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 ** Trace output macros 22 */ 23 #if defined(SQLITE_TEST) || defined(SQLITE_DEBUG) 24 /***/ extern int sqlite3WhereTrace; 25 #endif 26 #if defined(SQLITE_DEBUG) \ 27 && (defined(SQLITE_TEST) || defined(SQLITE_ENABLE_WHERETRACE)) 28 # define WHERETRACE(K,X) if(sqlite3WhereTrace&(K)) sqlite3DebugPrintf X 29 # define WHERETRACE_ENABLED 1 30 #else 31 # define WHERETRACE(K,X) 32 #endif 33 34 /* Forward references 35 */ 36 typedef struct WhereClause WhereClause; 37 typedef struct WhereMaskSet WhereMaskSet; 38 typedef struct WhereOrInfo WhereOrInfo; 39 typedef struct WhereAndInfo WhereAndInfo; 40 typedef struct WhereLevel WhereLevel; 41 typedef struct WhereLoop WhereLoop; 42 typedef struct WherePath WherePath; 43 typedef struct WhereTerm WhereTerm; 44 typedef struct WhereLoopBuilder WhereLoopBuilder; 45 typedef struct WhereScan WhereScan; 46 typedef struct WhereOrCost WhereOrCost; 47 typedef struct WhereOrSet WhereOrSet; 48 49 /* 50 ** This object contains information needed to implement a single nested 51 ** loop in WHERE clause. 52 ** 53 ** Contrast this object with WhereLoop. This object describes the 54 ** implementation of the loop. WhereLoop describes the algorithm. 55 ** This object contains a pointer to the WhereLoop algorithm as one of 56 ** its elements. 57 ** 58 ** The WhereInfo object contains a single instance of this object for 59 ** each term in the FROM clause (which is to say, for each of the 60 ** nested loops as implemented). The order of WhereLevel objects determines 61 ** the loop nested order, with WhereInfo.a[0] being the outer loop and 62 ** WhereInfo.a[WhereInfo.nLevel-1] being the inner loop. 63 */ 64 struct WhereLevel { 65 int iLeftJoin; /* Memory cell used to implement LEFT OUTER JOIN */ 66 int iTabCur; /* The VDBE cursor used to access the table */ 67 int iIdxCur; /* The VDBE cursor used to access pIdx */ 68 int addrBrk; /* Jump here to break out of the loop */ 69 int addrNxt; /* Jump here to start the next IN combination */ 70 int addrSkip; /* Jump here for next iteration of skip-scan */ 71 int addrCont; /* Jump here to continue with the next loop cycle */ 72 int addrFirst; /* First instruction of interior of the loop */ 73 int addrBody; /* Beginning of the body of this loop */ 74 int regBignull; /* big-null flag reg. True if a NULL-scan is needed */ 75 int addrBignull; /* Jump here for next part of big-null scan */ 76 #ifndef SQLITE_LIKE_DOESNT_MATCH_BLOBS 77 u32 iLikeRepCntr; /* LIKE range processing counter register (times 2) */ 78 int addrLikeRep; /* LIKE range processing address */ 79 #endif 80 u8 iFrom; /* Which entry in the FROM clause */ 81 u8 op, p3, p5; /* Opcode, P3 & P5 of the opcode that ends the loop */ 82 int p1, p2; /* Operands of the opcode used to end the loop */ 83 union { /* Information that depends on pWLoop->wsFlags */ 84 struct { 85 int nIn; /* Number of entries in aInLoop[] */ 86 struct InLoop { 87 int iCur; /* The VDBE cursor used by this IN operator */ 88 int addrInTop; /* Top of the IN loop */ 89 int iBase; /* Base register of multi-key index record */ 90 int nPrefix; /* Number of prior entires in the key */ 91 u8 eEndLoopOp; /* IN Loop terminator. OP_Next or OP_Prev */ 92 } *aInLoop; /* Information about each nested IN operator */ 93 } in; /* Used when pWLoop->wsFlags&WHERE_IN_ABLE */ 94 Index *pCovidx; /* Possible covering index for WHERE_MULTI_OR */ 95 } u; 96 struct WhereLoop *pWLoop; /* The selected WhereLoop object */ 97 Bitmask