause does not match either of the two previous 230 ** categories, then eOperator==0. The WhereTerm.pExpr field is still set 231 ** to the original subexpression content and wtFlags is set up appropriately 232 ** but no other fields in the WhereTerm object are meaningful. 233 ** 234 ** When eOperator!=0, prereqRight and prereqAll record sets of cursor numbers, 235 ** but they do so indirectly. A single WhereMaskSet structure translates 236 ** cursor number into bits and the translated bit is stored in the prereq 237 ** fields. The translation is used in order to maximize the number of 238 ** bits that will fit in a Bitmask. The VDBE cursor numbers might be 239 ** spread out over the non-negative integers. For example, the cursor 240 ** numbers might be 3, 8, 9, 10, 20, 23, 41, and 45. The WhereMaskSet 241 ** translates these sparse cursor numbers into consecutive integers 242 ** beginning with 0 in order to make the best possible use of the available 243 ** bits in the Bitmask. So, in the example above, the cursor numbers 244 ** would be mapped into integers 0 through 7. 245 ** 246 ** The number of terms in a join is limited by the number of bits 247 ** in prereqRight and prereqAll. The default is 64 bits, hence SQLite 248 ** is only able to process joins with 64 or fewer tables. 249 */ 250 struct WhereTerm { 251 Expr *pExpr; /* Pointer to the subexpression that is this term */ 252 WhereClause *pWC; /* The clause this term is part of */ 253 LogEst truthProb; /* Probability of truth for this expression */ 254 u16 wtFlags; /* TERM_xxx bit flags. See below */ 255 u16 eOperator; /* A WO_xx value describing <op> */ 256 u8 nChild; /* Number of children that must disable us */ 257 u8 eMatchOp; /* Op for vtab MATCH/LIKE/GLOB/REGEXP terms */ 258 int iParent; /* Disable pWC->a[iParent] when this term disabled */ 259 int leftCursor; /* Cursor number of X in "X <op> <expr>" */ 260 int iField; /* Field in (?,?,?) IN (SELECT...) vector */ 261 union { 262 int leftColumn; /* Column number of X in "X <op> <expr>" */ 263 WhereOrInfo *pOrInfo; /* Extra information if (eOperator & WO_OR)!=0 */ 264 WhereAndInfo *pAndInfo; /* Extra information if (eOperator& WO_AND)!=0 */ 265 } u; 266 Bitmask prereqRight; /* Bitmask of tables used by pExpr->pRight */ 267 Bitmask prereqAll; /* Bitmask of tables referenced by pExpr */ 268 }; 269 270 /* 271 ** Allowed values of WhereTerm.wtFlags 272 */ 273 #define TERM_DYNAMIC 0x01 /* Need to call sqlite3ExprDelete(db, pExpr) */ 274 #define TERM_VIRTUAL 0x02 /* Added by the optimizer. Do not code */ 275 #define TERM_CODED 0x04 /* This term is already coded */ 276 #define TERM_COPIED 0x08 /* Has a child */ 277 #define TERM_ORINFO 0x10 /* Need to free the WhereTerm.u.pOrInfo object */ 278 #define TERM_ANDINFO 0x20 /* Need to free the WhereTerm.u.pAndInfo obj */ 279 #define TERM_OR_OK 0x40 /* Used during OR-clause processing */ 280 #ifdef SQLITE_ENABLE_STAT3_OR_STAT4 281 # define TERM_VNULL 0x80 /* Manufactured x>NULL or x<=NULL term */ 282 #else 283 # define TERM_VNULL 0x00 /* Disabled if not using stat3 */ 284 #endif 285 #define TERM_LIKEOPT 0x100 /* Virtual terms from the LIKE optimization */ 286 #define TERM_LIKECOND 0x200 /* Conditionally this LIKE operator term */ 287 #define TERM_LIKE 0x400 /* The original LIKE operator */ 288 #define TERM_IS 0x800 /* Term.pExpr is an IS operator */ 289 #define TERM_VARSELECT 0x1000 /* Term.pExpr contains a correlated sub-query */ 290 291 /* 292 ** An instance of the WhereScan object is used as an iterator for locating 293 ** terms in the WHERE clause that are useful to the query planner. 