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 #ifndef SQLITE_WHEREINT_H 18 #define SQLITE_WHEREINT_H 19 20 21 /* Forward references 22 */ 23 typedef struct WhereClause WhereClause; 24 typedef struct WhereMaskSet WhereMaskSet; 25 typedef struct WhereOrInfo WhereOrInfo; 26 typedef struct WhereAndInfo WhereAndInfo; 27 typedef struct WhereLevel WhereLevel; 28 typedef struct WhereLoop WhereLoop; 29 typedef struct WherePath WherePath; 30 typedef struct WhereTerm WhereTerm; 31 typedef struct WhereLoopBuilder WhereLoopBuilder; 32 typedef struct WhereScan WhereScan; 33 typedef struct WhereOrCost WhereOrCost; 34 typedef struct WhereOrSet WhereOrSet; 35 36 /* 37 ** This object contains information needed to implement a single nested 38 ** loop in WHERE clause. 39 ** 40 ** Contrast this object with WhereLoop. This object describes the 41 ** implementation of the loop. WhereLoop describes the algorithm. 42 ** This object contains a pointer to the WhereLoop algorithm as one of 43 ** its elements. 44 ** 45 ** The WhereInfo object contains a single instance of this object for 46 ** each term in the FROM clause (which is to say, for each of the 47 ** nested loops as implemented). The order of WhereLevel objects determines 48 ** the loop nested order, with WhereInfo.a[0] being the outer loop and 49 ** WhereInfo.a[WhereInfo.nLevel-1] being the inner loop. 50 */ 51 struct WhereLevel { 52 int iLeftJoin; /* Memory cell used to implement LEFT OUTER JOIN */ 53 int iTabCur; /* The VDBE cursor used to access the table */ 54 int iIdxCur; /* The VDBE cursor used to access pIdx */ 55 int addrBrk; /* Jump here to break out of the loop */ 56 int addrNxt; /* Jump here to start the next IN combination */ 57 int addrSkip; /* Jump here for next iteration of skip-scan */ 58 int addrCont; /* Jump here to continue with the next loop cycle */ 59 int addrFirst; /* First instruction of interior of the loop */ 60 int addrBody; /* Beginning of the body of this loop */ 61 int regBignull; /* big-null flag reg. True if a NULL-scan is needed */ 62 int addrBignull; /* Jump here for next part of big-null scan */ 63 #ifndef SQLITE_LIKE_DOESNT_MATCH_BLOBS 64 u32 iLikeRepCntr; /* LIKE range processing counter register (times 2) */ 65 int addrLikeRep; /* LIKE range processing address */ 66 #endif 67 u8 iFrom; /* Which entry in the FROM clause */ 68 u8 op, p3, p5; /* Opcode, P3 & P5 of the opcode that ends the loop */ 69 int p1, p2; /* Operands of the opcode used to end the loop */ 70 union { /* Information that depends on pWLoop->wsFlags */ 71 struct { 72 int nIn; /* Number of entries in aInLoop[] */ 73 struct InLoop { 74 int iCur; /* The VDBE cursor used by this IN operator */ 75 int addrInTop; /* Top of the IN loop */ 76 int iBase; /* Base register of multi-key index record */ 77 int nPrefix; /* Number of prior entires in the key */ 78 u8 eEndLoopOp; /* IN Loop terminator. OP_Next or OP_Prev */ 79 } *aInLoop; /* Information about each nested IN operator */ 80 } in; /* Used when pWLoop->wsFlags&WHERE_IN_ABLE */ 81 Index *pCoveringIdx; /* Possible covering index for WHERE_MULTI_OR */ 82 } u; 83 struct WhereLoop *pWLoop; /* The selected WhereLoop object */ 84 Bitmask notReady; /* FROM entries not usable at this level */ 85 #ifdef SQLITE_ENABLE_STMT_SCANSTATUS 86 int addrVisit; /* Address at which row is visited */ 87 #endif 88 }; 89 90 /* 91 ** Each instance of this object represents an algorithm for evaluating one 92 ** term of a join. Every term of the FROM clause will have at least 93 ** one corresponding WhereLoop object (unless INDEXED BY constraints 94 ** prevent a query solution - which is an error) and many terms of the 95 ** FROM clause will have multiple WhereLoop objects, each describing a 96 ** potential way of implementing that FROM-clause term, together with 97 ** dependencies and cost estimates for using the chosen algorithm. 