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 typedef struct WhereMemBlock WhereMemBlock; 36 typedef struct WhereRightJoin WhereRightJoin; 37 38 /* 39 ** This object is a header on a block of allocated memory that will be 40 ** automatically freed when its WInfo oject is destructed. 41 */ 42 struct WhereMemBlock { 43 WhereMemBlock *pNext; /* Next block in the chain */ 44 u64 sz; /* Bytes of space */ 45 }; 46 47 /* 48 ** Extra information attached to a WhereLevel that is a RIGHT JOIN. 49 */ 50 struct WhereRightJoin { 51 int iMatch; /* Cursor used to determine prior matched rows */ 52 int regBloom; /* Bloom filter for iRJMatch */ 53 int regReturn; /* Return register for the interior subroutine */ 54 int addrSubrtn; /* Starting address for the interior subroutine */ 55 int endSubrtn; /* The last opcode in the interior subroutine */ 56 }; 57 58 /* 59 ** This object contains information needed to implement a single nested 60 ** loop in WHERE clause. 61 ** 62 ** Contrast this object with WhereLoop. This object describes the 63 ** implementation of the loop. WhereLoop describes the algorithm. 64 ** This object contains a pointer to the WhereLoop algorithm as one of 65 ** its elements. 66 ** 67 ** The WhereInfo object contains a single instance of this object for 68 ** each term in the FROM clause (which is to say, for each of the 69 ** nested loops as implemented). The order of WhereLevel objects determines 70 ** the loop nested order, with WhereInfo.a[0] being the outer loop and 71 ** WhereInfo.a[WhereInfo.nLevel-1] being the inner loop. 72 */ 73 struct WhereLevel { 74 int iLeftJoin; /* Memory cell used to implement LEFT OUTER JOIN */ 75 int iTabCur; /* The VDBE cursor used to access the table */ 76 int iIdxCur; /* The VDBE cursor used to access pIdx */ 77 int addrBrk; /* Jump here to break out of the loop */ 78 int addrNxt; /* Jump here to start the next IN combination */ 79 int addrSkip; /* Jump here for next iteration of skip-scan */ 80 int addrCont; /* Jump here to continue with the next loop cycle */ 81 int addrFirst; /* First instruction of interior of the loop */ 82 int addrBody; /* Beginning of the body of this loop */ 83 int regBignull; /* big-null flag reg. True if a NULL-scan is needed */ 84 int addrBignull; /* Jump here for next part of big-null scan */ 85 #ifndef SQLITE_LIKE_DOESNT_MATCH_BLOBS 86 u32 iLikeRepCntr; /* LIKE range processing counter register (times 2) */ 87 int addrLikeRep; /* LIKE range processing address */ 88 #endif 89 int regFilter; /* Bloom filter */ 90 WhereRightJoin *pRJ; /* Extra information for RIGHT JOIN */ 91 u8 iFrom; /* Which entry in the FROM clause */ 92 u8 op, p3, p5; /* Opcode, P3 & P5 of the opcode that ends the loop */ 93 int p1, p2; /* Operands of the opcode used to end the loop */ 94 union { /* Information that depends on pWLoop->wsFlags */ 95 struct { 96 int nIn; /* Number of entries in aInLoop[] */ 97 struct InLoop { 98 int iCur; /* The VDBE cursor used by this IN operator */ 99 int addrInTop; /* Top of the IN loop */ 100 int iBase; /* Base register of multi-key index record */ 101 int nPrefix; /* Number of prior entires in the key */ 102 u8 eEndLoopOp; /* IN Loop terminator. OP_Next or OP_Prev */ 103 } *aInLoop; /* Information about each nested IN operator */ 104 } in; /* Used when pWLoop->wsFlags&WHERE_IN_ABLE */ 105 Index *pCoveringIdx; /* Possible covering index for WHERE_MULTI_OR */ 106 } u; 107 struct WhereLoop *pWLoop; /* The selected WhereLoop object */ 108 Bitmask notReady; /* FROM entries not usable at this level */ 109 #ifdef SQLITE_ENABLE_STMT_SCANSTATUS 110 int addrVisit; /* Address