294 */ 295 struct WhereScan { 296 WhereClause *pOrigWC; /* Original, innermost WhereClause */ 297 WhereClause *pWC; /* WhereClause currently being scanned */ 298 const char *zCollName; /* Required collating sequence, if not NULL */ 299 Expr *pIdxExpr; /* Search for this index expression */ 300 char idxaff; /* Must match this affinity, if zCollName!=NULL */ 301 unsigned char nEquiv; /* Number of entries in aEquiv[] */ 302 unsigned char iEquiv; /* Next unused slot in aEquiv[] */ 303 u32 opMask; /* Acceptable operators */ 304 int k; /* Resume scanning at this->pWC->a[this->k] */ 305 int aiCur[11]; /* Cursors in the equivalence class */ 306 i16 aiColumn[11]; /* Corresponding column number in the eq-class */ 307 }; 308 309 /* 310 ** An instance of the following structure holds all information about a 311 ** WHERE clause. Mostly this is a container for one or more WhereTerms. 312 ** 313 ** Explanation of pOuter: For a WHERE clause of the form 314 ** 315 ** a AND ((b AND c) OR (d AND e)) AND f 316 ** 317 ** There are separate WhereClause objects for the whole clause and for 318 ** the subclauses "(b AND c)" and "(d AND e)". The pOuter field of the 319 ** subclauses points to the WhereClause object for the whole clause. 320 */ 321 struct WhereClause { 322 WhereInfo *pWInfo; /* WHERE clause processing context */ 323 WhereClause *pOuter; /* Outer conjunction */ 324 u8 op; /* Split operator. TK_AND or TK_OR */ 325 u8 hasOr; /* True if any a[].eOperator is WO_OR */ 326 int nTerm; /* Number of terms */ 327 int nSlot; /* Number of entries in a[] */ 328 WhereTerm *a; /* Each a[] describes a term of the WHERE cluase */ 329 #if defined(SQLITE_SMALL_STACK) 330 WhereTerm aStatic[1]; /* Initial static space for a[] */ 331 #else 332 WhereTerm aStatic[8]; /* Initial static space for a[] */ 333 #endif 334 }; 335 336 /* 337 ** A WhereTerm with eOperator==WO_OR has its u.pOrInfo pointer set to 338 ** a dynamically allocated instance of the following structure. 339 */ 340 struct WhereOrInfo { 341 WhereClause wc; /* Decomposition into subterms */ 342 Bitmask indexable; /* Bitmask of all indexable tables in the clause */ 343 }; 344 345 /* 346 ** A WhereTerm with eOperator==WO_AND has its u.pAndInfo pointer set to 347 ** a dynamically allocated instance of the following structure. 348 */ 349 struct WhereAndInfo { 350 WhereClause wc; /* The subexpression broken out */ 351 }; 352 353 /* 354 ** An instance of the following structure keeps track of a mapping 355 ** between VDBE cursor numbers and bits of the bitmasks in WhereTerm. 356 ** 357 ** The VDBE cursor numbers are small integers contained in 358 ** SrcList_item.iCursor and Expr.iTable fields. For any given WHERE 359 ** clause, the cursor numbers might not begin with 0 and they might 360 ** contain gaps in the numbering sequence. But we want to make maximum 361 ** use of the bits in our bitmasks. This structure provides a mapping 362 ** from the sparse cursor numbers into consecutive integers beginning 363 ** with 0. 