98 ** 99 ** Query planning consists of building up a collection of these WhereLoop 100 ** objects, then computing a particular sequence of WhereLoop objects, with 101 ** one WhereLoop object per FROM clause term, that satisfy all dependencies 102 ** and that minimize the overall cost. 103 */ 104 struct WhereLoop { 105 Bitmask prereq; /* Bitmask of other loops that must run first */ 106 Bitmask maskSelf; /* Bitmask identifying table iTab */ 107 #ifdef SQLITE_DEBUG 108 char cId; /* Symbolic ID of this loop for debugging use */ 109 #endif 110 u8 iTab; /* Position in FROM clause of table for this loop */ 111 u8 iSortIdx; /* Sorting index number. 0==None */ 112 LogEst rSetup; /* One-time setup cost (ex: create transient index) */ 113 LogEst rRun; /* Cost of running each loop */ 114 LogEst nOut; /* Estimated number of output rows */ 115 union { 116 struct { /* Information for internal btree tables */ 117 u16 nEq; /* Number of equality constraints */ 118 u16 nBtm; /* Size of BTM vector */ 119 u16 nTop; /* Size of TOP vector */ 120 u16 nDistinctCol; /* Index columns used to sort for DISTINCT */ 121 Index *pIndex; /* Index used, or NULL */ 122 } btree; 123 struct { /* Information for virtual tables */ 124 int idxNum; /* Index number */ 125 u8 needFree; /* True if sqlite3_free(idxStr) is needed */ 126 i8 isOrdered; /* True if satisfies ORDER BY */ 127 u16 omitMask; /* Terms that may be omitted */ 128 char *idxStr; /* Index identifier string */ 129 } vtab; 130 } u; 131 u32 wsFlags; /* WHERE_* flags describing the plan */ 132 u16 nLTerm; /* Number of entries in aLTerm[] */ 133 u16 nSkip; /* Number of NULL aLTerm[] entries */ 134 /**** whereLoopXfer() copies fields above ***********************/ 135 # define WHERE_LOOP_XFER_SZ offsetof(WhereLoop,nLSlot) 136 u16 nLSlot; /* Number of slots allocated for aLTerm[] */ 137 WhereTerm **aLTerm; /* WhereTerms used */ 138 WhereLoop *pNextLoop; /* Next WhereLoop object in the WhereClause */ 139 WhereTerm *aLTermSpace[3]; /* Initial aLTerm[] space */ 140 }; 141 142 /* This object holds the prerequisites and the cost of running a 143 ** subquery on one operand of an OR operator in the WHERE clause. 144 ** See WhereOrSet for additional information 145 */ 146 struct WhereOrCost { 147 Bitmask prereq; /* Prerequisites */ 148 LogEst rRun; /* Cost of running this subquery */ 149 LogEst nOut; /* Number of outputs for this subquery */ 150 }; 151 152 /* The WhereOrSet object holds a set of possible WhereOrCosts that 153 ** correspond to the subquery(s) of OR-clause processing. Only the 154 ** best N_OR_COST elements are retained. 