notReady; /* FROM entries not usable at this level */ 98 #ifdef SQLITE_ENABLE_STMT_SCANSTATUS 99 int addrVisit; /* Address at which row is visited */ 100 #endif 101 }; 102 103 /* 104 ** Each instance of this object represents an algorithm for evaluating one 105 ** term of a join. Every term of the FROM clause will have at least 106 ** one corresponding WhereLoop object (unless INDEXED BY constraints 107 ** prevent a query solution - which is an error) and many terms of the 108 ** FROM clause will have multiple WhereLoop objects, each describing a 109 ** potential way of implementing that FROM-clause term, together with 110 ** dependencies and cost estimates for using the chosen algorithm. 111 ** 112 ** Query planning consists of building up a collection of these WhereLoop 113 ** objects, then computing a particular sequence of WhereLoop objects, with 114 ** one WhereLoop object per FROM clause term, that satisfy all dependencies 115 ** and that minimize the overall cost. 116 */ 117 struct WhereLoop { 118 Bitmask prereq; /* Bitmask of other loops that must run first */ 119 Bitmask maskSelf; /* Bitmask identifying table iTab */ 120 #ifdef SQLITE_DEBUG 121 char cId; /* Symbolic ID of this loop for debugging use */ 122 #endif 123 u8 iTab; /* Position in FROM clause of table for this loop */ 124 u8 iSortIdx; /* Sorting index number. 0==None */ 125 LogEst rSetup; /* One-time setup cost (ex: create transient index) */ 126 LogEst rRun; /* Cost of running each loop */ 127 LogEst nOut; /* Estimated number of output rows */ 128 union { 129 struct { /* Information for internal btree tables */ 130 u16 nEq; /* Number of equality constraints */ 131 u16 nBtm; /* Size of BTM vector */ 132 u16 nTop; /* Size of TOP vector */ 133 u16 nDistinctCol; /* Index columns used to sort for DISTINCT */ 134 Index *pIndex; /* Index used, or NULL */ 135 } btree; 136 struct { /* Information for virtual tables */ 137 int idxNum; /* Index number */ 138 u8 needFree; /* True if sqlite3_free(idxStr) is needed */ 139 i8 isOrdered; /* True if satisfies ORDER BY */ 140 u16 omitMask; /* Terms that may be omitted */ 141 char *idxStr; /* Index identifier string */ 142 } vtab; 143 } u; 144 u32 wsFlags; /* WHERE_* flags describing the plan */ 145 u16 nLTerm; /* Number of entries in aLTerm[] */ 146 u16 nSkip; /* Number of NULL aLTerm[] entries */ 147 /**** whereLoopXfer() copies fields above ***********************/ 148 # define WHERE_LOOP_XFER_SZ offsetof(WhereLoop,nLSlot) 149 u16 nLSlot; /* Number of slots allocated for aLTerm[] */ 150 WhereTerm **aLTerm; /* WhereTerms used */ 151 WhereLoop *pNextLoop; /* Next WhereLoop object in the WhereClause */ 152 WhereTerm *aLTermSpace[3]; /* Initial aLTerm[] space */ 153 }; 154 155 /* This object holds the prerequisites and the cost of running a 156 ** subquery on one operand of an OR operator in the WHERE clause. 157 ** See WhereOrSet for additional information 158 */ 159 struct WhereOrCost { 160 Bitmask prereq; /* Prerequisites */ 161 LogEst rRun; /* Cost of running this subquery */ 162 LogEst nOut; /* Number of outputs for this subquery */ 163 }; 164 165 /* The WhereOrSet object holds a set of possible WhereOrCosts that 166 ** correspond to the subquery(s) of OR-clause processing. Only the 167 ** best N_OR_COST elements are retained. 