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 int regFilter; /* Bloom filter */ 68 u8 iFrom; /* Which entry in the FROM clause */ 69 u8 op, p3, p5; /* Opcode, P3 & P5 of the opcode that ends the loop */ 70 int p1, p2; /* Operands of the opcode used to end the loop */ 71 union { /* Information that depends on pWLoop->wsFlags */ 72 struct { 73 int nIn; /* Number of entries in aInLoop[] */ 74 struct InLoop { 75 int iCur; /* The VDBE cursor used by this IN operator */ 76 int addrInTop; /* Top of the IN loop */ 77 int iBase; /* Base register of multi-key index record */ 78 int nPrefix; /* Number of prior entires in the key */ 79 u8 eEndLoopOp; /* IN Loop terminator. OP_Next or OP_Prev */ 80 } *aInLoop; /* Information about each nested IN operator */ 81 } in; /* Used when pWLoop->wsFlags&WHERE_IN_ABLE */ 82 Index *pCoveringIdx; /* Possible covering index for WHERE_MULTI_OR */ 83 } u; 84 struct WhereLoop *pWLoop; /* The selected WhereLoop object */ 85 Bitmask notReady; /* FROM entries not usable at this level */ 86 #ifdef SQLITE_ENABLE_STMT_SCANSTATUS 87 int addrVisit; /* Address at which row is visited */ 88 #endif 89 }; 90 91 /* 92 ** Each instance of this object represents an algorithm for evaluating one 93 ** term of a join. Every term of the FROM clause will have at least 94 ** one corresponding WhereLoop object (unless INDEXED BY constraints 95 ** prevent a query solution - which is an error) and many terms of the 96 ** FROM clause will have multiple WhereLoop objects, each describing a 97 ** potential way of implementing that FROM-clause term, together with 98 ** dependencies and cost estimates for using the chosen algorithm. 99 ** 100 ** Query planning consists of building up a collection of these WhereLoop 101 ** objects, then computing a particular sequence of WhereLoop objects, with 102 ** one WhereLoop object per FROM clause term, that satisfy all dependencies 103 ** and that minimize the overall cost. 104 */ 105 struct WhereLoop { 106 Bitmask prereq; /* Bitmask of other loops that must run first */ 107 Bitmask maskSelf; /* Bitmask identifying table iTab */ 108 #ifdef SQLITE_DEBUG 109 char cId; /* Symbolic ID of this loop for debugging use */ 110 #endif 111 u8 iTab; /* Position in FROM clause of table for this loop */ 112 u8 iSortIdx; /* Sorting index number. 0==None */ 113 LogEst rSetup; /* One-time setup cost (ex: create transient index) */ 114 LogEst rRun; /* Cost of running each loop */ 115 LogEst nOut; /* Estimated number of output rows */ 116 union { 117 struct { /* Information for internal btree tables */ 118 u16 nEq; /* Number of equality constraints */ 119 u16 nBtm; /* Size of BTM vector */ 120 u16 nTop; /* Size of TOP vector */ 121 u16 nDistinctCol; /* Index columns used to sort for DISTINCT */ 122 Index *pIndex; /* Index used, or NULL */ 123 } btree; 124 struct { /* Information for virtual tables */ 125 int idxNum; /* Index number */ 126 u32 needFree : 1; /* True if sqlite3_free(idxStr) is needed */ 127 u32 bOmitOffset : 1; /* True to let virtual table handle offset */ 128 i8 isOrdered; /* True if satisfies ORDER BY */ 129 u16 omitMask; /* Terms that may be omitted */ 130 char *idxStr; /* Index identifier string */ 131 u32 mHandleIn; /* Terms to handle as IN(...) instead of == */ 132 } vtab; 133 } u; 134 u32 wsFlags; /* WHERE_* flags describing the plan */ 135 u16 nLTerm; /* Number of entries in aLTerm[] */ 136 u16 nSkip; /* Number of NULL aLTerm[] entries */ 137 /**** whereLoopXfer() copies fields above ***********************/ 138 # define WHERE_LOOP_XFER_SZ offsetof(WhereLoop,nLSlot) 139 u16 nLSlot; /* Number of slots allocated for aLTerm[] */ 140 WhereTerm **aLTerm; /* WhereTerms used */ 141 WhereLoop *pNextLoop; /* Next WhereLoop object in the WhereClause */ 142 WhereTerm *aLTermSpace[3]; /* Initial aLTerm[] space */ 143 }; 144 145 /* This object holds the prerequisites and the cost of running a 146 ** subquery on one operand of an OR operator in the WHERE clause. 147 ** See WhereOrSet for additional information 148 */ 149 struct WhereOrCost { 150 Bitmask prereq; /* Prerequisites */ 151 LogEst rRun; /* Cost of running this subquery */ 152 LogEst nOut; /* Number of outputs for this subquery */ 153 }; 154 155 /* The WhereOrSet object holds a set of possible WhereOrCosts that 156 ** correspond to the subquery(s) of OR-clause processing. Only the 157 ** best N_OR_COST elements are retained. 158 */ 159 #define N_OR_COST 3 160 struct WhereOrSet { 161 u16 n; /* Number of valid a[] entries */ 162 WhereOrCost a[N_OR_COST]; /* Set of best costs */ 163 }; 164 165 /* 166 ** Each instance of this object holds a sequence of WhereLoop objects 167 ** that implement some or all of a query plan. 168 ** 169 ** Think of each WhereLoop object as a node in a graph with arcs 170 ** showing dependencies and costs for travelling between nodes. (That is 171 ** not a completely accurate description because WhereLoop costs are a 172 ** vector, not a scalar, and because dependencies are many-to-one, not 173 ** one-to-one as are graph nodes. But it is a useful visualization aid.) 174 ** Then a WherePath object is a path through the graph that visits some 175 ** or all of the WhereLoop objects once. 176 ** 177 ** The "solver" works by creating the N best WherePath objects of length 178 ** 1. Then using those as a basis to compute the N best WherePath objects 179 ** of length 2. And so forth until the length of WherePaths equals the 180 ** number of nodes in the FROM clause. The best (lowest cost) WherePath 181 ** at the end is the chosen query plan. 182 */ 183 struct WherePath { 184 Bitmask maskLoop; /* Bitmask of all WhereLoop objects in this path */ 185 Bitmask revLoop; /* aLoop[]s that should be reversed for ORDER BY */ 186 LogEst nRow; /* Estimated number of rows generated by this path */ 187 LogEst rCost; /* Total cost of this path */ 188 LogEst rUnsorted; /* Total cost of this path ignoring sorting costs */ 189 i8 isOrdered; /* No. of ORDER BY terms satisfied. -1 for unknown */ 190 WhereLoop **aLoop; /* Array of WhereLoop objects implementing this path */ 191 }; 192 193 /* 194 ** The query generator uses an array of instances of this structure to 195 ** help it analyze the subexpressions of the WHERE clause. Each WHERE 196 ** clause subexpression is separated from the others by AND operators, 197 ** usually, or sometimes subexpressions separated by OR. 198 ** 199 ** All WhereTerms are collected into a single WhereClause structure. 200 ** The following identity holds: 201 ** 202 ** WhereTerm.pWC->a[WhereTerm.idx] == WhereTerm 203 ** 204 ** When a term is of the form: 205 ** 206 ** X <op> <expr> 207 ** 208 ** where X is a column name and <op> is one of certain operators, 209 ** then WhereTerm.leftCursor and WhereTerm.u.leftColumn record the 210 ** cursor number and column number for X. WhereTerm.eOperator records 211 ** the <op> using a bitmask encoding defined by WO_xxx below. The 212 ** use of a bitmask encoding for the operator allows us to search 213 ** quickly for terms that match any of several different operators. 