155 */ 156 #define N_OR_COST 3 157 struct WhereOrSet { 158 u16 n; /* Number of valid a[] entries */ 159 WhereOrCost a[N_OR_COST]; /* Set of best costs */ 160 }; 161 162 /* 163 ** Each instance of this object holds a sequence of WhereLoop objects 164 ** that implement some or all of a query plan. 165 ** 166 ** Think of each WhereLoop object as a node in a graph with arcs 167 ** showing dependencies and costs for travelling between nodes. (That is 168 ** not a completely accurate description because WhereLoop costs are a 169 ** vector, not a scalar, and because dependencies are many-to-one, not 170 ** one-to-one as are graph nodes. But it is a useful visualization aid.) 171 ** Then a WherePath object is a path through the graph that visits some 172 ** or all of the WhereLoop objects once. 173 ** 174 ** The "solver" works by creating the N best WherePath objects of length 175 ** 1. Then using those as a basis to compute the N best WherePath objects 176 ** of length 2. And so forth until the length of WherePaths equals the 177 ** number of nodes in the FROM clause. The best (lowest cost) WherePath 178 ** at the end is the chosen query plan. 179 */ 180 struct WherePath { 181 Bitmask maskLoop; /* Bitmask of all WhereLoop objects in this path */ 182 Bitmask revLoop; /* aLoop[]s that should be reversed for ORDER BY */ 183 LogEst nRow; /* Estimated number of rows generated by this path */ 184 LogEst rCost; /* Total cost of this path */ 185 LogEst rUnsorted; /* Total cost of this path ignoring sorting costs */ 186 i8 isOrdered; /* No. of ORDER BY terms satisfied. -1 for unknown */ 187 WhereLoop **aLoop; /* Array of WhereLoop objects implementing this path */ 188 }; 189 190 /* 191 ** The query generator uses an array of instances of this structure to 192 ** help it analyze the subexpressions of the WHERE clause. Each WHERE 193 ** clause subexpression is separated from the others by AND operators, 194 ** usually, or sometimes subexpressions separated by OR. 195 ** 196 ** All WhereTerms are collected into a single WhereClause structure. 197 ** The following identity holds: 198 ** 199 ** WhereTerm.pWC->a[WhereTerm.idx] == WhereTerm 200 ** 201 ** When a term is of the form: 202 ** 203 ** X <op> <expr> 204 ** 205 ** where X is a column name and <op> is one of certain operators, 206 ** then WhereTerm.leftCursor and WhereTerm.u.leftColumn record the 207 ** cursor number and column number for X. WhereTerm.eOperator records 208 ** the <op> using a bitmask encoding defined by WO_xxx below. The 209 ** use of a bitmask encoding for the operator allows us to search 210 ** quickly for terms that match any of several different operators. 211 ** 212 ** A WhereTerm might also be two or more subterms connected by OR: 213 ** 214 ** (t1.X <op> <expr>) OR (t1.Y <op> <expr>) OR .... 215 ** 216 ** In this second case, wtFlag has the TERM_ORINFO bit set and eOperator==WO_OR 217 ** and the WhereTerm.u.pOrInfo field points to auxiliary information that 218 ** is collected about the OR clause. 219 ** 220 ** If a term in the WHERE clause does not match either of the two previous 221 ** categories, then eOperator==0. The WhereTerm.pExpr field is still set 222 ** to the original subexpression content and wtFlags is set up appropriately 223 ** but no other fields in the WhereTerm object are meaningful. 224 ** 225 ** When eOperator!=0, prereqRight and prereqAll record sets of cursor numbers, 226 ** but they do so indirectly. A single WhereMaskSet structure translates 227 ** cursor number into bits and the translated bit is stored in the prereq 228 ** fields. The translation is used in order to maximize the number of 229 ** bits that will fit in a Bitmask. The VDBE cursor numbers might be 230 ** spread out over the non-negative integers. For example, the cursor 231 ** numbers might be 3, 8, 9, 10, 20, 23, 41, and 45. The WhereMaskSet 232 ** translates these sparse cursor numbers into consecutive integers 233 ** beginning with 0 in order to make the best possible use of the available 234 ** bits in the Bitmask. So, in the example above, the cursor numbers 235 ** would be mapped into integers 0 through 7. 