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 37 /* 38 ** This object is a header on a block of allocated memory that will be 39 ** automatically freed when its WInfo oject is destructed. 40 */ 41 struct WhereMemBlock { 42 WhereMemBlock *pNext; /* Next block in the chain */ 43 u8 sz; /* Bytes of space */ 44 }; 45 46 /* 47 ** This object contains information needed to implement a single nested 48 ** loop in WHERE clause. 49 ** 50 ** Contrast this object with WhereLoop. This object describes the 51 ** implementation of the loop. WhereLoop describes the algorithm. 52 ** This object contains a pointer to the WhereLoop algorithm as one of 53 ** its elements. 54 ** 55 ** The WhereInfo object contains a single instance of this object for 56 ** each term in the FROM clause (which is to say, for each of the 57 ** nested loops as implemented). The order of WhereLevel objects determines 58 ** the loop nested order, with WhereInfo.a[0] being the outer loop and 59 ** WhereInfo.a[WhereInfo.nLevel-1] being the inner loop. 60 */ 61 struct WhereLevel { 62 int iLeftJoin; /* Memory cell used to implement LEFT OUTER JOIN */ 63 int iTabCur; /* The VDBE cursor used to access the table */ 64 int iIdxCur; /* The VDBE cursor used to access pIdx */ 65 int addrBrk; /* Jump here to break out of the loop */ 66 int addrNxt; /* Jump here to start the next IN combination */ 67 int addrSkip; /* Jump here for next iteration of skip-scan */ 68 int addrCont; /* Jump here to continue with the next loop cycle */ 69 int addrFirst; /* First instruction of interior of the loop */ 70 int addrBody; /* Beginning of the body of this loop */ 71 int regBignull; /* big-null flag reg. True if a NULL-scan is needed */ 72 int addrBignull; /* Jump here for next part of big-null scan */ 73 #ifndef SQLITE_LIKE_DOESNT_MATCH_BLOBS 74 u32 iLikeRepCntr; /* LIKE range processing counter register (times 2) */ 75 int addrLikeRep; /* LIKE range processing address */ 76 #endif 77 int regFilter; /* Bloom filter */ 78 int iRJMatch; /* Cursor or rowset used for matched RIGHT JOIN rows */ 79 u8 iFrom; /* Which entry in the FROM clause */ 80 u8 op, p3, p5; /* Opcode, P3 & P5 of the opcode that ends the loop */ 81 int p1, p2; /* Operands of the opcode used to end the loop */ 82 union { /* Information that depends on pWLoop->wsFlags */ 83 struct { 84 int nIn; /* Number of entries in aInLoop[] */ 85 struct InLoop { 86 int iCur; /* The VDBE cursor used by this IN operator */ 87 int addrInTop; /* Top of the IN loop */ 88 int iBase; /* Base register of multi-key index record */ 89 int nPrefix; /* Number of prior entires in the key */ 90 u8 eEndLoopOp; /* IN Loop terminator. OP_Next or OP_Prev */ 91 } *aInLoop; /* Information about each nested IN operator */ 92 } in; /* Used when pWLoop->wsFlags&WHERE_IN_ABLE */ 93 Index *pCoveringIdx; /* Possible covering index for WHERE_MULTI_OR */ 94 } u; 95 struct WhereLoop *pWLoop; /* The selected WhereLoop object */ 96 Bitmask notReady; /* FROM entries not usable at this level */ 97 #ifdef SQLITE_ENABLE_STMT_SCANSTATUS 98 int addrVisit; /* Address at which row is visited */ 99 #endif 100 }; 101 102 /* 103 ** Each instance of this object represents an algorithm for evaluating one 104 ** term of a join. Every term of the FROM clause will have at least 105 ** one corresponding WhereLoop object (unless INDEXED BY constraints 106 ** prevent a query solution - which is an error) and many terms of the 107 ** FROM clause will have multiple WhereLoop objects, each describing a 108 ** potential way of implementing that FROM-clause term, together with 109 ** dependencies and cost estimates for using the chosen algorithm. 