364 ** 365 ** If WhereMaskSet.ix[A]==B it means that The A-th bit of a Bitmask 366 ** corresponds VDBE cursor number B. The A-th bit of a bitmask is 1<<A. 367 ** 368 ** For example, if the WHERE clause expression used these VDBE 369 ** cursors: 4, 5, 8, 29, 57, 73. Then the WhereMaskSet structure 370 ** would map those cursor numbers into bits 0 through 5. 371 ** 372 ** Note that the mapping is not necessarily ordered. In the example 373 ** above, the mapping might go like this: 4->3, 5->1, 8->2, 29->0, 374 ** 57->5, 73->4. Or one of 719 other combinations might be used. It 375 ** does not really matter. What is important is that sparse cursor 376 ** numbers all get mapped into bit numbers that begin with 0 and contain 377 ** no gaps. 378 */ 379 struct WhereMaskSet { 380 int bVarSelect; /* Used by sqlite3WhereExprUsage() */ 381 int n; /* Number of assigned cursor values */ 382 int ix[BMS]; /* Cursor assigned to each bit */ 383 }; 384 385 /* 386 ** Initialize a WhereMaskSet object 387 */ 388 #define initMaskSet(P) (P)->n=0 389 390 /* 391 ** This object is a convenience wrapper holding all information needed 392 ** to construct WhereLoop objects for a particular query. 393 */ 394 struct WhereLoopBuilder { 395 WhereInfo *pWInfo; /* Information about this WHERE */ 396 WhereClause *pWC; /* WHERE clause terms */ 397 ExprList *pOrderBy; /* ORDER BY clause */ 398 WhereLoop *pNew; /* Template WhereLoop */ 399 WhereOrSet *pOrSet; /* Record best loops here, if not NULL */ 400 #ifdef SQLITE_ENABLE_STAT3_OR_STAT4 401 UnpackedRecord *pRec; /* Probe for stat4 (if required) */ 402 int nRecValid; /* Number of valid fields currently in pRec */ 403 #endif 404 unsigned int bldFlags; /* SQLITE_BLDF_* flags */ 405 unsigned int iPlanLimit; /* Search limiter */ 406 }; 407 408 /* Allowed values for WhereLoopBuider.bldFlags */ 409 #define SQLITE_BLDF_INDEXED 0x0001 /* An index is used */ 410 #define SQLITE_BLDF_UNIQUE 0x0002 /* All keys of a UNIQUE index used */ 411 412 /* The WhereLoopBuilder.iPlanLimit is used to limit the number of 413 ** index+constraint combinations the query planner will consider for a 414 ** particular query. If this parameter is unlimited, then certain 415 ** pathological queries can spend excess time in the sqlite3WhereBegin() 416 ** routine. The limit is high enough that is should not impact real-world 417 ** queries. 418 ** 419 ** SQLITE_QUERY_PLANNER_LIMIT is the baseline limit. The limit is 420 ** increased by SQLITE_QUERY_PLANNER_LIMIT_INCR before each term of the FROM 421 ** clause is processed, so that every table in a join is guaranteed to be 422 ** able to propose a some index+constraint combinations even if the initial 423 ** baseline limit was exhausted by prior tables of the join. 424 */ 425 #ifndef SQLITE_QUERY_PLANNER_LIMIT 426 # define SQLITE_QUERY_PLANNER_LIMIT 20000 427 #endif 428 #ifndef SQLITE_QUERY_PLANNER_LIMIT_INCR 429 # define SQLITE_QUERY_PLANNER_LIMIT_INCR 1000 430 #endif 431 432 /* 433 ** The WHERE clause processing routine has two halves. The 434 ** first part does the start of the WHERE loop and the second 435 ** half does the tail of the WHERE loop. An instance of 436 ** this structure is returned by the first half and passed 437 ** into the second half to give some continuity. 438 ** 439 ** An instance of this object holds the complete state of the query 440 ** planner. 