236 ** 237 ** The number of terms in a join is limited by the number of bits 238 ** in prereqRight and prereqAll. The default is 64 bits, hence SQLite 239 ** is only able to process joins with 64 or fewer tables. 240 */ 241 struct WhereTerm { 242 Expr *pExpr; /* Pointer to the subexpression that is this term */ 243 WhereClause *pWC; /* The clause this term is part of */ 244 LogEst truthProb; /* Probability of truth for this expression */ 245 u16 wtFlags; /* TERM_xxx bit flags. See below */ 246 u16 eOperator; /* A WO_xx value describing <op> */ 247 u8 nChild; /* Number of children that must disable us */ 248 u8 eMatchOp; /* Op for vtab MATCH/LIKE/GLOB/REGEXP terms */ 249 int iParent; /* Disable pWC->a[iParent] when this term disabled */ 250 int leftCursor; /* Cursor number of X in "X <op> <expr>" */ 251 union { 252 struct { 253 int leftColumn; /* Column number of X in "X <op> <expr>" */ 254 int iField; /* Field in (?,?,?) IN (SELECT...) vector */ 255 } x; /* Opcode other than OP_OR or OP_AND */ 256 WhereOrInfo *pOrInfo; /* Extra information if (eOperator & WO_OR)!=0 */ 257 WhereAndInfo *pAndInfo; /* Extra information if (eOperator& WO_AND)!=0 */ 258 } u; 259 Bitmask prereqRight; /* Bitmask of tables used by pExpr->pRight */ 260 Bitmask prereqAll; /* Bitmask of tables referenced by pExpr */ 261 }; 262 263 /* 264 ** Allowed values of WhereTerm.wtFlags 265 */ 266 #define TERM_DYNAMIC 0x0001 /* Need to call sqlite3ExprDelete(db, pExpr) */ 267 #define TERM_VIRTUAL 0x0002 /* Added by the optimizer. Do not code */ 268 #define TERM_CODED 0x0004 /* This term is already coded */ 269 #define TERM_COPIED 0x0008 /* Has a child */ 270 #define TERM_ORINFO 0x0010 /* Need to free the WhereTerm.u.pOrInfo object */ 271 #define TERM_ANDINFO 0x0020 /* Need to free the WhereTerm.u.pAndInfo obj */ 272 #define TERM_OR_OK 0x0040 /* Used during OR-clause processing */ 273 #define TERM_VNULL 0x0080 /* Manufactured x>NULL or x<=NULL term */ 274 #define TERM_LIKEOPT 0x0100 /* Virtual terms from the LIKE optimization */ 275 #define TERM_LIKECOND 0x0200 /* Conditionally this LIKE operator term */ 276 #define TERM_LIKE 0x0400 /* The original LIKE operator */ 277 #define TERM_IS 0x0800 /* Term.pExpr is an IS operator */ 278 #define TERM_VARSELECT 0x1000 /* Term.pExpr contains a correlated sub-query */ 279 #define TERM_HEURTRUTH 0x2000 /* Heuristic truthProb used */ 280 #ifdef SQLITE_ENABLE_STAT4 281 # define TERM_HIGHTRUTH 0x4000 /* Term excludes few rows */ 282 #else 283 # define TERM_HIGHTRUTH 0 /* Only used with STAT4 */ 284 #endif 285 286 /* 287 ** An instance of the WhereScan object is used as an iterator for locating 288 ** terms in the WHERE clause that are useful to the query planner. 289 */ 290 struct WhereScan { 291 WhereClause *pOrigWC; /* Original, innermost WhereClause */ 292 WhereClause *pWC; /* WhereClause currently being scanned */ 293 const char *zCollName; /* Required collating sequence, if not NULL */ 294 Expr *pIdxExpr; /* Search for this index expression */ 295 int k; /* Resume scanning at this->pWC->a[this->k] */ 296 u32 opMask; /* Acceptable operators */ 297 char idxaff; /* Must match this affinity, if zCollName!