110 ** 111 ** Query planning consists of building up a collection of these WhereLoop 112 ** objects, then computing a particular sequence of WhereLoop objects, with 113 ** one WhereLoop object per FROM clause term, that satisfy all dependencies 114 ** and that minimize the overall cost. 115 */ 116 struct WhereLoop { 117 Bitmask prereq; /* Bitmask of other loops that must run first */ 118 Bitmask maskSelf; /* Bitmask identifying table iTab */ 119 #ifdef SQLITE_DEBUG 120 char cId; /* Symbolic ID of this loop for debugging use */ 121 #endif 122 u8 iTab; /* Position in FROM clause of table for this loop */ 123 u8 iSortIdx; /* Sorting index number. 0==None */ 124 LogEst rSetup; /* One-time setup cost (ex: create transient index) */ 125 LogEst rRun; /* Cost of running each loop */ 126 LogEst nOut; /* Estimated number of output rows */ 127 union { 128 struct { /* Information for internal btree tables */ 129 u16 nEq; /* Number of equality constraints */ 130 u16 nBtm; /* Size of BTM vector */ 131 u16 nTop; /* Size of TOP vector */ 132 u16 nDistinctCol; /* Index columns used to sort for DISTINCT */ 133 Index *pIndex; /* Index used, or NULL */ 134 } btree; 135 struct { /* Information for virtual tables */ 136 int idxNum; /* Index number */ 137 u32 needFree : 1; /* True if sqlite3_free(idxStr) is needed */ 138 u32 bOmitOffset : 1; /* True to let virtual table handle offset */ 139 i8 isOrdered; /* True if satisfies ORDER BY */ 140 u16 omitMask; /* Terms that may be omitted */ 141 char *idxStr; /* Index identifier string */ 142 u32 mHandleIn; /* Terms to handle as IN(...) instead of == */ 143 } vtab; 144 } u; 145 u32 wsFlags; /* WHERE_* flags describing the plan */ 146 u16 nLTerm; /* Number of entries in aLTerm[] */ 147 u16 nSkip; /* Number of NULL aLTerm[] entries */ 148 /**** whereLoopXfer() copies fields above ***********************/ 149 # define WHERE_LOOP_XFER_SZ offsetof(WhereLoop,nLSlot) 150 u16 nLSlot; /* Number of slots allocated for aLTerm[] */ 151 WhereTerm **aLTerm; /* WhereTerms used */ 152 WhereLoop *pNextLoop; /* Next WhereLoop object in the WhereClause */ 153 WhereTerm *aLTermSpace[3]; /* Initial aLTerm[] space */ 154 }; 155 156 /* This object holds the prerequisites and the cost of running a 157 ** subquery on one operand of an OR operator in the WHERE clause. 158 ** See WhereOrSet for additional information 159 */ 160 struct WhereOrCost { 161 Bitmask prereq; /* Prerequisites */ 162 LogEst rRun; /* Cost of running this subquery */ 163 LogEst nOut; /* Number of outputs for this subquery */ 164 }; 165 166 /* The WhereOrSet object holds a set of possible WhereOrCosts that 167 ** correspond to the subquery(s) of OR-clause processing. Only the 168 ** best N_OR_COST elements are retained. 169 */ 170 #define N_OR_COST 3 171 struct WhereOrSet { 172 u16 n; /* Number of valid a[] entries */ 173 WhereOrCost a[N_OR_COST]; /* Set of best costs */ 174 }; 175 176 /* 177 ** Each instance of this object holds a sequence of WhereLoop objects 178 ** that implement some or all of a query plan. 179 ** 180 ** Think of each WhereLoop object as a node in a graph with arcs 181 ** showing dependencies and costs for travelling between nodes. (That is 182 ** not a completely accurate description because WhereLoop costs are a 183 ** vector, not a scalar, and because dependencies are many-to-one, not 184 ** one-to-one as are graph nodes. But it is a useful visualization aid.) 185 ** Then a WherePath object is a path through the graph that visits some 186 ** or all of the WhereLoop objects once. 