168 */ 169 #define N_OR_COST 3 170 struct WhereOrSet { 171 u16 n; /* Number of valid a[] entries */ 172 WhereOrCost a[N_OR_COST]; /* Set of best costs */ 173 }; 174 175 /* 176 ** Each instance of this object holds a sequence of WhereLoop objects 177 ** that implement some or all of a query plan. 178 ** 179 ** Think of each WhereLoop object as a node in a graph with arcs 180 ** showing dependencies and costs for travelling between nodes. (That is 181 ** not a completely accurate description because WhereLoop costs are a 182 ** vector, not a scalar, and because dependencies are many-to-one, not 183 ** one-to-one as are graph nodes. But it is a useful visualization aid.) 184 ** Then a WherePath object is a path through the graph that visits some 185 ** or all of the WhereLoop objects once. 186 ** 187 ** The "solver" works by creating the N best WherePath objects of length 188 ** 1. Then using those as a basis to compute the N best WherePath objects 189 ** of length 2. And so forth until the length of WherePaths equals the 190 ** number of nodes in the FROM clause. The best (lowest cost) WherePath 191 ** at the end is the chosen query plan. 192 */ 193 struct WherePath { 194 Bitmask maskLoop; /* Bitmask of all WhereLoop objects in this path */ 195 Bitmask revLoop; /* aLoop[]s that should be reversed for ORDER BY */ 196 LogEst nRow; /* Estimated number of rows generated by this path */ 197 LogEst rCost; /* Total cost of this path */ 198 LogEst rUnsorted; /* Total cost of this path ignoring sorting costs */ 199 i8 isOrdered; /* No. of ORDER BY terms satisfied. -1 for unknown */ 200 WhereLoop **aLoop; /* Array of WhereLoop objects implementing this path */ 201 }; 202 203 /* 204 ** The query generator uses an array of instances of this structure to 205 ** help it analyze the subexpressions of the WHERE clause. Each WHERE 206 ** clause subexpression is separated from the others by AND operators, 207 ** usually, or sometimes subexpressions separated by OR. 208 ** 209 ** All WhereTerms are collected into a single WhereClause structure. 210 ** The following identity holds: 211 ** 212 ** WhereTerm.pWC->a[WhereTerm.idx] == WhereTerm 213 ** 214 ** When a term is of the form: 215 ** 216 ** X <op> <expr> 217 ** 218 ** where X is a column name and <op> is one of certain operators, 219 ** then WhereTerm.leftCursor and WhereTerm.u.leftColumn record the 220 ** cursor number and column number for X. WhereTerm.eOperator records 221 ** the <op> using a bitmask encoding defined by WO_xxx below. The 222 ** use of a bitmask encoding for the operator allows us to search 223 ** quickly for terms that match any of several different operators. 224 ** 225 ** A WhereTerm might also be two or more subterms connected by OR: 226 ** 227 ** (t1.X <op> <expr>) OR (t1.Y <op> <expr>) OR .... 228 ** 229 ** In this second case, wtFlag has the TERM_ORINFO bit set and eOperator==WO_OR 230 ** and the WhereTerm.u.pOrInfo field points to auxiliary information that 231 ** is collected about the OR clause. 232 ** 233 ** If a term in the WHERE clause does not match either of the two previous 234 ** categories, then eOperator==0. The WhereTerm.pExpr field is still set 235 ** to the original subexpression content and wtFlags is set up appropriately 236 ** but no other fields in the WhereTerm object are meaningful. 237 ** 238 ** When eOperator!