=NULL */ 298 unsigned char iEquiv; /* Current slot in aiCur[] and aiColumn[] */ 299 unsigned char nEquiv; /* Number of entries in aiCur[] and aiColumn[] */ 300 int aiCur[11]; /* Cursors in the equivalence class */ 301 i16 aiColumn[11]; /* Corresponding column number in the eq-class */ 302 }; 303 304 /* 305 ** An instance of the following structure holds all information about a 306 ** WHERE clause. Mostly this is a container for one or more WhereTerms. 307 ** 308 ** Explanation of pOuter: For a WHERE clause of the form 309 ** 310 ** a AND ((b AND c) OR (d AND e)) AND f 311 ** 312 ** There are separate WhereClause objects for the whole clause and for 313 ** the subclauses "(b AND c)" and "(d AND e)". The pOuter field of the 314 ** subclauses points to the WhereClause object for the whole clause. 315 */ 316 struct WhereClause { 317 WhereInfo *pWInfo; /* WHERE clause processing context */ 318 WhereClause *pOuter; /* Outer conjunction */ 319 u8 op; /* Split operator. TK_AND or TK_OR */ 320 u8 hasOr; /* True if any a[].eOperator is WO_OR */ 321 int nTerm; /* Number of terms */ 322 int nSlot; /* Number of entries in a[] */ 323 int nBase; /* Number of terms through the last non-Virtual */ 324 WhereTerm *a; /* Each a[] describes a term of the WHERE cluase */ 325 #if defined(SQLITE_SMALL_STACK) 326 WhereTerm aStatic[1]; /* Initial static space for a[] */ 327 #else 328 WhereTerm aStatic[8]; /* Initial static space for a[] */ 329 #endif 330 }; 331 332 /* 333 ** A WhereTerm with eOperator==WO_OR has its u.pOrInfo pointer set to 334 ** a dynamically allocated instance of the following structure. 335 */ 336 struct WhereOrInfo { 337 WhereClause wc; /* Decomposition into subterms */ 338 Bitmask indexable; /* Bitmask of all indexable tables in the clause */ 339 }; 340 341 /* 342 ** A WhereTerm with eOperator==WO_AND has its u.pAndInfo pointer set to 343 ** a dynamically allocated instance of the following structure. 344 */ 345 struct WhereAndInfo { 346 WhereClause wc; /* The subexpression broken out */ 347 }; 348 349 /* 350 ** An instance of the following structure keeps track of a mapping 351 ** between VDBE cursor numbers and bits of the bitmasks in WhereTerm. 352 ** 353 ** The VDBE cursor numbers are small integers contained in 354 ** SrcList_item.iCursor and Expr.iTable fields. For any given WHERE 355 ** clause, the cursor numbers might not begin with 0 and they might 356 ** contain gaps in the numbering sequence. But we want to make maximum 357 ** use of the bits in our bitmasks. This structure provides a mapping 358 ** from the sparse cursor numbers into consecutive integers beginning 359 ** with 0. 360 ** 361 ** If WhereMaskSet.ix[A]==B it means that The A-th bit of a Bitmask 362 ** corresponds VDBE cursor number B. The A-th bit of a bitmask is 1<<A. 363 ** 364 ** For example, if the WHERE clause expression used these VDBE 365 ** cursors: 4, 5, 8, 29, 57, 73. Then the WhereMaskSet structure 366 ** would map those cursor numbers into bits 0 through 5. 367 ** 368 ** Note that the mapping is not necessarily ordered. In the example 369 ** above, the mapping might go like this: 4->3, 5->1, 8->2, 29->0, 370 ** 57->5, 73->4. Or one of 719 other combinations might be used. It 371 ** does not really matter. What is important is that sparse cursor 372 ** numbers all get mapped into bit numbers that begin with 0 and contain 373 ** no gaps. 374 */ 375 struct WhereMaskSet { 376 int bVarSelect; /* Used by sqlite3WhereExprUsage() */ 377 int n; /* Number of assigned cursor values */ 378 int ix[BMS]; /* Cursor assigned to each bit */ 379 }; 380 381 /* 382 ** This object is a convenience wrapper holding all information needed 383 ** to construct WhereLoop objects for a particular query. 