214 ** 215 ** A WhereTerm might also be two or more subterms connected by OR: 216 ** 217 ** (t1.X <op> <expr>) OR (t1.Y <op> <expr>) OR .... 218 ** 219 ** In this second case, wtFlag has the TERM_ORINFO bit set and eOperator==WO_OR 220 ** and the WhereTerm.u.pOrInfo field points to auxiliary information that 221 ** is collected about the OR clause. 222 ** 223 ** If a term in the WHERE clause does not match either of the two previous 224 ** categories, then eOperator==0. The WhereTerm.pExpr field is still set 225 ** to the original subexpression content and wtFlags is set up appropriately 226 ** but no other fields in the WhereTerm object are meaningful. 227 ** 228 ** When eOperator!=0, prereqRight and prereqAll record sets of cursor numbers, 229 ** but they do so indirectly. A single WhereMaskSet structure translates 230 ** cursor number into bits and the translated bit is stored in the prereq 231 ** fields. The translation is used in order to maximize the number of 232 ** bits that will fit in a Bitmask. The VDBE cursor numbers might be 233 ** spread out over the non-negative integers. For example, the cursor 234 ** numbers might be 3, 8, 9, 10, 20, 23, 41, and 45. The WhereMaskSet 235 ** translates these sparse cursor numbers into consecutive integers 236 ** beginning with 0 in order to make the best possible use of the available 237 ** bits in the Bitmask. So, in the example above, the cursor numbers 238 ** would be mapped into integers 0 through 7. 239 ** 240 ** The number of terms in a join is limited by the number of bits 241 ** in prereqRight and prereqAll. The default is 64 bits, hence SQLite 242 ** is only able to process joins with 64 or fewer tables. 243 */ 244 struct WhereTerm { 245 Expr *pExpr; /* Pointer to the subexpression that is this term */ 246 WhereClause *pWC; /* The clause this term is part of */ 247 LogEst truthProb; /* Probability of truth for this expression */ 248 u16 wtFlags; /* TERM_xxx bit flags. See below */ 249 u16 eOperator; /* A WO_xx value describing <op> */ 250 u8 nChild; /* Number of children that must disable us */ 251 u8 eMatchOp; /* Op for vtab MATCH/LIKE/GLOB/REGEXP terms */ 252 int iParent; /* Disable pWC->a[iParent] when this term disabled */ 253 int leftCursor; /* Cursor number of X in "X <op> <expr>" */ 254 union { 255 struct { 256 int leftColumn; /* Column number of X in "X <op> <expr>" */ 257 int iField; /* Field in (?,?,?) IN (SELECT...) vector */ 258 } x; /* Opcode other than OP_OR or OP_AND */ 259 WhereOrInfo *pOrInfo; /* Extra information if (eOperator & WO_OR)!=0 */ 260 WhereAndInfo *pAndInfo; /* Extra information if (eOperator& WO_AND)!=0 */ 261 } u; 262 Bitmask prereqRight; /* Bitmask of tables used by pExpr->pRight */ 263 Bitmask prereqAll; /* Bitmask of tables referenced by pExpr */ 264 }; 265 266 /* 267 ** Allowed values of WhereTerm.wtFlags 268 */ 269 #define TERM_DYNAMIC 0x0001 /* Need to call sqlite3ExprDelete(db, pExpr) */ 270 #define TERM_VIRTUAL 0x0002 /* Added by the optimizer. Do not code */ 271 #define TERM_CODED 0x0004 /* This term is already coded */ 272 #define TERM_COPIED 0x0008 /* Has a child */ 273 #define TERM_ORINFO 0x0010 /* Need to free the WhereTerm.u.pOrInfo object */ 274 #define TERM_ANDINFO 0x0020 /* Need to free the WhereTerm.u.pAndInfo obj */ 275 #define TERM_OK 0x0040 /* Used during OR-clause processing */ 276 #define TERM_VNULL 0x0080 /* Manufactured x>NULL or x<=NULL term */ 277 #define TERM_LIKEOPT 0x0100 /* Virtual terms from the LIKE optimization */ 278 #define TERM_LIKECOND 0x0200 /* Conditionally this LIKE operator term */ 279 #define TERM_LIKE 0x0400 /* The original LIKE operator */ 280 #define TERM_IS 0x0800 /* Term.pExpr is an IS operator */ 281 #define TERM_VARSELECT 0x1000 /* Term.pExpr contains a correlated sub-query */ 282 #define TERM_HEURTRUTH 0x2000 /* Heuristic truthProb used */ 283 #ifdef SQLITE_ENABLE_STAT4 284 # define TERM_HIGHTRUTH 0x4000 /* Term excludes few rows */ 285 #else 286 # define TERM_HIGHTRUTH 0 /* Only used with STAT4 */ 287 #endif 288 #define TERM_SLICE 0x8000 /* One slice of a row-value/vector comparison */ 289 290 /* 291 ** An instance of the WhereScan object is used as an iterator for locating 292 ** terms in the WHERE clause that are useful to the query planner. 293 */ 294 struct WhereScan { 295 WhereClause *pOrigWC; /* Original, innermost WhereClause */ 296 WhereClause *pWC; /* WhereClause currently being scanned */ 297 const char *zCollName; /* Required collating sequence, if not NULL */ 298 Expr *pIdxExpr; /* Search for this index expression */ 299 int k; /* Resume scanning at this->pWC->a[this->k] */ 300 u32 opMask; /* Acceptable operators */ 301 char idxaff; /* Must match this affinity, if zCollName!=NULL */ 302 unsigned char iEquiv; /* Current slot in aiCur[] and aiColumn[] */ 303 unsigned char nEquiv; /* Number of entries in aiCur[] and aiColumn[] */ 304 int aiCur[11]; /* Cursors in the equivalence class */ 305 i16 aiColumn[11]; /* Corresponding column number in the eq-class */ 306 }; 307 308 /* 309 ** An instance of the following structure holds all information about a 310 ** WHERE clause. Mostly this is a container for one or more WhereTerms. 311 ** 312 ** Explanation of pOuter: For a WHERE clause of the form 313 ** 314 ** a AND ((b AND c) OR (d AND e)) AND f 315 ** 316 ** There are separate WhereClause objects for the whole clause and for 317 ** the subclauses "(b AND c)" and "(d AND e)". The pOuter field of the 318 ** subclauses points to the WhereClause object for the whole clause. 319 */ 320 struct WhereClause { 321 WhereInfo *pWInfo; /* WHERE clause processing context */ 322 WhereClause *pOuter; /* Outer conjunction */ 323 u8 op; /* Split operator. TK_AND or TK_OR */ 324 u8 hasOr; /* True if any a[].eOperator is WO_OR */ 325 int nTerm; /* Number of terms */ 326 int nSlot; /* Number of entries in a[] */ 327 int nBase; /* Number of terms through the last non-Virtual */ 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 ** This object is a convenience wrapper holding all information needed 387 ** to construct WhereLoop objects for a particular query. 388 */ 389 struct WhereLoopBuilder { 390 WhereInfo *pWInfo; /* Information about this WHERE */ 391 WhereClause *pWC; /* WHERE clause terms */ 392 WhereLoop *pNew; /* Template WhereLoop */ 393 WhereOrSet *pOrSet; /* Record best loops here, if not NULL */ 394 #ifdef SQLITE_ENABLE_STAT4 395 UnpackedRecord *pRec; /* Probe for stat4 (if required) */ 396 int nRecValid; /* Number of valid fields currently in pRec */ 397 #endif 398 unsigned char bldFlags1; /* First set of SQLITE_BLDF_* flags */ 399 unsigned char bldFlags2; /* Second set of SQLITE_BLDF_* flags */ 400 unsigned int iPlanLimit; /* Search limiter */ 401 }; 402 403 /* Allowed