187 ** 188 ** The "solver" works by creating the N best WherePath objects of length 189 ** 1. Then using those as a basis to compute the N best WherePath objects 190 ** of length 2. And so forth until the length of WherePaths equals the 191 ** number of nodes in the FROM clause. The best (lowest cost) WherePath 192 ** at the end is the chosen query plan. 193 */ 194 struct WherePath { 195 Bitmask maskLoop; /* Bitmask of all WhereLoop objects in this path */ 196 Bitmask revLoop; /* aLoop[]s that should be reversed for ORDER BY */ 197 LogEst nRow; /* Estimated number of rows generated by this path */ 198 LogEst rCost; /* Total cost of this path */ 199 LogEst rUnsorted; /* Total cost of this path ignoring sorting costs */ 200 i8 isOrdered; /* No. of ORDER BY terms satisfied. -1 for unknown */ 201 WhereLoop **aLoop; /* Array of WhereLoop objects implementing this path */ 202 }; 203 204 /* 205 ** The query generator uses an array of instances of this structure to 206 ** help it analyze the subexpressions of the WHERE clause. Each WHERE 207 ** clause subexpression is separated from the others by AND operators, 208 ** usually, or sometimes subexpressions separated by OR. 209 ** 210 ** All WhereTerms are collected into a single WhereClause structure. 211 ** The following identity holds: 212 ** 213 ** WhereTerm.pWC->a[WhereTerm.idx] == WhereTerm 214 ** 215 ** When a term is of the form: 216 ** 217 ** X <op> <expr> 218 ** 219 ** where X is a column name and <op> is one of certain operators, 220 ** then WhereTerm.leftCursor and WhereTerm.u.leftColumn record the 221 ** cursor number and column number for X. WhereTerm.eOperator records 222 ** the <op> using a bitmask encoding defined by WO_xxx below. The 223 ** use of a bitmask encoding for the operator allows us to search 224 ** quickly for terms that match any of several different operators. 225 ** 226 ** A WhereTerm might also be two or more subterms connected by OR: 227 ** 228 ** (t1.X <op> <expr>) OR (t1.Y <op> <expr>) OR .... 229 ** 230 ** In this second case, wtFlag has the TERM_ORINFO bit set and eOperator==WO_OR 231 ** and the WhereTerm.u.pOrInfo field points to auxiliary information that 232 ** is collected about the OR clause. 233 ** 234 ** If a term in the WHERE clause does not match either of the two previous 235 ** categories, then eOperator==0. The WhereTerm.pExpr field is still set 236 ** to the original subexpression content and wtFlags is set up appropriately 237 ** but no other fields in the WhereTerm object are meaningful. 238 ** 239 ** When eOperator!=0, prereqRight and prereqAll record sets of cursor numbers, 240 ** but they do so indirectly. A single WhereMaskSet structure translates 241 ** cursor number into bits and the translated bit is stored in the prereq 242 ** fields. The translation is used in order to maximize the number of 243 ** bits that will fit in a Bitmask. The VDBE cursor numbers might be 244 ** spread out over the non-negative integers. For example, the cursor 245 ** numbers might be 3, 8, 9, 10, 20, 23, 41, and 45. The WhereMaskSet 246 ** translates these sparse cursor numbers into consecutive integers 247 ** beginning with 0 in order to make the best possible use of the available 248 ** bits in the Bitmask. So, in the example above, the cursor numbers 249 ** would be mapped into integers 0 through 7. 250 ** 251 ** The number of terms in a join is limited by the number of bits 252 ** in prereqRight and prereqAll. The default is 64 bits, hence SQLite 253 ** is only able to process joins with 64 or fewer tables. 