384 */ 385 struct WhereLoopBuilder { 386 WhereInfo *pWInfo; /* Information about this WHERE */ 387 WhereClause *pWC; /* WHERE clause terms */ 388 ExprList *pOrderBy; /* ORDER BY clause */ 389 WhereLoop *pNew; /* Template WhereLoop */ 390 WhereOrSet *pOrSet; /* Record best loops here, if not NULL */ 391 #ifdef SQLITE_ENABLE_STAT4 392 UnpackedRecord *pRec; /* Probe for stat4 (if required) */ 393 int nRecValid; /* Number of valid fields currently in pRec */ 394 #endif 395 unsigned char bldFlags1; /* First set of SQLITE_BLDF_* flags */ 396 unsigned char bldFlags2; /* Second set of SQLITE_BLDF_* flags */ 397 unsigned int iPlanLimit; /* Search limiter */ 398 }; 399 400 /* Allowed values for WhereLoopBuider.bldFlags */ 401 #define SQLITE_BLDF1_INDEXED 0x0001 /* An index is used */ 402 #define SQLITE_BLDF1_UNIQUE 0x0002 /* All keys of a UNIQUE index used */ 403 404 #define SQLITE_BLDF2_2NDPASS 0x0004 /* Second builder pass needed */ 405 406 /* The WhereLoopBuilder.iPlanLimit is used to limit the number of 407 ** index+constraint combinations the query planner will consider for a 408 ** particular query. If this parameter is unlimited, then certain 409 ** pathological queries can spend excess time in the sqlite3WhereBegin() 410 ** routine. The limit is high enough that is should not impact real-world 411 ** queries. 412 ** 413 ** SQLITE_QUERY_PLANNER_LIMIT is the baseline limit. The limit is 414 ** increased by SQLITE_QUERY_PLANNER_LIMIT_INCR before each term of the FROM 415 ** clause is processed, so that every table in a join is guaranteed to be 416 ** able to propose a some index+constraint combinations even if the initial 417 ** baseline limit was exhausted by prior tables of the join. 418 */ 419 #ifndef SQLITE_QUERY_PLANNER_LIMIT 420 # define SQLITE_QUERY_PLANNER_LIMIT 20000 421 #endif 422 #ifndef SQLITE_QUERY_PLANNER_LIMIT_INCR 423 # define SQLITE_QUERY_PLANNER_LIMIT_INCR 1000 424 #endif 425 426 /* 427 ** Each instance of this object records a change to a single node 428 ** in an expression tree to cause that node to point to a column 429 ** of an index rather than an expression or a virtual column. All 430 ** such transformations need to be undone at the end of WHERE clause 431 ** processing. 432 */ 433 typedef struct WhereExprMod WhereExprMod; 434 struct WhereExprMod { 435 WhereExprMod *pNext; /* Next translation on a list of them all */ 436 Expr *pExpr; /* The Expr node that was transformed */ 437 Expr orig; /* Original value of the Expr node */ 438 }; 439 440 /* 441 ** The WHERE clause processing routine has two halves. The 442 ** first part does the start of the WHERE loop and the second 443 ** half does the tail of the WHERE loop. An instance of 444 ** this structure is returned by the first half and passed 445 ** into the second half to give some continuity. 446 ** 447 ** An instance of this object holds the complete state of the query 448 ** planner. 