values for WhereLoopBuider.bldFlags */ 404 #define SQLITE_BLDF1_INDEXED 0x0001 /* An index is used */ 405 #define SQLITE_BLDF1_UNIQUE 0x0002 /* All keys of a UNIQUE index used */ 406 407 #define SQLITE_BLDF2_2NDPASS 0x0004 /* Second builder pass needed */ 408 409 /* The WhereLoopBuilder.iPlanLimit is used to limit the number of 410 ** index+constraint combinations the query planner will consider for a 411 ** particular query. If this parameter is unlimited, then certain 412 ** pathological queries can spend excess time in the sqlite3WhereBegin() 413 ** routine. The limit is high enough that is should not impact real-world 414 ** queries. 415 ** 416 ** SQLITE_QUERY_PLANNER_LIMIT is the baseline limit. The limit is 417 ** increased by SQLITE_QUERY_PLANNER_LIMIT_INCR before each term of the FROM 418 ** clause is processed, so that every table in a join is guaranteed to be 419 ** able to propose a some index+constraint combinations even if the initial 420 ** baseline limit was exhausted by prior tables of the join. 421 */ 422 #ifndef SQLITE_QUERY_PLANNER_LIMIT 423 # define SQLITE_QUERY_PLANNER_LIMIT 20000 424 #endif 425 #ifndef SQLITE_QUERY_PLANNER_LIMIT_INCR 426 # define SQLITE_QUERY_PLANNER_LIMIT_INCR 1000 427 #endif 428 429 /* 430 ** Each instance of this object records a change to a single node 431 ** in an expression tree to cause that node to point to a column 432 ** of an index rather than an expression or a virtual column. All 433 ** such transformations need to be undone at the end of WHERE clause 434 ** processing. 435 */ 436 typedef struct WhereExprMod WhereExprMod; 437 struct WhereExprMod { 438 WhereExprMod *pNext; /* Next translation on a list of them all */ 439 Expr *pExpr; /* The Expr node that was transformed */ 440 Expr orig; /* Original value of the Expr node */ 441 }; 442 443 /* 444 ** The WHERE clause processing routine has two halves. The 445 ** first part does the start of the WHERE loop and the second 446 ** half does the tail of the WHERE loop. An instance of 447 ** this structure is returned by the first half and passed 448 ** into the second half to give some continuity. 449 ** 450 ** An instance of this object holds the complete state of the query 451 ** planner. 452 */ 453 struct WhereInfo { 454 Parse *pParse; /* Parsing and code generating context */ 455 SrcList *pTabList; /* List of tables in the join */ 456 ExprList *pOrderBy; /* The ORDER BY clause or NULL */ 457 ExprList *pResultSet; /* Result set of the query */ 458 Expr *pWhere; /* The complete WHERE clause */ 459 #ifndef SQLITE_OMIT_VIRTUALTABLE 460 Select *pLimit; /* Used to access LIMIT expr/registers for vtabs */ 461 #endif 462 int aiCurOnePass[2]; /* OP_OpenWrite cursors for the ONEPASS opt */ 463 int iContinue; /* Jump here to continue with next record */ 464 int iBreak; /* Jump here to break out of the loop */ 465 int savedNQueryLoop; /* pParse->nQueryLoop outside the WHERE loop */ 466 u16 wctrlFlags; /* Flags originally passed to sqlite3WhereBegin() */ 467 LogEst iLimit; /* LIMIT if wctrlFlags has WHERE_USE_LIMIT */ 468 u8 nLevel; /* Number of nested loop */ 469 i8 nOBSat; /* Number of ORDER BY terms satisfied by indices */ 470 u8 eOnePass; /* ONEPASS_OFF, or _SINGLE, or _MULTI */ 471 u8 eDistinct; /* One of the WHERE_DISTINCT_* values */ 472 unsigned bDeferredSeek :1; /* Uses OP_DeferredSeek */ 473 unsigned untestedTerms :1; /* Not all WHERE terms resolved by outer loop */ 474 unsigned