254 */ 255 struct WhereTerm { 256 Expr *pExpr; /* Pointer to the subexpression that is this term */ 257 WhereClause *pWC; /* The clause this term is part of */ 258 LogEst truthProb; /* Probability of truth for this expression */ 259 u16 wtFlags; /* TERM_xxx bit flags. See below */ 260 u16 eOperator; /* A WO_xx value describing <op> */ 261 u8 nChild; /* Number of children that must disable us */ 262 u8 eMatchOp; /* Op for vtab MATCH/LIKE/GLOB/REGEXP terms */ 263 int iParent; /* Disable pWC->a[iParent] when this term disabled */ 264 int leftCursor; /* Cursor number of X in "X <op> <expr>" */ 265 union { 266 struct { 267 int leftColumn; /* Column number of X in "X <op> <expr>" */ 268 int iField; /* Field in (?,?,?) IN (SELECT...) vector */ 269 } x; /* Opcode other than OP_OR or OP_AND */ 270 WhereOrInfo *pOrInfo; /* Extra information if (eOperator & WO_OR)!=0 */ 271 WhereAndInfo *pAndInfo; /* Extra information if (eOperator& WO_AND)!=0 */ 272 } u; 273 Bitmask prereqRight; /* Bitmask of tables used by pExpr->pRight */ 274 Bitmask prereqAll; /* Bitmask of tables referenced by pExpr */ 275 }; 276 277 /* 278 ** Allowed values of WhereTerm.wtFlags 279 */ 280 #define TERM_DYNAMIC 0x0001 /* Need to call sqlite3ExprDelete(db, pExpr) */ 281 #define TERM_VIRTUAL 0x0002 /* Added by the optimizer. Do not code */ 282 #define TERM_CODED 0x0004 /* This term is already coded */ 283 #define TERM_COPIED 0x0008 /* Has a child */ 284 #define TERM_ORINFO 0x0010 /* Need to free the WhereTerm.u.pOrInfo object */ 285 #define TERM_ANDINFO 0x0020 /* Need to free the WhereTerm.u.pAndInfo obj */ 286 #define TERM_OK 0x0040 /* Used during OR-clause processing */ 287 #define TERM_VNULL 0x0080 /* Manufactured x>NULL or x<=NULL term */ 288 #define TERM_LIKEOPT 0x0100 /* Virtual terms from the LIKE optimization */ 289 #define TERM_LIKECOND 0x0200 /* Conditionally this LIKE operator term */ 290 #define TERM_LIKE 0x0400 /* The original LIKE operator */ 291 #define TERM_IS 0x0800 /* Term.pExpr is an IS operator */ 292 #define TERM_VARSELECT 0x1000 /* Term.pExpr contains a correlated sub-query */ 293 #define TERM_HEURTRUTH 0x2000 /* Heuristic truthProb used */ 294 #ifdef SQLITE_ENABLE_STAT4 295 # define TERM_HIGHTRUTH 0x4000 /* Term excludes few rows */ 296 #else 297 # define TERM_HIGHTRUTH 0 /* Only used with STAT4 */ 298 #endif 299 #define TERM_SLICE 0x8000 /* One slice of a row-value/vector comparison */ 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 int k; /* Resume scanning at this->pWC->a[this->k] */ 311 u32 opMask; /* Acceptable operators */ 312 char idxaff; /* Must match this affinity, if zCollName!=NULL */ 313 unsigned char iEquiv; /* Current slot in aiCur[] and aiColumn[] */ 314 unsigned char nEquiv; /* Number of entries in aiCur[] and aiColumn[] */ 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 int nBase; /* Number of terms through the last non-Virtual */ 339 WhereTerm *a; /* Each a[] describes a term of the WHERE cluase */ 340 #if defined(SQLITE_SMALL_STACK) 341 WhereTerm aStatic[1]; /* Initial static space for a[] */ 342 #else 343 WhereTerm aStatic[8]; /* Initial static space for a[] */ 344 #endif 345 }; 346 347 /* 348 ** A WhereTerm with eOperator==WO_OR has its u.pOrInfo pointer set to 349 ** a dynamically allocated instance of the following structure. 350 */ 351 struct WhereOrInfo { 352 WhereClause wc; /* Decomposition into subterms */ 353 Bitmask indexable; /* Bitmask of all indexable tables in the clause */ 354 }; 355 356 /* 357 ** A WhereTerm with eOperator==WO_AND has its u.pAndInfo pointer set to 358 ** a dynamically allocated instance of the following structure. 