449 */ 450 struct WhereInfo { 451 Parse *pParse; /* Parsing and code generating context */ 452 SrcList *pTabList; /* List of tables in the join */ 453 ExprList *pOrderBy; /* The ORDER BY clause or NULL */ 454 ExprList *pResultSet; /* Result set of the query */ 455 Expr *pWhere; /* The complete WHERE clause */ 456 int aiCurOnePass[2]; /* OP_OpenWrite cursors for the ONEPASS opt */ 457 int iContinue; /* Jump here to continue with next record */ 458 int iBreak; /* Jump here to break out of the loop */ 459 int savedNQueryLoop; /* pParse->nQueryLoop outside the WHERE loop */ 460 u16 wctrlFlags; /* Flags originally passed to sqlite3WhereBegin() */ 461 LogEst iLimit; /* LIMIT if wctrlFlags has WHERE_USE_LIMIT */ 462 u8 nLevel; /* Number of nested loop */ 463 i8 nOBSat; /* Number of ORDER BY terms satisfied by indices */ 464 u8 eOnePass; /* ONEPASS_OFF, or _SINGLE, or _MULTI */ 465 u8 eDistinct; /* One of the WHERE_DISTINCT_* values */ 466 unsigned bDeferredSeek :1; /* Uses OP_DeferredSeek */ 467 unsigned untestedTerms :1; /* Not all WHERE terms resolved by outer loop */ 468 unsigned bOrderedInnerLoop:1;/* True if only the inner-most loop is ordered */ 469 unsigned sorted :1; /* True if really sorted (not just grouped) */ 470 LogEst nRowOut; /* Estimated number of output rows */ 471 int iTop; /* The very beginning of the WHERE loop */ 472 int iEndWhere; /* End of the WHERE clause itself */ 473 WhereLoop *pLoops; /* List of all WhereLoop objects */ 474 WhereExprMod *pExprMods; /* Expression modifications */ 475 Bitmask revMask; /* Mask of ORDER BY terms that need reversing */ 476 WhereClause sWC; /* Decomposition of the WHERE clause */ 477 WhereMaskSet sMaskSet; /* Map cursor numbers to bitmasks */ 478 WhereLevel a[1]; /* Information about each nest loop in WHERE */ 479 }; 480 481 /* 482 ** Private interfaces - callable only by other where.c routines. 483 ** 484 ** where.c: 485 */ 486 Bitmask sqlite3WhereGetMask(WhereMaskSet*,int); 487 #ifdef WHERETRACE_ENABLED 488 void sqlite3WhereClausePrint(WhereClause *pWC); 489 void sqlite3WhereTermPrint(WhereTerm *pTerm, int iTerm); 490 void sqlite3WhereLoopPrint(WhereLoop *p, WhereClause *pWC); 491 #endif 492 WhereTerm *sqlite3WhereFindTerm( 493 WhereClause *pWC, /* The WHERE clause to be searched */ 494 int iCur, /* Cursor number of LHS */ 495 int iColumn, /* Column number of LHS */ 496 Bitmask notReady, /* RHS must not overlap with this mask */ 497 u32 op, /* Mask of WO_xx values describing operator */ 498 Index *pIdx /* Must be compatible with this index, if not NULL */ 499 ); 500 501 /* wherecode.c: */ 502 #ifndef SQLITE_OMIT_EXPLAIN 503 int sqlite3WhereExplainOneScan( 504 Parse *pParse, /* Parse context */ 505 SrcList *pTabList, /* Table list this loop refers to */ 506 WhereLevel *pLevel, /* Scan to write OP_Explain opcode for */ 507 u16 wctrlFlags /* Flags passed to sqlite3WhereBegin() */ 508 ); 509 #else 510 # define sqlite3WhereExplainOneScan(u,v,w,x) 0 511 #endif /* SQLITE_OMIT_EXPLAIN */ 512 #ifdef SQLITE_ENABLE_STMT_SCANSTATUS 513 void sqlite3WhereAddScanStatus( 514 Vdbe *v, /* Vdbe to add scanstatus entry to */ 515 SrcList *pSrclist, /* FROM clause pLvl reads data from */ 516 WhereLevel *pLvl, /* Level to add scanstatus() entry for */ 517 int addrExplain /* Address of OP_Explain (or 0) */ 518 ); 519 #else 520 # define sqlite3WhereAddScanStatus(a, b, c, d) ((void)d) 521 #endif 522 Bitmask sqlite3WhereCodeOneLoopStart( 523 Parse *pParse, /* Parsing context */ 524 Vdbe *v, /* Prepared statement under construction */ 525 WhereInfo *pWInfo, /* Complete information about the WHERE clause */ 526 int iLevel, /* Which level of pWInfo->a[] should be coded */ 527 WhereLevel *pLevel, /* The current level pointer */ 528 Bitmask notReady /* Which tables are currently available */ 529 ); 530 531 /* whereexpr.c: */ 532 void sqlite3WhereClauseInit(WhereClause*,WhereInfo*); 533 void sqlite3WhereClauseClear(WhereClause*); 534 void sqlite3WhereSplit(WhereClause*,Expr*,u8); 535 Bitmask