441 */ 442 struct WhereInfo { 443 Parse *pParse; /* Parsing and code generating context */ 444 SrcList *pTabList; /* List of tables in the join */ 445 ExprList *pOrderBy; /* The ORDER BY clause or NULL */ 446 ExprList *pResultSet; /* Result set of the query */ 447 Expr *pWhere; /* The complete WHERE clause */ 448 LogEst iLimit; /* LIMIT if wctrlFlags has WHERE_USE_LIMIT */ 449 int aiCurOnePass[2]; /* OP_OpenWrite cursors for the ONEPASS opt */ 450 int iContinue; /* Jump here to continue with next record */ 451 int iBreak; /* Jump here to break out of the loop */ 452 int savedNQueryLoop; /* pParse->nQueryLoop outside the WHERE loop */ 453 u16 wctrlFlags; /* Flags originally passed to sqlite3WhereBegin() */ 454 u8 nLevel; /* Number of nested loop */ 455 i8 nOBSat; /* Number of ORDER BY terms satisfied by indices */ 456 u8 sorted; /* True if really sorted (not just grouped) */ 457 u8 eOnePass; /* ONEPASS_OFF, or _SINGLE, or _MULTI */ 458 u8 untestedTerms; /* Not all WHERE terms resolved by outer loop */ 459 u8 eDistinct; /* One of the WHERE_DISTINCT_* values */ 460 u8 bOrderedInnerLoop; /* True if only the inner-most loop is ordered */ 461 int iTop; /* The very beginning of the WHERE loop */ 462 WhereLoop *pLoops; /* List of all WhereLoop objects */ 463 Bitmask revMask; /* Mask of ORDER BY terms that need reversing */ 464 LogEst nRowOut; /* Estimated number of output rows */ 465 WhereClause sWC; /* Decomposition of the WHERE clause */ 466 WhereMaskSet sMaskSet; /* Map cursor numbers to bitmasks */ 467 WhereLevel a[1]; /* Information about each nest loop in WHERE */ 468 }; 469 470 /* 471 ** Private interfaces - callable only by other where.c routines. 472 ** 473 ** where.c: 474 */ 475 Bitmask sqlite3WhereGetMask(WhereMaskSet*,int); 476 #ifdef WHERETRACE_ENABLED 477 void sqlite3WhereClausePrint(WhereClause *pWC); 478 #endif 479 WhereTerm *sqlite3WhereFindTerm( 480 WhereClause *pWC, /* The WHERE clause to be searched */ 481 int iCur, /* Cursor number of LHS */ 482 int iColumn, /* Column number of LHS */ 483 Bitmask notReady, /* RHS must not overlap with this mask */ 484 u32 op, /* Mask of WO_xx values describing operator */ 485 Index *pIdx /* Must be compatible with this index, if not NULL */ 486 ); 487 488 /* wherecode.c: */ 489 #ifndef SQLITE_OMIT_EXPLAIN 490 int sqlite3WhereExplainOneScan( 491 Parse *pParse, /* Parse context */ 492 SrcList *pTabList, /* Table list this loop refers to */ 493 WhereLevel *pLevel, /* Scan to write OP_Explain opcode for */ 494 u16 wctrlFlags /* Flags passed to sqlite3WhereBegin() */ 495 ); 496 #else 497 # define sqlite3WhereExplainOneScan(u,v,w,x) 0 498 #endif /* SQLITE_OMIT_EXPLAIN */ 499 #ifdef SQLITE_ENABLE_STMT_SCANSTATUS 500 void sqlite3WhereAddScanStatus( 501 Vdbe *v, /* Vdbe to add scanstatus entry to */ 502 SrcList *pSrclist, /* FROM clause pLvl reads data from */ 503 WhereLevel *pLvl, /* Level to add scanstatus() entry for */ 504 int addrExplain /* Address of OP_Explain (or 0) */ 505 ); 506 #else 507 # define sqlite3WhereAddScanStatus(a, b, c, d) ((void)d) 508 #endif 509 Bitmask sqlite3WhereCodeOneLoopStart( 510 Parse *pParse, /* Parsing context */ 511 Vdbe *v, /* Prepared statement under construction */ 512 WhereInfo *pWInfo, /* Complete information about the WHERE clause */ 513 int iLevel, /* Which level of pWInfo->a[] should be coded */ 514 WhereLevel *pLevel, /* The current level pointer */ 515 Bitmask notReady /* Which tables are currently available */ 516 ); 517 518 /* whereexpr.c: */ 519 void