at which row is visited */ 111 #endif 112 }; 113 114 /* 115 ** Each instance of this object represents an algorithm for evaluating one 116 ** term of a join. Every term of the FROM clause will have at least 117 ** one corresponding WhereLoop object (unless INDEXED BY constraints 118 ** prevent a query solution - which is an error) and many terms of the 119 ** FROM clause will have multiple WhereLoop objects, each describing a 120 ** potential way of implementing that FROM-clause term, together with 121 ** dependencies and cost estimates for using the chosen algorithm. 122 ** 123 ** Query planning consists of building up a collection of these WhereLoop 124 ** objects, then computing a particular sequence of WhereLoop objects, with 125 ** one WhereLoop object per FROM clause term, that satisfy all dependencies 126 ** and that minimize the overall cost. 127 */ 128 struct WhereLoop { 129 Bitmask prereq; /* Bitmask of other loops that must run first */ 130 Bitmask maskSelf; /* Bitmask identifying table iTab */ 131 #ifdef SQLITE_DEBUG 132 char cId; /* Symbolic ID of this loop for debugging use */ 133 #endif 134 u8 iTab; /* Position in FROM clause of table for this loop */ 135 u8 iSortIdx; /* Sorting index number. 0==None */ 136 LogEst rSetup; /* One-time setup cost (ex: create transient index) */ 137 LogEst rRun; /* Cost of running each loop */ 138 LogEst nOut; /* Estimated number of output rows */ 139 union { 140 struct { /* Information for internal btree tables */ 141 u16 nEq; /* Number of equality constraints */ 142 u16 nBtm; /* Size of BTM vector */ 143 u16 nTop; /* Size of TOP vector */ 144 u16 nDistinctCol; /* Index columns used to sort for DISTINCT */ 145 Index *pIndex; /* Index used, or NULL */ 146 } btree; 147 struct { /* Information for virtual tables */ 148 int idxNum; /* Index number */ 149 u32 needFree : 1; /* True if sqlite3_free(idxStr) is needed */ 150 u32 bOmitOffset : 1; /* True to let virtual table handle offset */ 151 i8 isOrdered; /* True if satisfies ORDER BY */ 152 u16 omitMask; /* Terms that may be omitted */ 153 char *idxStr; /* Index identifier string */ 154 u32 mHandleIn; /* Terms to handle as IN(...) instead of == */ 155 } vtab; 156 } u; 157 u32 wsFlags; /* WHERE_* flags describing the plan */ 158 u16 nLTerm; /* Number of entries in aLTerm[] */ 159 u16 nSkip; /* Number of NULL aLTerm[] entries */ 160 /**** whereLoopXfer() copies fields above ***********************/ 161 # define WHERE_LOOP_XFER_SZ offsetof(WhereLoop,nLSlot) 162 u16 nLSlot; /* Number of slots allocated for aLTerm[] */ 163 WhereTerm **aLTerm; /* WhereTerms used */ 164 WhereLoop *pNextLoop; /* Next WhereLoop object in the WhereClause */ 165 WhereTerm *aLTermSpace[3]; /* Initial aLTerm[] space */ 166 }; 167 168 /* This object holds the prerequisites and the cost of running a 169 ** subquery on one operand of an OR operator in the WHERE clause. 170 ** See WhereOrSet for additional information 171 */ 172 struct WhereOrCost { 173 Bitmask prereq; /* Prerequisites */ 174 LogEst rRun; /* Cost of running this subquery */ 175 LogEst nOut; /* Number of outputs for this subquery */ 176 }; 177 178 /* The WhereOrSet object holds a set of possible WhereOrCosts that 179 ** correspond to the subquery(s) of OR-clause processing. Only the 180 ** best N_OR_COST elements are retained. 