bOrderedInnerLoop:1;/* True if only the inner-most loop is ordered */ 475 unsigned sorted :1; /* True if really sorted (not just grouped) */ 476 LogEst nRowOut; /* Estimated number of output rows */ 477 int iTop; /* The very beginning of the WHERE loop */ 478 int iEndWhere; /* End of the WHERE clause itself */ 479 WhereLoop *pLoops; /* List of all WhereLoop objects */ 480 WhereExprMod *pExprMods; /* Expression modifications */ 481 Bitmask revMask; /* Mask of ORDER BY terms that need reversing */ 482 WhereClause sWC; /* Decomposition of the WHERE clause */ 483 WhereMaskSet sMaskSet; /* Map cursor numbers to bitmasks */ 484 WhereLevel a[1]; /* Information about each nest loop in WHERE */ 485 }; 486 487 /* 488 ** Private interfaces - callable only by other where.c routines. 489 ** 490 ** where.c: 491 */ 492 Bitmask sqlite3WhereGetMask(WhereMaskSet*,int); 493 #ifdef WHERETRACE_ENABLED 494 void sqlite3WhereClausePrint(WhereClause *pWC); 495 void sqlite3WhereTermPrint(WhereTerm *pTerm, int iTerm); 496 void sqlite3WhereLoopPrint(WhereLoop *p, WhereClause *pWC); 497 #endif 498 WhereTerm *sqlite3WhereFindTerm( 499 WhereClause *pWC, /* The WHERE clause to be searched */ 500 int iCur, /* Cursor number of LHS */ 501 int iColumn, /* Column number of LHS */ 502 Bitmask notReady, /* RHS must not overlap with this mask */ 503 u32 op, /* Mask of WO_xx values describing operator */ 504 Index *pIdx /* Must be compatible with this index, if not NULL */ 505 ); 506 507 /* wherecode.c: */ 508 #ifndef SQLITE_OMIT_EXPLAIN 509 int sqlite3WhereExplainOneScan( 510 Parse *pParse, /* Parse context */ 511 SrcList *pTabList, /* Table list this loop refers to */ 512 WhereLevel *pLevel, /* Scan to write OP_Explain opcode for */ 513 u16 wctrlFlags /* Flags passed to sqlite3WhereBegin() */ 514 ); 515 int sqlite3WhereExplainBloomFilter( 516 const Parse *pParse, /* Parse context */ 517 const WhereInfo *pWInfo, /* WHERE clause */ 518 const WhereLevel *pLevel /* Bloom filter on this level */ 519 ); 520 #else 521 # define sqlite3WhereExplainOneScan(u,v,w,x) 0 522 # define sqlite3WhereExplainBloomFilter(u,v,w) 0 523 #endif /* SQLITE_OMIT_EXPLAIN */ 524 #ifdef SQLITE_ENABLE_STMT_SCANSTATUS 525 void sqlite3WhereAddScanStatus( 526 Vdbe *v, /* Vdbe to add scanstatus entry to */ 527 SrcList *pSrclist, /* FROM clause pLvl reads data from */ 528 WhereLevel *pLvl, /* Level to add scanstatus() entry for */ 529 int addrExplain /* Address of OP_Explain (or 0) */ 530 ); 531 #else 532 # define sqlite3WhereAddScanStatus(a, b, c, d) ((void)d) 533 #endif 534 Bitmask sqlite3WhereCodeOneLoopStart( 535 Parse *pParse, /* Parsing context */ 536 Vdbe *v, /* Prepared statement under construction */ 537 WhereInfo *pWInfo, /* Complete information about the WHERE clause */ 538 int iLevel, /* Which level of pWInfo->a[] should be coded */ 539 WhereLevel *pLevel, /* The current level pointer */ 540 Bitmask notReady /* Which tables are currently available */ 541 ); 542 543 /* whereexpr.c: */ 544 void sqlite3WhereClauseInit(WhereClause*,WhereInfo*); 545 void sqlite3WhereClauseClear(WhereClause*); 546 void sqlite3WhereSplit(WhereClause*,Expr*,u8); 547 void sqlite3WhereAddLimit(WhereClause*, Select*); 548 Bitmask sqlite3WhereExprUsage(WhereMaskSet*, Expr*); 549 Bitmask sqlite3WhereExprUsageNN(WhereMaskSet*, Expr*); 550 Bitmask sqlite3WhereExprListUsage(WhereMaskSet*, ExprList*); 551 void sqlite3WhereExprAnalyze(SrcList*, WhereClause*); 552 void sqlite3WhereTabFuncArgs(Parse*, SrcItem*, WhereClause*); 553 554 555 556 557 558 /* 559 ** Bitmasks for the operators on WhereTerm objects. These are all 560 ** operators that are of interest to the query planner. An 561 ** OR-ed combination of these values can be used when searching for 562 ** particular WhereTerms within a WhereClause. 