sqlite3WhereExprUsage(WhereMaskSet*, Expr*); 536 Bitmask sqlite3WhereExprUsageNN(WhereMaskSet*, Expr*); 537 Bitmask sqlite3WhereExprListUsage(WhereMaskSet*, ExprList*); 538 void sqlite3WhereExprAnalyze(SrcList*, WhereClause*); 539 void sqlite3WhereTabFuncArgs(Parse*, SrcItem*, WhereClause*); 540 541 542 543 544 545 /* 546 ** Bitmasks for the operators on WhereTerm objects. These are all 547 ** operators that are of interest to the query planner. An 548 ** OR-ed combination of these values can be used when searching for 549 ** particular WhereTerms within a WhereClause. 550 ** 551 ** Value constraints: 552 ** WO_EQ == SQLITE_INDEX_CONSTRAINT_EQ 553 ** WO_LT == SQLITE_INDEX_CONSTRAINT_LT 554 ** WO_LE == SQLITE_INDEX_CONSTRAINT_LE 555 ** WO_GT == SQLITE_INDEX_CONSTRAINT_GT 556 ** WO_GE == SQLITE_INDEX_CONSTRAINT_GE 557 */ 558 #define WO_IN 0x0001 559 #define WO_EQ 0x0002 560 #define WO_LT (WO_EQ<<(TK_LT-TK_EQ)) 561 #define WO_LE (WO_EQ<<(TK_LE-TK_EQ)) 562 #define WO_GT (WO_EQ<<(TK_GT-TK_EQ)) 563 #define WO_GE (WO_EQ<<(TK_GE-TK_EQ)) 564 #define WO_AUX 0x0040 /* Op useful to virtual tables only */ 565 #define WO_IS 0x0080 566 #define WO_ISNULL 0x0100 567 #define WO_OR 0x0200 /* Two or more OR-connected terms */ 568 #define WO_AND 0x0400 /* Two or more AND-connected terms */ 569 #define WO_EQUIV 0x0800 /* Of the form A==B, both columns */ 570 #define WO_NOOP 0x1000 /* This term does not restrict search space */ 571 572 #define WO_ALL 0x1fff /* Mask of all possible WO_* values */ 573 #define WO_SINGLE 0x01ff /* Mask of all non-compound WO_* values */ 574 575 /* 576 ** These are definitions of bits in the WhereLoop.wsFlags field. 577 ** The particular combination of bits in each WhereLoop help to 578 ** determine the algorithm that WhereLoop represents. 579 */ 580 #define WHERE_COLUMN_EQ 0x00000001 /* x=EXPR */ 581 #define WHERE_COLUMN_RANGE 0x00000002 /* x<EXPR and/or x>EXPR */ 582 #define WHERE_COLUMN_IN 0x00000004 /* x IN (...) */ 583 #define WHERE_COLUMN_NULL 0x00000008 /* x IS NULL */ 584 #define WHERE_CONSTRAINT 0x0000000f /* Any of the WHERE_COLUMN_xxx values */ 585 #define WHERE_TOP_LIMIT 0x00000010 /* x<EXPR or x<=EXPR constraint */ 586 #define WHERE_BTM_LIMIT 0x00000020 /* x>EXPR or x>=EXPR constraint */ 587 #define WHERE_BOTH_LIMIT 0x00000030 /* Both x>EXPR and x<EXPR */ 588 #define WHERE_IDX_ONLY 0x00000040 /* Use index only - omit table */ 589 #define WHERE_IPK 0x00000100 /* x is the INTEGER PRIMARY KEY */ 590 #define WHERE_INDEXED 0x00000200 /* WhereLoop.u.btree.pIndex is valid */ 591 #define WHERE_VIRTUALTABLE 0x00000400 /* WhereLoop.u.vtab is valid */ 592 #define WHERE_IN_ABLE 0x00000800 /* Able to support an IN operator */ 593 #define WHERE_ONEROW 0x00001000 /* Selects no more than one row */ 594 #define WHERE_MULTI_OR 0x00002000 /* OR using multiple indices */ 595 #define WHERE_AUTO_INDEX 0x00004000 /* Uses an ephemeral index */ 596 #define WHERE_SKIPSCAN 0x00008000 /* Uses the skip-scan algorithm */ 597 #define WHERE_UNQ_WANTED 0x00010000 /* WHERE_ONEROW would have been helpful*/ 598 #define WHERE_PARTIALIDX 0x00020000 /* The automatic index is partial */ 599 #define WHERE_IN_EARLYOUT 0x00040000 /* Perhaps quit IN loops early */ 600 #define WHERE_BIGNULL_SORT 0x00080000 /* Column nEq of index is BIGNULL */ 601 #define WHERE_IN_SEEKSCAN 0x00100000 /* Seek-scan optimization for IN */ 602 #define WHERE_TRANSCONS 0x00200000 /* Uses a transitive constraint */ 603 604 #endif /* !defined(SQLITE_WHEREINT_H) */ 605