181 */ 182 #define N_OR_COST 3 183 struct WhereOrSet { 184 u16 n; /* Number of valid a[] entries */ 185 WhereOrCost a[N_OR_COST]; /* Set of best costs */ 186 }; 187 188 /* 189 ** Each instance of this object holds a sequence of WhereLoop objects 190 ** that implement some or all of a query plan. 191 ** 192 ** Think of each WhereLoop object as a node in a graph with arcs 193 ** showing dependencies and costs for travelling between nodes. (That is 194 ** not a completely accurate description because WhereLoop costs are a 195 ** vector, not a scalar, and because dependencies are many-to-one, not 196 ** one-to-one as are graph nodes. But it is a useful visualization aid.) 197 ** Then a WherePath object is a path through the graph that visits some 198 ** or all of the WhereLoop objects once. 199 ** 200 ** The "solver" works by creating the N best WherePath objects of length 201 ** 1. Then using those as a basis to compute the N best WherePath objects 202 ** of length 2. And so forth until the length of WherePaths equals the 203 ** number of nodes in the FROM clause. The best (lowest cost) WherePath 204 ** at the end is the chosen query plan. 205 */ 206 struct WherePath { 207 Bitmask maskLoop; /* Bitmask of all WhereLoop objects in this path */ 208 Bitmask revLoop; /* aLoop[]s that should be reversed for ORDER BY */ 209 LogEst nRow; /* Estimated number of rows generated by this path */ 210 LogEst rCost; /* Total cost of this path */ 211 LogEst rUnsorted; /* Total cost of this path ignoring sorting costs */ 212 i8 isOrdered; /* No. of ORDER BY terms satisfied. -1 for unknown */ 213 WhereLoop **aLoop; /* Array of WhereLoop objects implementing this path */ 214 }; 215 216 /* 217 ** The query generator uses an array of instances of this structure to 218 ** help it analyze the subexpressions of the WHERE clause. Each WHERE 219 ** clause subexpression is separated from the others by AND operators, 220 ** usually, or sometimes subexpressions separated by OR. 221 ** 222 ** All WhereTerms are collected into a single WhereClause structure. 223 ** The following identity holds: 224 ** 225 ** WhereTerm.pWC->a[WhereTerm.idx] == WhereTerm 226 ** 227 ** When a term is of the form: 228 ** 229 ** X <op> <expr> 230 ** 231 ** where X is a column name and <op> is one of certain operators, 232 ** then WhereTerm.leftCursor and WhereTerm.u.leftColumn record the 233 ** cursor number and column number for X. WhereTerm.eOperator records 234 ** the <op> using a bitmask encoding defined by WO_xxx below. The 235 ** use of a bitmask encoding for the operator allows us to search 236 ** quickly for terms that match any of several different operators. 237 ** 238 ** A WhereTerm might also be two or more subterms connected by OR: 239 ** 240 ** (t1.X <op> <expr>) OR (t1.Y <op> <expr>) OR .... 241 ** 242 ** In this second case, wtFlag has the TERM_ORINFO bit set and eOperator==WO_OR 243 ** and the WhereTerm.u.pOrInfo field points to auxiliary information that 244 ** is collected about the OR clause. 245 ** 246 ** If a term in the WHERE clause does not match either of the two previous 247 ** categories, then eOperator==0. The WhereTerm.pExpr field is still set 248 ** to the original subexpression content and wtFlags is set up appropriately 249 ** but no other fields in the WhereTerm object are meaningful. 250 ** 251 ** When eOperator!=0, prereqRight and prereqAll record sets of cursor numbers, 252 ** but they do so indirectly. A single WhereMaskSet structure translates 253 ** cursor number into bits and the translated bit is stored in the prereq 254 ** fields. The translation is used in order to maximize the number of 255 ** bits that will fit in a Bitmask. The VDBE cursor numbers might be 256 ** spread out over the non-negative integers. For example, the cursor 257 ** numbers might be 3, 8, 9, 10, 20, 23, 41, and 45. The WhereMaskSet 258 ** translates these sparse cursor numbers into consecutive integers 259 ** beginning with 0 in order to make the best possible use of the available 260 ** bits in the Bitmask. So, in the example above, the cursor numbers 261 ** would be mapped into integers 0 through 7. 