=0, prereqRight and prereqAll record sets of cursor numbers, 239 ** but they do so indirectly. A single WhereMaskSet structure translates 240 ** cursor number into bits and the translated bit is stored in the prereq 241 ** fields. The translation is used in order to maximize the number of 242 ** bits that will fit in a Bitmask. The VDBE cursor numbers might be 243 ** spread out over the non-negative integers. For example, the cursor 244 ** numbers might be 3, 8, 9, 10, 20, 23, 41, and 45. The WhereMaskSet 245 ** translates these sparse cursor numbers into consecutive integers 246 ** beginning with 0 in order to make the best possible use of the available 247 ** bits in the Bitmask. So, in the example above, the cursor numbers 248 ** would be mapped into integers 0 through 7. 249 ** 250 ** The number of terms in a join is limited by the number of bits 251 ** in prereqRight and prereqAll. The default is 64 bits, hence SQLite 252 ** is only able to process joins with 64 or fewer tables. 253 */ 254 struct WhereTerm { 255 Expr *pExpr; /* Pointer to the subexpression that is this term */ 256 WhereClause *pWC; /* The clause this term is part of */ 257 LogEst truthProb; /* Probability of truth for this expression */ 258 u16 wtFlags; /* TERM_xxx bit flags. See below */ 259 u16 eOperator; /* A WO_xx value describing <op> */ 260 u8 nChild; /* Number of children that must disable us */ 261 u8 eMatchOp; /* Op for vtab MATCH/LIKE/GLOB/REGEXP terms */ 262 int iParent; /* Disable pWC->a[iParent] when this term disabled */ 263 int leftCursor; /* Cursor number of X in "X <op> <expr>" */ 264 int iField; /* Field in (?,?,?) IN (SELECT...) vector */ 265 union { 266 int leftColumn; /* Column number of X in "X <op> <expr>" */ 267 WhereOrInfo *pOrInfo; /* Extra information if (eOperator & WO_OR)!=0 */ 268 WhereAndInfo *pAndInfo; /* Extra information if (eOperator& WO_AND)!=0 */ 269 } u; 270 Bitmask prereqRight; /* Bitmask of tables used by pExpr->pRight */ 271 Bitmask prereqAll; /* Bitmask of tables referenced by pExpr */ 272 }; 273 274 /* 275 ** Allowed values of WhereTerm.wtFlags 276 */ 277 #define TERM_DYNAMIC 0x0001 /* Need to call sqlite3ExprDelete(db, pExpr) */ 278 #define TERM_VIRTUAL 0x0002 /* Added by the optimizer. Do not code */ 279 #define TERM_CODED 0x0004 /* This term is already coded */ 280 #define TERM_COPIED 0x0008 /* Has a child */ 281 #define TERM_ORINFO 0x0010 /* Need to free the WhereTerm.u.pOrInfo object */ 282 #define TERM_ANDINFO 0x0020 /* Need to free the WhereTerm.u.pAndInfo obj */ 283 #define TERM_OR_OK 0x0040 /* Used during OR-clause processing */ 284 #ifdef SQLITE_ENABLE_STAT4 285 # define TERM_VNULL 0x0080 /* Manufactured x>NULL or x<=NULL term */ 286 #else 287 # define TERM_VNULL 0x0000 /* Disabled if not using stat4 */ 288 #endif 289 #define TERM_LIKEOPT 0x0100 /* Virtual terms from the LIKE optimization */ 290 #define TERM_LIKECOND 0x0200 /* Conditionally this LIKE operator term */ 291 #define TERM_LIKE 0x0400 /* The original LIKE operator */ 292 #define TERM_IS 0x0800 /* Term.pExpr is an IS operator */ 293 #define TERM_VARSELECT 0x1000 /* Term.pExpr contains a correlated sub-query */ 294 #define TERM_HEURTRUTH 0x2000 /* Heuristic truthProb used */ 295 #ifdef SQLITE_ENABLE_STAT4 296 # define TERM_HIGHTRUTH 0x4000 /* Term excludes few rows */ 297 #else 298 # define TERM_HIGHTRUTH 0 /* Only used with STAT4 */ 299 #endif 300 301 /* 302 ** An instance of the WhereScan object is used as an iterator for locating 303 ** terms in the WHERE clause that are useful to the query planner. 304 */ 305 struct WhereScan { 306 WhereClause *pOrigWC; /* Original, innermost WhereClause */ 307 WhereClause *pWC; /* WhereClause currently being scanned */ 308 const char *zCollName; /* Required collating sequence, if not NULL */ 309 Expr *pIdxExpr; /* Search for this index expression */ 310 char idxaff; /* Must match this affinity, if zCollName!