359 */ 360 struct WhereAndInfo { 361 WhereClause wc; /* The subexpression broken out */ 362 }; 363 364 /* 365 ** An instance of the following structure keeps track of a mapping 366 ** between VDBE cursor numbers and bits of the bitmasks in WhereTerm. 367 ** 368 ** The VDBE cursor numbers are small integers contained in 369 ** SrcList_item.iCursor and Expr.iTable fields. For any given WHERE 370 ** clause, the cursor numbers might not begin with 0 and they might 371 ** contain gaps in the numbering sequence. But we want to make maximum 372 ** use of the bits in our bitmasks. This structure provides a mapping 373 ** from the sparse cursor numbers into consecutive integers beginning 374 ** with 0. 375 ** 376 ** If WhereMaskSet.ix[A]==B it means that The A-th bit of a Bitmask 377 ** corresponds VDBE cursor number B. The A-th bit of a bitmask is 1<<A. 378 ** 379 ** For example, if the WHERE clause expression used these VDBE 380 ** cursors: 4, 5, 8, 29, 57, 73. Then the WhereMaskSet structure 381 ** would map those cursor numbers into bits 0 through 5. 382 ** 383 ** Note that the mapping is not necessarily ordered. In the example 384 ** above, the mapping might go like this: 4->3, 5->1, 8->2, 29->0, 385 ** 57->5, 73->4. Or one of 719 other combinations might be used. It 386 ** does not really matter. What is important is that sparse cursor 387 ** numbers all get mapped into bit numbers that begin with 0 and contain 388 ** no gaps. 389 */ 390 struct WhereMaskSet { 391 int bVarSelect; /* Used by sqlite3WhereExprUsage() */ 392 int n; /* Number of assigned cursor values */ 393 int ix[BMS]; /* Cursor assigned to each bit */ 394 }; 395 396 /* 397 ** This object is a convenience wrapper holding all information needed 398 ** to construct WhereLoop objects for a particular query. 399 */ 400 struct WhereLoopBuilder { 401 WhereInfo *pWInfo; /* Information about this WHERE */ 402 WhereClause *pWC; /* WHERE clause terms */ 403 WhereLoop *pNew; /* Template WhereLoop */ 404 WhereOrSet *pOrSet; /* Record best loops here, if not NULL */ 405 #ifdef SQLITE_ENABLE_STAT4 406 UnpackedRecord *pRec; /* Probe for stat4 (if required) */ 407 int nRecValid; /* Number of valid fields currently in pRec */ 408 #endif 409 unsigned char bldFlags1; /* First set of SQLITE_BLDF_* flags */ 410 unsigned char bldFlags2; /* Second set of SQLITE_BLDF_* flags */ 411 unsigned int iPlanLimit; /* Search limiter */ 412 }; 413 414 /* Allowed values for WhereLoopBuider.bldFlags */ 415 #define SQLITE_BLDF1_INDEXED 0x0001 /* An index is used */ 416 #define SQLITE_BLDF1_UNIQUE 0x0002 /* All keys of a UNIQUE index used */ 417 418 #define SQLITE_BLDF2_2NDPASS 0x0004 /* Second builder pass needed */ 419 420 /* The WhereLoopBuilder.iPlanLimit is used to limit the number of 421 ** index+constraint combinations the query planner will consider for a 422 ** particular query. If this parameter is unlimited, then certain 423 ** pathological queries can spend excess time in the sqlite3WhereBegin() 424 ** routine. The limit is high enough that is should not impact real-world 425 ** queries. 426 ** 427 ** SQLITE_QUERY_PLANNER_LIMIT is the baseline limit. The limit is 428 ** increased by SQLITE_QUERY_PLANNER_LIMIT_INCR before each term of the FROM 429 ** clause is processed, so that every table in a join is guaranteed to be 430 ** able to propose a some index+constraint combinations even if the initial 431 ** baseline limit was exhausted by prior tables of the join. 432 */ 433 #ifndef SQLITE_QUERY_PLANNER_LIMIT 434 # define SQLITE_QUERY_PLANNER_LIMIT 20000 435 #endif 436 #ifndef SQLITE_QUERY_PLANNER_LIMIT_INCR 437 # define SQLITE_QUERY_PLANNER_LIMIT_INCR 1000 438 #endif 439 440 /* 441 ** Each instance of this object records a change to a single node 442 ** in an expression tree to cause that node to point to a column 443 ** of an index rather than an expression or a virtual column. All 444 ** such transformations need to be undone at the end of WHERE clause 445 ** processing. 