sqlite3WhereClauseInit(WhereClause*,WhereInfo*); 520 void sqlite3WhereClauseClear(WhereClause*); 521 void sqlite3WhereSplit(WhereClause*,Expr*,u8); 522 Bitmask sqlite3WhereExprUsage(WhereMaskSet*, Expr*); 523 Bitmask sqlite3WhereExprUsageNN(WhereMaskSet*, Expr*); 524 Bitmask sqlite3WhereExprListUsage(WhereMaskSet*, ExprList*); 525 void sqlite3WhereExprAnalyze(SrcList*, WhereClause*); 526 void sqlite3WhereTabFuncArgs(Parse*, struct SrcList_item*, WhereClause*); 527 528 529 530 531 532 /* 533 ** Bitmasks for the operators on WhereTerm objects. These are all 534 ** operators that are of interest to the query planner. An 535 ** OR-ed combination of these values can be used when searching for 536 ** particular WhereTerms within a WhereClause. 537 ** 538 ** Value constraints: 539 ** WO_EQ == SQLITE_INDEX_CONSTRAINT_EQ 540 ** WO_LT == SQLITE_INDEX_CONSTRAINT_LT 541 ** WO_LE == SQLITE_INDEX_CONSTRAINT_LE 542 ** WO_GT == SQLITE_INDEX_CONSTRAINT_GT 543 ** WO_GE == SQLITE_INDEX_CONSTRAINT_GE 544 */ 545 #define WO_IN 0x0001 546 #define WO_EQ 0x0002 547 #define WO_LT (WO_EQ<<(TK_LT-TK_EQ)) 548 #define WO_LE (WO_EQ<<(TK_LE-TK_EQ)) 549 #define WO_GT (WO_EQ<<(TK_GT-TK_EQ)) 550 #define WO_GE (WO_EQ<<(TK_GE-TK_EQ)) 551 #define WO_AUX 0x0040 /* Op useful to virtual tables only */ 552 #define WO_IS 0x0080 553 #define WO_ISNULL 0x0100 554 #define WO_OR 0x0200 /* Two or more OR-connected terms */ 555 #define WO_AND 0x0400 /* Two or more AND-connected terms */ 556 #define WO_EQUIV 0x0800 /* Of the form A==B, both columns */ 557 #define WO_NOOP 0x1000 /* This term does not restrict search space */ 558 559 #define WO_ALL 0x1fff /* Mask of all possible WO_* values */ 560 #define WO_SINGLE 0x01ff /* Mask of all non-compound WO_* values */ 561 562 /* 563 ** These are definitions of bits in the WhereLoop.wsFlags field. 564 ** The particular combination of bits in each WhereLoop help to 565 ** determine the algorithm that WhereLoop represents. 566 */ 567 #define WHERE_COLUMN_EQ 0x00000001 /* x=EXPR */ 568 #define WHERE_COLUMN_RANGE 0x00000002 /* x<EXPR and/or x>EXPR */ 569 #define WHERE_COLUMN_IN 0x00000004 /* x IN (...) */ 570 #define WHERE_COLUMN_NULL 0x00000008 /* x IS NULL */ 571 #define WHERE_CONSTRAINT 0x0000000f /* Any of the WHERE_COLUMN_xxx values */ 572 #define WHERE_TOP_LIMIT 0x00000010 /* x<EXPR or x<=EXPR constraint */ 573 #define WHERE_BTM_LIMIT 0x00000020 /* x>EXPR or x>=EXPR constraint */ 574 #define WHERE_BOTH_LIMIT 0x00000030 /* Both x>EXPR and x<EXPR */ 575 #define WHERE_IDX_ONLY 0x00000040 /* Use index only - omit table */ 576 #define WHERE_IPK 0x00000100 /* x is the INTEGER PRIMARY KEY */ 577 #define WHERE_INDEXED 0x00000200 /* WhereLoop.u.btree.pIndex is valid */ 578 #define WHERE_VIRTUALTABLE 0x00000400 /* WhereLoop.u.vtab is valid */ 579 #define WHERE_IN_ABLE 0x00000800 /* Able to support an IN operator */ 580 #define WHERE_ONEROW 0x00001000 /* Selects no more than one row */ 581 #define WHERE_MULTI_OR 0x00002000 /* OR using multiple indices */ 582 #define WHERE_AUTO_INDEX 0x00004000 /* Uses an ephemeral index */ 583 #define WHERE_SKIPSCAN 0x00008000 /* Uses the skip-scan algorithm */ 584 #define WHERE_UNQ_WANTED 0x00010000 /* WHERE_ONEROW would have been helpful*/ 585 #define WHERE_PARTIALIDX 0x00020000 /* The automatic index is partial */ 586 #define WHERE_IN_EARLYOUT 0x00040000 /* Perhaps quit IN loops early */ 587