=NULL */ 311 unsigned char nEquiv; /* Number of entries in aEquiv[] */ 312 unsigned char iEquiv; /* Next unused slot in aEquiv[] */ 313 u32 opMask; /* Acceptable operators */ 314 int k; /* Resume scanning at this->pWC->a[this->k] */ 315 int aiCur[11]; /* Cursors in the equivalence class */ 316 i16 aiColumn[11]; /* Corresponding column number in the eq-class */ 317 }; 318 319 /* 320 ** An instance of the following structure holds all information about a 321 ** WHERE clause. Mostly this is a container for one or more WhereTerms. 322 ** 323 ** Explanation of pOuter: For a WHERE clause of the form 324 ** 325 ** a AND ((b AND c) OR (d AND e)) AND f 326 ** 327 ** There are separate WhereClause objects for the whole clause and for 328 ** the subclauses "(b AND c)" and "(d AND e)". The pOuter field of the 329 ** subclauses points to the WhereClause object for the whole clause. 330 */ 331 struct WhereClause { 332 WhereInfo *pWInfo; /* WHERE clause processing context */ 333 WhereClause *pOuter; /* Outer conjunction */ 334 u8 op; /* Split operator. TK_AND or TK_OR */ 335 u8 hasOr; /* True if any a[].eOperator is WO_OR */ 336 int nTerm; /* Number of terms */ 337 int nSlot; /* Number of entries in a[] */ 338 WhereTerm *a; /* Each a[] describes a term of the WHERE cluase */ 339 #if defined(SQLITE_SMALL_STACK) 340 WhereTerm aStatic[1]; /* Initial static space for a[] */ 341 #else 342 WhereTerm aStatic[8]; /* Initial static space for a[] */ 343 #endif 344 }; 345 346 /* 347 ** A WhereTerm with eOperator==WO_OR has its u.pOrInfo pointer set to 348 ** a dynamically allocated instance of the following structure. 349 */ 350 struct WhereOrInfo { 351 WhereClause wc; /* Decomposition into subterms */ 352 Bitmask indexable; /* Bitmask of all indexable tables in the clause */ 353 }; 354 355 /* 356 ** A WhereTerm with eOperator==WO_AND has its u.pAndInfo pointer set to 357 ** a dynamically allocated instance of the following structure. 358 */ 359 struct WhereAndInfo { 360 WhereClause wc; /* The subexpression broken out */ 361 }; 362 363 /* 364 ** An instance of the following structure keeps track of a mapping 365 ** between VDBE cursor numbers and bits of the bitmasks in WhereTerm. 366 ** 367 ** The VDBE cursor numbers are small integers contained in 368 ** SrcList_item.iCursor and Expr.iTable fields. For any given WHERE 369 ** clause, the cursor numbers might not begin with 0 and they might 370 ** contain gaps in the numbering sequence. But we want to make maximum 371 ** use of the bits in our bitmasks. This structure provides a mapping 372 ** from the sparse cursor numbers into consecutive integers beginning 373 ** with 0. 374 ** 375 ** If WhereMaskSet.ix[A]==B it means that The A-th bit of a Bitmask 376 ** corresponds VDBE cursor number B. The A-th bit of a bitmask is 1<<A. 377 ** 378 ** For example, if the WHERE clause expression used these VDBE 379 ** cursors: 4, 5, 8, 29, 57, 73. Then the WhereMaskSet structure 380 ** would map those cursor numbers into bits 0 through 5. 381 ** 382 ** Note that the mapping is not necessarily ordered. In the example 383 ** above, the mapping might go like this: 4->3, 5->1, 8->2, 29->0, 384 ** 57->5, 73->4. Or one of 719 other combinations might be used. It 385 ** does not really matter. What is important is that sparse cursor 386 ** numbers all get mapped into bit numbers that begin with 0 and contain 387 ** no gaps. 388 */ 389 struct WhereMaskSet { 390 int bVarSelect; /* Used by sqlite3WhereExprUsage() */ 391 int n; /* Number of assigned cursor values */ 392 int ix[BMS]; /* Cursor assigned to each bit */ 393 }; 394 395 /* 396 ** Initialize a WhereMaskSet object 397 */ 398 #define initMaskSet(P) (P)->n=0 399 400 /* 401 ** This object is a convenience wrapper holding all information needed 402 ** to construct WhereLoop objects for a particular query. 