262 ** 263 ** The number of terms in a join is limited by the number of bits 264 ** in prereqRight and prereqAll. The default is 64 bits, hence SQLite 265 ** is only able to process joins with 64 or fewer tables. 266 */ 267 struct WhereTerm { 268 Expr *pExpr; /* Pointer to the subexpression that is this term */ 269 WhereClause *pWC; /* The clause this term is part of */ 270 LogEst truthProb; /* Probability of truth for this expression */ 271 u16 wtFlags; /* TERM_xxx bit flags. See below */ 272 u16 eOperator; /* A WO_xx value describing <op> */ 273 u8 nChild; /* Number of children that must disable us */ 274 u8 eMatchOp; /* Op for vtab MATCH/LIKE/GLOB/REGEXP terms */ 275 int iParent; /* Disable pWC->a[iParent] when this term disabled */ 276 int leftCursor; /* Cursor number of X in "X <op> <expr>" */ 277 union { 278 struct { 279 int leftColumn; /* Column number of X in "X <op> <expr>" */ 280 int iField; /* Field in (?,?,?) IN (SELECT...) vector */ 281 } x; /* Opcode other than OP_OR or OP_AND */ 282 WhereOrInfo *pOrInfo; /* Extra information if (eOperator & WO_OR)!=0 */ 283 WhereAndInfo *pAndInfo; /* Extra information if (eOperator& WO_AND)!=0 */ 284 } u; 285 Bitmask prereqRight; /* Bitmask of tables used by pExpr->pRight */ 286 Bitmask prereqAll; /* Bitmask of tables referenced by pExpr */ 287 }; 288 289 /* 290 ** Allowed values of WhereTerm.wtFlags 291 */ 292 #define TERM_DYNAMIC 0x0001 /* Need to call sqlite3ExprDelete(db, pExpr) */ 293 #define TERM_VIRTUAL 0x0002 /* Added by the optimizer. Do not code */ 294 #define TERM_CODED 0x0004 /* This term is already coded */ 295 #define TERM_COPIED 0x0008 /* Has a child */ 296 #define TERM_ORINFO 0x0010 /* Need to free the WhereTerm.u.pOrInfo object */ 297 #define TERM_ANDINFO 0x0020 /* Need to free the WhereTerm.u.pAndInfo obj */ 298 #define TERM_OK 0x0040 /* Used during OR-clause processing */ 299 #define TERM_VNULL 0x0080 /* Manufactured x>NULL or x<=NULL term */ 300 #define TERM_LIKEOPT 0x0100 /* Virtual terms from the LIKE optimization */ 301 #define TERM_LIKECOND 0x0200 /* Conditionally this LIKE operator term */ 302 #define TERM_LIKE 0x0400 /* The original LIKE operator */ 303 #define TERM_IS 0x0800 /* Term.pExpr is an IS operator */ 304 #define TERM_VARSELECT 0x1000 /* Term.pExpr contains a correlated sub-query */ 305 #define TERM_HEURTRUTH 0x2000 /* Heuristic truthProb used */ 306 #ifdef SQLITE_ENABLE_STAT4 307 # define TERM_HIGHTRUTH 0x4000 /* Term excludes few rows */ 308 #else 309 # define TERM_HIGHTRUTH 0 /* Only used with STAT4 */ 310 #endif 311 #define TERM_SLICE 0x8000 /* One slice of a row-value/vector comparison */ 312 313 /* 314 ** An instance of the WhereScan object is used as an iterator for locating 315 ** terms in the WHERE clause that are useful to the query planner. 316 */ 317 struct WhereScan { 318 WhereClause *pOrigWC; /* Original, innermost WhereClause */ 319 WhereClause *pWC; /* WhereClause currently being scanned */ 320 const char *zCollName; /* Required collating sequence, if not NULL */ 321 Expr *pIdxExpr; /* Search for this index expression */ 322 int k; /* Resume scanning at this->pWC->a[this->k] */ 323 u32 opMask; /* Acceptable operators */ 324 char idxaff; /* Must match this affinity, if zCollName!