446 */ 447 typedef struct WhereExprMod WhereExprMod; 448 struct WhereExprMod { 449 WhereExprMod *pNext; /* Next translation on a list of them all */ 450 Expr *pExpr; /* The Expr node that was transformed */ 451 Expr orig; /* Original value of the Expr node */ 452 }; 453 454 /* 455 ** The WHERE clause processing routine has two halves. The 456 ** first part does the start of the WHERE loop and the second 457 ** half does the tail of the WHERE loop. An instance of 458 ** this structure is returned by the first half and passed 459 ** into the second half to give some continuity. 460 ** 461 ** An instance of this object holds the complete state of the query 462 ** planner. 463 */ 464 struct WhereInfo { 465 Parse *pParse; /* Parsing and code generating context */ 466 SrcList *pTabList; /* List of tables in the join */ 467 ExprList *pOrderBy; /* The ORDER BY clause or NULL */ 468 ExprList *pResultSet; /* Result set of the query */ 469 Expr *pWhere; /* The complete WHERE clause */ 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 WhereExprMod *pExprMods; /* Expression modifications */ 492 WhereMemBlock *pMemToFree;/* Memory to free when this object destroyed */ 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 void *sqlite3WhereMalloc(WhereInfo *pWInfo, u64 nByte); 519 void *sqlite3WhereRealloc(WhereInfo *pWInfo, void *pOld, u64 nByte); 520 521 /* wherecode.c: */ 522 #ifndef SQLITE_OMIT_EXPLAIN 523 int sqlite3WhereExplainOneScan( 524 Parse *pParse, /* Parse context */ 525 SrcList *pTabList, /* Table list this loop refers to */ 526 WhereLevel *pLevel, /* Scan to write OP_Explain opcode for */ 527 u16 wctrlFlags /* Flags passed to sqlite3WhereBegin() */ 528 ); 529 int sqlite3WhereExplainBloomFilter( 530 const Parse *pParse, /* Parse context */ 531 const WhereInfo *pWInfo, /* WHERE clause */ 532 const WhereLevel *pLevel /* Bloom filter on this level */ 533 ); 534 #else 535 # define sqlite3WhereExplainOneScan(u,v,w,x) 0 536 # define sqlite3WhereExplainBloomFilter(u,v,w) 0 537 #endif /* SQLITE_OMIT_EXPLAIN */ 538 #ifdef SQLITE_ENABLE_STMT_SCANSTATUS 539 void sqlite3WhereAddScanStatus( 540 Vdbe *v, /* Vdbe to add scanstatus entry to */ 541 SrcList *pSrclist, /* FROM clause pLvl reads data from */ 542 WhereLevel *pLvl, /* Level to add scanstatus() entry for */ 543 int addrExplain /* Address of OP_Explain (or 0) */ 544 ); 545 #else 546 # define sqlite3WhereAddScanStatus(a, b, c, d) ((void)d) 547 #endif 548 Bitmask sqlite3WhereCodeOneLoopStart( 549 Parse *pParse, /* Parsing context */ 550 Vdbe *v, /* Prepared statement under construction */ 551 WhereInfo *pWInfo, /* Complete information about the WHERE clause */ 552 int iLevel, /* Which level of pWInfo->a[] should be coded */ 553 WhereLevel *pLevel, /* The current level pointer */ 554 Bitmask notReady /* Which tables are currently available */ 555 ); 556 557 /* whereexpr.c: */ 558 void sqlite3WhereClauseInit(WhereClause*,WhereInfo*); 559 void sqlite3WhereClauseClear(WhereClause*); 560 void sqlite3WhereSplit(WhereClause*,Expr*,u8); 561 void sqlite3WhereAddLimit(WhereClause*, Select*); 562 Bitmask sqlite3WhereExprUsage(WhereMaskSet*, Expr*); 563 Bitmask sqlite3WhereExprUsageNN(WhereMaskSet*, Expr*); 564 Bitmask sqlite3WhereExprListUsage(WhereMaskSet*, ExprList*); 565 void sqlite3WhereExprAnalyze(SrcList*, WhereClause*); 566 void sqlite3WhereTabFuncArgs(Parse*, SrcItem*, WhereClause*); 567 568 569 570 571 572 /* 573 ** Bitmasks for the operators on WhereTerm objects. These are all 574 ** operators that are of interest to the query planner. An 575 ** OR-ed combination of these values can be used when searching for 576 ** particular WhereTerms within a WhereClause. 