403 */ 404 struct WhereLoopBuilder { 405 WhereInfo *pWInfo; /* Information about this WHERE */ 406 WhereClause *pWC; /* WHERE clause terms */ 407 ExprList *pOrderBy; /* ORDER BY clause */ 408 WhereLoop *pNew; /* Template WhereLoop */ 409 WhereOrSet *pOrSet; /* Record best loops here, if not NULL */ 410 #ifdef SQLITE_ENABLE_STAT4 411 UnpackedRecord *pRec; /* Probe for stat4 (if required) */ 412 int nRecValid; /* Number of valid fields currently in pRec */ 413 #endif 414 unsigned char bldFlags1; /* First set of SQLITE_BLDF_* flags */ 415 unsigned char bldFlags2; /* Second set of SQLITE_BLDF_* flags */ 416 unsigned int iPlanLimit; /* Search limiter */ 417 }; 418 419 /* Allowed values for WhereLoopBuider.bldFlags */ 420 #define SQLITE_BLDF1_INDEXED 0x0001 /* An index is used */ 421 #define SQLITE_BLDF1_UNIQUE 0x0002 /* All keys of a UNIQUE index used */ 422 423 #define SQLITE_BLDF2_2NDPASS 0x0004 /* Second builder pass needed */ 424 425 /* The WhereLoopBuilder.iPlanLimit is used to limit the number of 426 ** index+constraint combinations the query planner will consider for a 427 ** particular query. If this parameter is unlimited, then certain 428 ** pathological queries can spend excess time in the sqlite3WhereBegin() 429 ** routine. The limit is high enough that is should not impact real-world 430 ** queries. 431 ** 432 ** SQLITE_QUERY_PLANNER_LIMIT is the baseline limit. The limit is 433 ** increased by SQLITE_QUERY_PLANNER_LIMIT_INCR before each term of the FROM 434 ** clause is processed, so that every table in a join is guaranteed to be 435 ** able to propose a some index+constraint combinations even if the initial 436 ** baseline limit was exhausted by prior tables of the join. 437 */ 438 #ifndef SQLITE_QUERY_PLANNER_LIMIT 439 # define SQLITE_QUERY_PLANNER_LIMIT 20000 440 #endif 441 #ifndef SQLITE_QUERY_PLANNER_LIMIT_INCR 442 # define SQLITE_QUERY_PLANNER_LIMIT_INCR 1000 443 #endif 444 445 /* 446 ** Each instance of this object records a change to a single node 447 ** in an expression tree to cause that node to point to a column 448 ** of an index rather than an expression or a virtual column. All 449 ** such transformations need to be undone at the end of WHERE clause 450 ** processing. 451 */ 452 typedef struct WhereExprMod WhereExprMod; 453 struct WhereExprMod { 454 WhereExprMod *pNext; /* Next translation on a list of them all */ 455 Expr *pExpr; /* The Expr node that was transformed */ 456 Expr orig; /* Original value of the Expr node */ 457 }; 458 459 /* 460 ** The WHERE clause processing routine has two halves. The 461 ** first part does the start of the WHERE loop and the second 462 ** half does the tail of the WHERE loop. An instance of 463 ** this structure is returned by the first half and passed 464 ** into the second half to give some continuity. 465 ** 466 ** An instance of this object holds the complete state of the query 467 ** planner. 