=NULL */ 325 unsigned char iEquiv; /* Current slot in aiCur[] and aiColumn[] */ 326 unsigned char nEquiv; /* Number of entries in aiCur[] and aiColumn[] */ 327 int aiCur[11]; /* Cursors in the equivalence class */ 328 i16 aiColumn[11]; /* Corresponding column number in the eq-class */ 329 }; 330 331 /* 332 ** An instance of the following structure holds all information about a 333 ** WHERE clause. Mostly this is a container for one or more WhereTerms. 334 ** 335 ** Explanation of pOuter: For a WHERE clause of the form 336 ** 337 ** a AND ((b AND c) OR (d AND e)) AND f 338 ** 339 ** There are separate WhereClause objects for the whole clause and for 340 ** the subclauses "(b AND c)" and "(d AND e)". The pOuter field of the 341 ** subclauses points to the WhereClause object for the whole clause. 342 */ 343 struct WhereClause { 344 WhereInfo *pWInfo; /* WHERE clause processing context */ 345 WhereClause *pOuter; /* Outer conjunction */ 346 u8 op; /* Split operator. TK_AND or TK_OR */ 347 u8 hasOr; /* True if any a[].eOperator is WO_OR */ 348 int nTerm; /* Number of terms */ 349 int nSlot; /* Number of entries in a[] */ 350 int nBase; /* Number of terms through the last non-Virtual */ 351 WhereTerm *a; /* Each a[] describes a term of the WHERE cluase */ 352 #if defined(SQLITE_SMALL_STACK) 353 WhereTerm aStatic[1]; /* Initial static space for a[] */ 354 #else 355 WhereTerm aStatic[8]; /* Initial static space for a[] */ 356 #endif 357 }; 358 359 /* 360 ** A WhereTerm with eOperator==WO_OR has its u.pOrInfo pointer set to 361 ** a dynamically allocated instance of the following structure. 362 */ 363 struct WhereOrInfo { 364 WhereClause wc; /* Decomposition into subterms */ 365 Bitmask indexable; /* Bitmask of all indexable tables in the clause */ 366 }; 367 368 /* 369 ** A WhereTerm with eOperator==WO_AND has its u.pAndInfo pointer set to 370 ** a dynamically allocated instance of the following structure. 371 */ 372 struct WhereAndInfo { 373 WhereClause wc; /* The subexpression broken out */ 374 }; 375 376 /* 377 ** An instance of the following structure keeps track of a mapping 378 ** between VDBE cursor numbers and bits of the bitmasks in WhereTerm. 379 ** 380 ** The VDBE cursor numbers are small integers contained in 381 ** SrcItem.iCursor and Expr.iTable fields. For any given WHERE 382 ** clause, the cursor numbers might not begin with 0 and they might 383 ** contain gaps in the numbering sequence. But we want to make maximum 384 ** use of the bits in our bitmasks. This structure provides a mapping 385 ** from the sparse cursor numbers into consecutive integers beginning 386 ** with 0. 387 ** 388 ** If WhereMaskSet.ix[A]==B it means that The A-th bit of a Bitmask 389 ** corresponds VDBE cursor number B. The A-th bit of a bitmask is 1<<A. 390 ** 391 ** For example, if the WHERE clause expression used these VDBE 392 ** cursors: 4, 5, 8, 29, 57, 73. Then the WhereMaskSet structure 393 ** would map those cursor numbers into bits 0 through 5. 394 ** 395 ** Note that the mapping is not necessarily ordered. In the example 396 ** above, the mapping might go like this: 4->3, 5->1, 8->2, 29->0, 397 ** 57->5, 73->4. Or one of 719 other combinations might be used. It 398 ** does not really matter. What is important is that sparse cursor 399 ** numbers all get mapped into bit numbers that begin with 0 and contain 400 ** no gaps. 401 */ 402 struct WhereMaskSet { 403 int bVarSelect; /* Used by sqlite3WhereExprUsage() */ 404 int n; /* Number of assigned cursor values */ 405 int ix[BMS]; /* Cursor assigned to each bit */ 406 }; 407 408 /* 409 ** This object is a convenience wrapper holding all information needed 410 ** to construct WhereLoop objects for a particular query. 