577 ** 578 ** Value constraints: 579 ** WO_EQ == SQLITE_INDEX_CONSTRAINT_EQ 580 ** WO_LT == SQLITE_INDEX_CONSTRAINT_LT 581 ** WO_LE == SQLITE_INDEX_CONSTRAINT_LE 582 ** WO_GT == SQLITE_INDEX_CONSTRAINT_GT 583 ** WO_GE == SQLITE_INDEX_CONSTRAINT_GE 584 */ 585 #define WO_IN 0x0001 586 #define WO_EQ 0x0002 587 #define WO_LT (WO_EQ<<(TK_LT-TK_EQ)) 588 #define WO_LE (WO_EQ<<(TK_LE-TK_EQ)) 589 #define WO_GT (WO_EQ<<(TK_GT-TK_EQ)) 590 #define WO_GE (WO_EQ<<(TK_GE-TK_EQ)) 591 #define WO_AUX 0x0040 /* Op useful to virtual tables only */ 592 #define WO_IS 0x0080 593 #define WO_ISNULL 0x0100 594 #define WO_OR 0x0200 /* Two or more OR-connected terms */ 595 #define WO_AND 0x0400 /* Two or more AND-connected terms */ 596 #define WO_EQUIV 0x0800 /* Of the form A==B, both columns */ 597 #define WO_NOOP 0x1000 /* This term does not restrict search space */ 598 599 #define WO_ALL 0x1fff /* Mask of all possible WO_* values */ 600 #define WO_SINGLE 0x01ff /* Mask of all non-compound WO_* values */ 601 602 /* 603 ** These are definitions of bits in the WhereLoop.wsFlags field. 604 ** The particular combination of bits in each WhereLoop help to 605 ** determine the algorithm that WhereLoop represents. 606 */ 607 #define WHERE_COLUMN_EQ 0x00000001 /* x=EXPR */ 608 #define WHERE_COLUMN_RANGE 0x00000002 /* x<EXPR and/or x>EXPR */ 609 #define WHERE_COLUMN_IN 0x00000004 /* x IN (...) */ 610 #define WHERE_COLUMN_NULL 0x00000008 /* x IS NULL */ 611 #define WHERE_CONSTRAINT 0x0000000f /* Any of the WHERE_COLUMN_xxx values */ 612 #define WHERE_TOP_LIMIT 0x00000010 /* x<EXPR or x<=EXPR constraint */ 613 #define WHERE_BTM_LIMIT 0x00000020 /* x>EXPR or x>=EXPR constraint */ 614 #define WHERE_BOTH_LIMIT 0x00000030 /* Both x>EXPR and x<EXPR */ 615 #define WHERE_IDX_ONLY 0x00000040 /* Use index only - omit table */ 616 #define WHERE_IPK 0x00000100 /* x is the INTEGER PRIMARY KEY */ 617 #define WHERE_INDEXED 0x00000200 /* WhereLoop.u.btree.pIndex is valid */ 618 #define WHERE_VIRTUALTABLE 0x00000400 /* WhereLoop.u.vtab is valid */ 619 #define WHERE_IN_ABLE 0x00000800 /* Able to support an IN operator */ 620 #define WHERE_ONEROW 0x00001000 /* Selects no more than one row */ 621 #define WHERE_MULTI_OR 0x00002000 /* OR using multiple indices */ 622 #define WHERE_AUTO_INDEX 0x00004000 /* Uses an ephemeral index */ 623 #define WHERE_SKIPSCAN 0x00008000 /* Uses the skip-scan algorithm */ 624 #define WHERE_UNQ_WANTED 0x00010000 /* WHERE_ONEROW would have been helpful*/ 625 #define WHERE_PARTIALIDX 0x00020000 /* The automatic index is partial */ 626 #define WHERE_IN_EARLYOUT 0x00040000 /* Perhaps quit IN loops early */ 627 #define WHERE_BIGNULL_SORT 0x00080000 /* Column nEq of index is BIGNULL */ 628 #define WHERE_IN_SEEKSCAN 0x00100000 /* Seek-scan optimization for IN */ 629 #define WHERE_TRANSCONS 0x00200000 /* Uses a transitive constraint */ 630 #define WHERE_BLOOMFILTER 0x00400000 /* Consider using a Bloom-filter */ 631 #define WHERE_SELFCULL 0x00800000 /* nOut reduced by extra WHERE terms */ 632 #define WHERE_OMIT_OFFSET 0x01000000 /* Set offset counter to zero */ 633 634 #endif /* !defined(SQLITE_WHEREINT_H) */ 635