468 */ 469 struct WhereInfo { 470 Parse *pParse; /* Parsing and code generating context */ 471 SrcList *pTabList; /* List of tables in the join */ 472 ExprList *pOrderBy; /* The ORDER BY clause or NULL */ 473 ExprList *pResultSet; /* Result set of the query */ 474 Expr *pWhere; /* The complete WHERE clause */ 475 int aiCurOnePass[2]; /* OP_OpenWrite cursors for the ONEPASS opt */ 476 int iContinue; /* Jump here to continue with next record */ 477 int iBreak; /* Jump here to break out of the loop */ 478 int savedNQueryLoop; /* pParse->nQueryLoop outside the WHERE loop */ 479 u16 wctrlFlags; /* Flags originally passed to sqlite3WhereBegin() */ 480 LogEst iLimit; /* LIMIT if wctrlFlags has WHERE_USE_LIMIT */ 481 u8 nLevel; /* Number of nested loop */ 482 i8 nOBSat; /* Number of ORDER BY terms satisfied by indices */ 483 u8 eOnePass; /* ONEPASS_OFF, or _SINGLE, or _MULTI */ 484 u8 eDistinct; /* One of the WHERE_DISTINCT_* values */ 485 unsigned bDeferredSeek :1; /* Uses OP_DeferredSeek */ 486 unsigned untestedTerms :1; /* Not all WHERE terms resolved by outer loop */ 487 unsigned bOrderedInnerLoop:1;/* True if only the inner-most loop is ordered */ 488 unsigned sorted :1; /* True if really sorted (not just grouped) */ 489 LogEst nRowOut; /* Estimated number of output rows */ 490 int iTop; /* The very beginning of the WHERE loop */ 491 WhereLoop *pLoops; /* List of all WhereLoop objects */ 492 WhereExprMod *pExprMods; /* Expression modifications */ 493 Bitmask revMask; /* Mask of ORDER BY terms that need reversing */ 494 WhereClause sWC; /* Decomposition of the WHERE clause */ 495 WhereMaskSet sMaskSet; /* Map cursor numbers to bitmasks */ 496 WhereLevel a[1]; /* Information about each nest loop in WHERE */ 497 }; 498 499 /* 500 ** Private interfaces - callable only by other where.c routines. 501 ** 502 ** where.c: 503 */ 504 Bitmask sqlite3WhereGetMask(WhereMaskSet*,int); 505 #ifdef WHERETRACE_ENABLED 506 void sqlite3WhereClausePrint(WhereClause *pWC); 507 void sqlite3WhereTermPrint(WhereTerm *pTerm, int iTerm); 508 void sqlite3WhereLoopPrint(WhereLoop *p, WhereClause *pWC); 509 #endif 510 WhereTerm *sqlite3WhereFindTerm( 511 WhereClause *pWC, /* The WHERE clause to be searched */ 512 int iCur, /* Cursor number of LHS */ 513 int iColumn, /* Column number of LHS */ 514 Bitmask notReady, /* RHS must not overlap with this mask */ 515 u32 op, /* Mask of WO_xx values describing operator */ 516 Index *pIdx /* Must be compatible with this index, if not NULL */ 517 ); 518 519 /* wherecode.c: */ 520 #ifndef SQLITE_OMIT_EXPLAIN 521 int sqlite3WhereExplainOneScan( 522 Parse *pParse, /* Parse context */ 523 SrcList *pTabList, /* Table list this loop refers to */ 524 WhereLevel *pLevel, /* Scan to write OP_Explain opcode for */ 525 u16 wctrlFlags /* Flags passed to sqlite3WhereBegin() */ 526 ); 527 #else 528 # define sqlite3WhereExplainOneScan(u,v,w,x) 0 529 #endif /* SQLITE_OMIT_EXPLAIN */ 530 #ifdef SQLITE_ENABLE_STMT_SCANSTATUS 531 void sqlite3WhereAddScanStatus( 532 Vdbe *v, /* Vdbe to add scanstatus entry to */ 533 SrcList *pSrclist, /* FROM clause pLvl reads data from */ 534 WhereLevel *pLvl, /* Level to add scanstatus() entry for */ 535 int addrExplain /* Address of OP_Explain (or 0) */ 536 ); 537 #else 538 # define sqlite3WhereAddScanStatus(a, b, c, d) ((void)d) 539 #endif 540 Bitmask sqlite3WhereCodeOneLoopStart( 541 Parse *pParse, /* Parsing context */ 542 Vdbe *v, /* Prepared statement under construction */ 543 WhereInfo *pWInfo, /* Complete information about the WHERE clause */ 544 int iLevel, /* Which level of pWInfo->a[] should be coded */ 545 WhereLevel *pLevel, /* The current level pointer */ 546 Bitmask notReady /* Which tables are currently available */ 547 ); 548 549 /* whereexpr.c: */ 550 