411 */ 412 struct WhereLoopBuilder { 413 WhereInfo *pWInfo; /* Information about this WHERE */ 414 WhereClause *pWC; /* WHERE clause terms */ 415 WhereLoop *pNew; /* Template WhereLoop */ 416 WhereOrSet *pOrSet; /* Record best loops here, if not NULL */ 417 #ifdef SQLITE_ENABLE_STAT4 418 UnpackedRecord *pRec; /* Probe for stat4 (if required) */ 419 int nRecValid; /* Number of valid fields currently in pRec */ 420 #endif 421 unsigned char bldFlags1; /* First set of SQLITE_BLDF_* flags */ 422 unsigned char bldFlags2; /* Second set of SQLITE_BLDF_* flags */ 423 unsigned int iPlanLimit; /* Search limiter */ 424 }; 425 426 /* Allowed values for WhereLoopBuider.bldFlags */ 427 #define SQLITE_BLDF1_INDEXED 0x0001 /* An index is used */ 428 #define SQLITE_BLDF1_UNIQUE 0x0002 /* All keys of a UNIQUE index used */ 429 430 #define SQLITE_BLDF2_2NDPASS 0x0004 /* Second builder pass needed */ 431 432 /* The WhereLoopBuilder.iPlanLimit is used to limit the number of 433 ** index+constraint combinations the query planner will consider for a 434 ** particular query. If this parameter is unlimited, then certain 435 ** pathological queries can spend excess time in the sqlite3WhereBegin() 436 ** routine. The limit is high enough that is should not impact real-world 437 ** queries. 438 ** 439 ** SQLITE_QUERY_PLANNER_LIMIT is the baseline limit. The limit is 440 ** increased by SQLITE_QUERY_PLANNER_LIMIT_INCR before each term of the FROM 441 ** clause is processed, so that every table in a join is guaranteed to be 442 ** able to propose a some index+constraint combinations even if the initial 443 ** baseline limit was exhausted by prior tables of the join. 444 */ 445 #ifndef SQLITE_QUERY_PLANNER_LIMIT 446 # define SQLITE_QUERY_PLANNER_LIMIT 20000 447 #endif 448 #ifndef SQLITE_QUERY_PLANNER_LIMIT_INCR 449 # define SQLITE_QUERY_PLANNER_LIMIT_INCR 1000 450 #endif 451 452 /* 453 ** The WHERE clause processing routine has two halves. The 454 ** first part does the start of the WHERE loop and the second 455 ** half does the tail of the WHERE loop. An instance of 456 ** this structure is returned by the first half and passed 457 ** into the second half to give some continuity. 458 ** 459 ** An instance of this object holds the complete state of the query 460 ** planner. 461 */ 462 struct WhereInfo { 463 Parse *pParse; /* Parsing and code generating context */ 464 SrcList *pTabList; /* List of tables in the join */ 465 ExprList *pOrderBy; /* The ORDER BY clause or NULL */ 466 ExprList *pResultSet; /* Result set of the query */ 467 #if WHERETRACE_ENABLED 468 Expr *pWhere; /* The complete WHERE clause */ 469 #endif 470 #ifndef SQLITE_OMIT_VIRTUALTABLE 471 Select *pLimit; /* Used to access LIMIT expr/registers for vtabs */ 472 #endif 473 int aiCurOnePass[2]; /* OP_OpenWrite cursors for the ONEPASS opt */ 474 int iContinue; /* Jump here to continue with next record */ 475 int iBreak; /* Jump here to break out of the loop */ 476 int savedNQueryLoop; /* pParse->nQueryLoop outside the WHERE loop */ 477 u16 wctrlFlags; /* Flags originally passed to sqlite3WhereBegin() */ 478 LogEst iLimit; /* LIMIT if wctrlFlags has WHERE_USE_LIMIT */ 479 u8 nLevel; /* Number of nested loop */ 480 i8 nOBSat; /* Number of ORDER BY terms satisfied by indices */ 481 u8 eOnePass; /* ONEPASS_OFF, or _SINGLE, or _MULTI */ 482 u8 eDistinct; /* One of the WHERE_DISTINCT_* values */ 483 unsigned bDeferredSeek :1; /* Uses OP_DeferredSeek */ 484 unsigned untestedTerms :1; /* Not all WHERE terms resolved by outer loop */ 485 unsigned bOrderedInnerLoop:1;/* True if only the inner-most loop is ordered */ 486 unsigned sorted :1; /* True if really sorted (not just grouped) */ 487 LogEst nRowOut; /* Estimated number of output rows */ 488 int iTop; /* The very beginning of the WHERE loop */ 489 int iEndWhere; /* End of the WHERE clause itself */ 490 WhereLoop *pLoops; /* List of all WhereLoop objects */ 491 WhereMemBlock *pMemToFree;/* Memory to free when this object destroyed */ 492 Bitmask revMask; /* Mask of ORDER BY terms that need reversing */ 493 WhereClause sWC; /* Decomposition of the WHERE clause */ 494 WhereMaskSet sMaskSet; /* Map cursor numbers to bitmasks */ 495 WhereLevel a[1]; /* Information about each nest loop in WHERE */ 496 }; 497 498 /* 499 ** Private interfaces - callable only by other where.c routines. 500 ** 501 ** where.c: 502 */ 503 Bitmask sqlite3WhereGetMask(WhereMaskSet*,int); 504 #ifdef WHERETRACE_ENABLED 505 void sqlite3WhereClausePrint(WhereClause *pWC); 506 void sqlite3WhereTermPrint(WhereTerm *pTerm, int iTerm); 507 void sqlite3WhereLoopPrint(WhereLoop *p, WhereClause *pWC); 508 #endif 509 WhereTerm *sqlite3WhereFindTerm( 510 WhereClause *pWC, /* The WHERE clause to be searched */ 511 int iCur, /* Cursor number of LHS */ 512 int iColumn, /* Column number of LHS */ 513 Bitmask notReady, /* RHS must not overlap with this mask */ 514 u32 op, /* Mask of WO_xx values describing operator */ 515 Index *pIdx /* Must be compatible with this index, if not NULL */ 516 ); 517 void *sqlite3WhereMalloc(WhereInfo *pWInfo, u64 nByte); 518 void *sqlite3WhereRealloc(WhereInfo *pWInfo, void *pOld, u64 nByte); 519 520 /* wherecode.c: */ 521 #ifndef SQLITE_OMIT_EXPLAIN 522 int sqlite3WhereExplainOneScan( 523 Parse *pParse, /* Parse context */ 524 SrcList *pTabList, /* Table list this loop refers to */ 525 WhereLevel *pLevel, /* Scan to write OP_Explain opcode for */ 526 u16 wctrlFlags /* Flags passed to sqlite3WhereBegin() */ 527 ); 528 int sqlite3WhereExplainBloomFilter( 529 const Parse *pParse, /* Parse context */ 530 const WhereInfo *pWInfo, /* WHERE clause */ 531 const WhereLevel *pLevel /* Bloom filter on this level */ 532 ); 533 #else 534 # define sqlite3WhereExplainOneScan(u,v,w,x) 0 535 # define sqlite3WhereExplainBloomFilter(u,v,w) 0 536 #endif /* SQLITE_OMIT_EXPLAIN */ 537 #ifdef SQLITE_ENABLE_STMT_SCANSTATUS 538 void sqlite3WhereAddScanStatus( 539 Vdbe *v, /* Vdbe to add scanstatus entry to */ 540 SrcList *pSrclist, /* FROM clause pLvl reads data from */ 541 WhereLevel *pLvl, /* Level to add scanstatus() entry for */ 542 int addrExplain /* Address of OP_Explain (or 0) */ 543 ); 544 #else 545 # define sqlite3WhereAddScanStatus(a, b, c, d) ((void)d) 546 #endif 547 Bitmask sqlite3WhereCodeOneLoopStart( 548 Parse *pParse, /* Parsing context */ 549 Vdbe *v, /* Prepared statement under construction */ 550 WhereInfo *pWInfo, /* Complete information about the WHERE clause */ 551 int iLevel, /* Which level of pWInfo->a[] should be coded */ 552 WhereLevel *pLevel, /* The current level pointer */ 553 Bitmask notReady /* Which tables are currently available */ 554 ); 555 SQLITE_NOINLINE void sqlite3WhereRightJoinLoop( 556 WhereInfo *pWInfo, 557 int iLevel, 558 WhereLevel *pLevel 559 ); 560 561 /* whereexpr.c: */ 562 void sqlite3WhereClauseInit(WhereClause*,WhereInfo*); 563 void sqlite3WhereClauseClear(WhereClause*); 564 void sqlite3WhereSplit(WhereClause*,Expr*,u8); 565 void sqlite3WhereAddLimit(WhereClause*, Select*); 566 Bitmask sqlite3WhereExprUsage(WhereMaskSet*, Expr*); 567 Bitmask sqlite3WhereExprUsageNN(WhereMaskSet*, Expr*); 568 Bitmask sqlite3WhereExprListUsage(WhereMaskSet*, ExprList*); 569 void sqlite3WhereExprAnalyze(SrcList*, WhereClause*); 570 void sqlite3WhereTabFuncArgs(Parse*, SrcItem*, WhereClause*); 571 572 573 574 575 576 /* 577 ** Bitmasks for the operators on WhereTerm objects. These are all 578 ** operators that are of interest to the query planner. An 579 ** OR-ed combination of these values can be used when searching for 580 ** particular WhereTerms within a WhereClause. 