563 ** 564 ** Value constraints: 565 ** WO_EQ == SQLITE_INDEX_CONSTRAINT_EQ 566 ** WO_LT == SQLITE_INDEX_CONSTRAINT_LT 567 ** WO_LE == SQLITE_INDEX_CONSTRAINT_LE 568 ** WO_GT == SQLITE_INDEX_CONSTRAINT_GT 569 ** WO_GE == SQLITE_INDEX_CONSTRAINT_GE 570 */ 571 #define WO_IN 0x0001 572 #define WO_EQ 0x0002 573 #define WO_LT (WO_EQ<<(TK_LT-TK_EQ)) 574 #define WO_LE (WO_EQ<<(TK_LE-TK_EQ)) 575 #define WO_GT (WO_EQ<<(TK_GT-TK_EQ)) 576 #define WO_GE (WO_EQ<<(TK_GE-TK_EQ)) 577 #define WO_AUX 0x0040 /* Op useful to virtual tables only */ 578 #define WO_IS 0x0080 579 #define WO_ISNULL 0x0100 580 #define WO_OR 0x0200 /* Two or more OR-connected terms */ 581 #define WO_AND 0x0400 /* Two or more AND-connected terms */ 582 #define WO_EQUIV 0x0800 /* Of the form A==B, both columns */ 583 #define WO_NOOP 0x1000 /* This term does not restrict search space */ 584 585 #define WO_ALL 0x1fff /* Mask of all possible WO_* values */ 586 #define WO_SINGLE 0x01ff /* Mask of all non-compound WO_* values */ 587 588 /* 589 ** These are definitions of bits in the WhereLoop.wsFlags field. 590 ** The particular combination of bits in each WhereLoop help to 591 ** determine the algorithm that WhereLoop represents. 592 */ 593 #define WHERE_COLUMN_EQ 0x00000001 /* x=EXPR */ 594 #define WHERE_COLUMN_RANGE 0x00000002 /* x<EXPR and/or x>EXPR */ 595 #define WHERE_COLUMN_IN 0x00000004 /* x IN (...) */ 596 #define WHERE_COLUMN_NULL 0x00000008 /* x IS NULL */ 597 #define WHERE_CONSTRAINT 0x0000000f /* Any of the WHERE_COLUMN_xxx values */ 598 #define WHERE_TOP_LIMIT 0x00000010 /* x<EXPR or x<=EXPR constraint */ 599 #define WHERE_BTM_LIMIT 0x00000020 /* x>EXPR or x>=EXPR constraint */ 600 #define WHERE_BOTH_LIMIT 0x00000030 /* Both x>EXPR and x<EXPR */ 601 #define WHERE_IDX_ONLY 0x00000040 /* Use index only - omit table */ 602 #define WHERE_IPK 0x00000100 /* x is the INTEGER PRIMARY KEY */ 603 #define WHERE_INDEXED 0x00000200 /* WhereLoop.u.btree.pIndex is valid */ 604 #define WHERE_VIRTUALTABLE 0x00000400 /* WhereLoop.u.vtab is valid */ 605 #define WHERE_IN_ABLE 0x00000800 /* Able to support an IN operator */ 606 #define WHERE_ONEROW 0x00001000 /* Selects no more than one row */ 607 #define WHERE_MULTI_OR 0x00002000 /* OR using multiple indices */ 608 #define WHERE_AUTO_INDEX 0x00004000 /* Uses an ephemeral index */ 609 #define WHERE_SKIPSCAN 0x00008000 /* Uses the skip-scan algorithm */ 610 #define WHERE_UNQ_WANTED 0x00010000 /* WHERE_ONEROW would have been helpful*/ 611 #define WHERE_PARTIALIDX 0x00020000 /* The automatic index is partial */ 612 #define WHERE_IN_EARLYOUT 0x00040000 /* Perhaps quit IN loops early */ 613 #define WHERE_BIGNULL_SORT 0x00080000 /* Column nEq of index is BIGNULL */ 614 #define WHERE_IN_SEEKSCAN 0x00100000 /* Seek-scan optimization for IN */ 615 #define WHERE_TRANSCONS 0x00200000 /* Uses a transitive constraint */ 616 #define WHERE_BLOOMFILTER 0x00400000 /* Consider using a Bloom-filter */ 617 #define WHERE_SELFCULL 0x00800000 /* nOut reduced by extra WHERE terms */ 618 #define WHERE_OMIT_OFFSET 0x01000000 /* Set offset counter to zero */ 619 620 #endif /* !defined(SQLITE_WHEREINT_H) */ 621