void sqlite3WhereClauseInit(WhereClause*,WhereInfo*); 551 void sqlite3WhereClauseClear(WhereClause*); 552 void sqlite3WhereSplit(WhereClause*,Expr*,u8); 553 Bitmask sqlite3WhereExprUsage(WhereMaskSet*, Expr*); 554 Bitmask sqlite3WhereExprUsageNN(WhereMaskSet*, Expr*); 555 Bitmask sqlite3WhereExprListUsage(WhereMaskSet*, ExprList*); 556 void sqlite3WhereExprAnalyze(SrcList*, WhereClause*); 557 void sqlite3WhereTabFuncArgs(Parse*, struct SrcList_item*, WhereClause*); 558 559 560 561 562 563 /* 564 ** Bitmasks for the operators on WhereTerm objects. These are all 565 ** operators that are of interest to the query planner. An 566 ** OR-ed combination of these values can be used when searching for 567 ** particular WhereTerms within a WhereClause. 568 ** 569 ** Value constraints: 570 ** WO_EQ == SQLITE_INDEX_CONSTRAINT_EQ 571 ** WO_LT == SQLITE_INDEX_CONSTRAINT_LT 572 ** WO_LE == SQLITE_INDEX_CONSTRAINT_LE 573 ** WO_GT == SQLITE_INDEX_CONSTRAINT_GT 574 ** WO_GE == SQLITE_INDEX_CONSTRAINT_GE 575 */ 576 #define WO_IN 0x0001 577 #define WO_EQ 0x0002 578 #define WO_LT (WO_EQ<<(TK_LT-TK_EQ)) 579 #define WO_LE (WO_EQ<<(TK_LE-TK_EQ)) 580 #define WO_GT (WO_EQ<<(TK_GT-TK_EQ)) 581 #define WO_GE (WO_EQ<<(TK_GE-TK_EQ)) 582 #define WO_AUX 0x0040 /* Op useful to virtual tables only */ 583 #define WO_IS 0x0080 584 #define WO_ISNULL 0x0100 585 #define WO_OR 0x0200 /* Two or more OR-connected terms */ 586 #define WO_AND 0x0400 /* Two or more AND-connected terms */ 587 #define WO_EQUIV 0x0800 /* Of the form A==B, both columns */ 588 #define WO_NOOP 0x1000 /* This term does not restrict search space */ 589 590 #define WO_ALL 0x1fff /* Mask of all possible WO_* values */ 591 #define WO_SINGLE 0x01ff /* Mask of all non-compound WO_* values */ 592 593 /* 594 ** These are definitions of bits in the WhereLoop.wsFlags field. 595 ** The particular combination of bits in each WhereLoop help to 596 ** determine the algorithm that WhereLoop represents. 597 */ 598 #define WHERE_COLUMN_EQ 0x00000001 /* x=EXPR */ 599 #define WHERE_COLUMN_RANGE 0x00000002 /* x<EXPR and/or x>EXPR */ 600 #define WHERE_COLUMN_IN 0x00000004 /* x IN (...) */ 601 #define WHERE_COLUMN_NULL 0x00000008 /* x IS NULL */ 602 #define WHERE_CONSTRAINT 0x0000000f /* Any of the WHERE_COLUMN_xxx values */ 603 #define WHERE_TOP_LIMIT 0x00000010 /* x<EXPR or x<=EXPR constraint */ 604 #define WHERE_BTM_LIMIT 0x00000020 /* x>EXPR or x>=EXPR constraint */ 605 #define WHERE_BOTH_LIMIT 0x00000030 /* Both x>EXPR and x<EXPR */ 606 #define WHERE_IDX_ONLY 0x00000040 /* Use index only - omit table */ 607 #define WHERE_IPK 0x00000100 /* x is the INTEGER PRIMARY KEY */ 608 #define WHERE_INDEXED 0x00000200 /* WhereLoop.u.btree.pIndex is valid */ 609 #define WHERE_VIRTUALTABLE 0x00000400 /* WhereLoop.u.vtab is valid */ 610 #define WHERE_IN_ABLE 0x00000800 /* Able to support an IN operator */ 611 #define WHERE_ONEROW 0x00001000 /* Selects no more than one row */ 612 #define WHERE_MULTI_OR 0x00002000 /* OR using multiple indices */ 613 #define WHERE_AUTO_INDEX 0x00004000 /* Uses an ephemeral index */ 614 #define WHERE_SKIPSCAN 0x00008000 /* Uses the skip-scan algorithm */ 615 #define WHERE_UNQ_WANTED 0x00010000 /* WHERE_ONEROW would have been helpful*/ 616 #define WHERE_PARTIALIDX 0x00020000 /* The automatic index is partial */ 617 #define WHERE_IN_EARLYOUT 0x00040000 /* Perhaps quit IN loops early */ 618 #define WHERE_BIGNULL_SORT 0x00080000 /* Column nEq of index is BIGNULL */ 619 620 #endif /* !defined(SQLITE_WHEREINT_H) */ 621