581 ** 582 ** Value constraints: 583 ** WO_EQ == SQLITE_INDEX_CONSTRAINT_EQ 584 ** WO_LT == SQLITE_INDEX_CONSTRAINT_LT 585 ** WO_LE == SQLITE_INDEX_CONSTRAINT_LE 586 ** WO_GT == SQLITE_INDEX_CONSTRAINT_GT 587 ** WO_GE == SQLITE_INDEX_CONSTRAINT_GE 588 */ 589 #define WO_IN 0x0001 590 #define WO_EQ 0x0002 591 #define WO_LT (WO_EQ<<(TK_LT-TK_EQ)) 592 #define WO_LE (WO_EQ<<(TK_LE-TK_EQ)) 593 #define WO_GT (WO_EQ<<(TK_GT-TK_EQ)) 594 #define WO_GE (WO_EQ<<(TK_GE-TK_EQ)) 595 #define WO_AUX 0x0040 /* Op useful to virtual tables only */ 596 #define WO_IS 0x0080 597 #define WO_ISNULL 0x0100 598 #define WO_OR 0x0200 /* Two or more OR-connected terms */ 599 #define WO_AND 0x0400 /* Two or more AND-connected terms */ 600 #define WO_EQUIV 0x0800 /* Of the form A==B, both columns */ 601 #define WO_NOOP 0x1000 /* This term does not restrict search space */ 602 #define WO_ROWVAL 0x2000 /* A row-value term */ 603 604 #define WO_ALL 0x3fff /* Mask of all possible WO_* values */ 605 #define WO_SINGLE 0x01ff /* Mask of all non-compound WO_* values */ 606 607 /* 608 ** These are definitions of bits in the WhereLoop.wsFlags field. 609 ** The particular combination of bits in each WhereLoop help to 610 ** determine the algorithm that WhereLoop represents. 611 */ 612 #define WHERE_COLUMN_EQ 0x00000001 /* x=EXPR */ 613 #define WHERE_COLUMN_RANGE 0x00000002 /* x<EXPR and/or x>EXPR */ 614 #define WHERE_COLUMN_IN 0x00000004 /* x IN (...) */ 615 #define WHERE_COLUMN_NULL 0x00000008 /* x IS NULL */ 616 #define WHERE_CONSTRAINT 0x0000000f /* Any of the WHERE_COLUMN_xxx values */ 617 #define WHERE_TOP_LIMIT 0x00000010 /* x<EXPR or x<=EXPR constraint */ 618 #define WHERE_BTM_LIMIT 0x00000020 /* x>EXPR or x>=EXPR constraint */ 619 #define WHERE_BOTH_LIMIT 0x00000030 /* Both x>EXPR and x<EXPR */ 620 #define WHERE_IDX_ONLY 0x00000040 /* Use index only - omit table */ 621 #define WHERE_IPK 0x00000100 /* x is the INTEGER PRIMARY KEY */ 622 #define WHERE_INDEXED 0x00000200 /* WhereLoop.u.btree.pIndex is valid */ 623 #define WHERE_VIRTUALTABLE 0x00000400 /* WhereLoop.u.vtab is valid */ 624 #define WHERE_IN_ABLE 0x00000800 /* Able to support an IN operator */ 625 #define WHERE_ONEROW 0x00001000 /* Selects no more than one row */ 626 #define WHERE_MULTI_OR 0x00002000 /* OR using multiple indices */ 627 #define WHERE_AUTO_INDEX 0x00004000 /* Uses an ephemeral index */ 628 #define WHERE_SKIPSCAN 0x00008000 /* Uses the skip-scan algorithm */ 629 #define WHERE_UNQ_WANTED 0x00010000 /* WHERE_ONEROW would have been helpful*/ 630 #define WHERE_PARTIALIDX 0x00020000 /* The automatic index is partial */ 631 #define WHERE_IN_EARLYOUT 0x00040000 /* Perhaps quit IN loops early */ 632 #define WHERE_BIGNULL_SORT 0x00080000 /* Column nEq of index is BIGNULL */ 633 #define WHERE_IN_SEEKSCAN 0x00100000 /* Seek-scan optimization for IN */ 634 #define WHERE_TRANSCONS 0x00200000 /* Uses a transitive constraint */ 635 #define WHERE_BLOOMFILTER 0x00400000 /* Consider using a Bloom-filter */ 636 #define WHERE_SELFCULL 0x00800000 /* nOut reduced by extra WHERE terms */ 637 #define WHERE_OMIT_OFFSET 0x01000000 /* Set offset counter to zero */ 638 #define WHERE_VIEWSCAN 0x02000000 /* A full-scan of a VIEW or subquery */ 639 640 #endif /* !defined(SQLITE_WHEREINT_H) */ 641