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| 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 | |
| 18 /* | |
| 19 ** Trace output macros | |
| 20 */ | |
| 21 #if defined(SQLITE_TEST) || defined(SQLITE_DEBUG) | |
| 22 /***/ int sqlite3WhereTrace = 0; | |
| 23 #endif | |
| 24 #if defined(SQLITE_DEBUG) \ | |
| 25 && (defined(SQLITE_TEST) || defined(SQLITE_ENABLE_WHERETRACE)) | |
| 26 # define WHERETRACE(K,X) if(sqlite3WhereTrace&(K)) sqlite3DebugPrintf X | |
| 27 # define WHERETRACE_ENABLED 1 | |
| 28 #else | |
| 29 # define WHERETRACE(K,X) | |
| 30 #endif | |
| 31 | |
| 32 /* Forward references | |
| 33 */ | |
| 34 typedef struct WhereClause WhereClause; | |
| 35 typedef struct WhereMaskSet WhereMaskSet; | |
| 36 typedef struct WhereOrInfo WhereOrInfo; | |
| 37 typedef struct WhereAndInfo WhereAndInfo; | |
| 38 typedef struct WhereLevel WhereLevel; | |
| 39 typedef struct WhereLoop WhereLoop; | |
| 40 typedef struct WherePath WherePath; | |
| 41 typedef struct WhereTerm WhereTerm; | |
| 42 typedef struct WhereLoopBuilder WhereLoopBuilder; | |
| 43 typedef struct WhereScan WhereScan; | |
| 44 typedef struct WhereOrCost WhereOrCost; | |
| 45 typedef struct WhereOrSet WhereOrSet; | |
| 46 | |
| 47 /* | |
| 48 ** This object contains information needed to implement a single nested | |
| 49 ** loop in WHERE clause. | |
| 50 ** | |
| 51 ** Contrast this object with WhereLoop. This object describes the | |
| 52 ** implementation of the loop. WhereLoop describes the algorithm. | |
| 53 ** This object contains a pointer to the WhereLoop algorithm as one of | |
| 54 ** its elements. | |
| 55 ** | |
| 56 ** The WhereInfo object contains a single instance of this object for | |
| 57 ** each term in the FROM clause (which is to say, for each of the | |
| 58 ** nested loops as implemented). The order of WhereLevel objects determines | |
| 59 ** the loop nested order, with WhereInfo.a[0] being the outer loop and | |
| 60 ** WhereInfo.a[WhereInfo.nLevel-1] being the inner loop. | |
| 61 */ | |
| 62 struct WhereLevel { | |
| 63 int iLeftJoin; /* Memory cell used to implement LEFT OUTER JOIN */ | |
| 64 int iTabCur; /* The VDBE cursor used to access the table */ | |
| 65 int iIdxCur; /* The VDBE cursor used to access pIdx */ | |
| 66 int addrBrk; /* Jump here to break out of the loop */ | |
| 67 int addrNxt; /* Jump here to start the next IN combination */ | |
| 68 int addrSkip; /* Jump here for next iteration of skip-scan */ | |
| 69 int addrCont; /* Jump here to continue with the next loop cycle */ | |
| 70 int addrFirst; /* First instruction of interior of the loop */ | |
| 71 int addrBody; /* Beginning of the body of this loop */ | |
| 72 u8 iFrom; /* Which entry in the FROM clause */ | |
| 73 u8 op, p3, p5; /* Opcode, P3 & P5 of the opcode that ends the loop */ | |
| 74 int p1, p2; /* Operands of the opcode used to ends the loop */ | |
| 75 union { /* Information that depends on pWLoop->wsFlags */ | |
| 76 struct { | |
| 77 int nIn; /* Number of entries in aInLoop[] */ | |
| 78 struct InLoop { | |
| 79 int iCur; /* The VDBE cursor used by this IN operator */ | |
| 80 int addrInTop; /* Top of the IN loop */ | |
| 81 u8 eEndLoopOp; /* IN Loop terminator. OP_Next or OP_Prev */ | |
| 82 } *aInLoop; /* Information about each nested IN operator */ | |
| 83 } in; /* Used when pWLoop->wsFlags&WHERE_IN_ABLE */ | |
| 84 Index *pCovidx; /* Possible covering index for WHERE_MULTI_OR */ | |
| 85 } u; | |
| 86 struct WhereLoop *pWLoop; /* The selected WhereLoop object */ | |
| 87 Bitmask notReady; /* FROM entries not usable at this level */ | |
| 88 }; | |
| 89 | |
| 90 /* | |
| 91 ** Each instance of this object represents an algorithm for evaluating one | |
| 92 ** term of a join. Every term of the FROM clause will have at least | |
| 93 ** one corresponding WhereLoop object (unless INDEXED BY constraints | |
| 94 ** prevent a query solution - which is an error) and many terms of the | |
| 95 ** FROM clause will have multiple WhereLoop objects, each describing a | |
| 96 ** potential way of implementing that FROM-clause term, together with | |
| 97 ** dependencies and cost estimates for using the chosen algorithm. | |
| 98 ** | |
| 99 ** Query planning consists of building up a collection of these WhereLoop | |
| 100 ** objects, then computing a particular sequence of WhereLoop objects, with | |
| 101 ** one WhereLoop object per FROM clause term, that satisfy all dependencies | |
| 102 ** and that minimize the overall cost. | |
| 103 */ | |
| 104 struct WhereLoop { | |
| 105 Bitmask prereq; /* Bitmask of other loops that must run first */ | |
| 106 Bitmask maskSelf; /* Bitmask identifying table iTab */ | |
| 107 #ifdef SQLITE_DEBUG | |
| 108 char cId; /* Symbolic ID of this loop for debugging use */ | |
| 109 #endif | |
| 110 u8 iTab; /* Position in FROM clause of table for this loop */ | |
| 111 u8 iSortIdx; /* Sorting index number. 0==None */ | |
| 112 LogEst rSetup; /* One-time setup cost (ex: create transient index) */ | |
| 113 LogEst rRun; /* Cost of running each loop */ | |
| 114 LogEst nOut; /* Estimated number of output rows */ | |
| 115 union { | |
| 116 struct { /* Information for internal btree tables */ | |
| 117 u16 nEq; /* Number of equality constraints */ | |
| 118 u16 nSkip; /* Number of initial index columns to skip */ | |
| 119 Index *pIndex; /* Index used, or NULL */ | |
| 120 } btree; | |
| 121 struct { /* Information for virtual tables */ | |
| 122 int idxNum; /* Index number */ | |
| 123 u8 needFree; /* True if sqlite3_free(idxStr) is needed */ | |
| 124 i8 isOrdered; /* True if satisfies ORDER BY */ | |
| 125 u16 omitMask; /* Terms that may be omitted */ | |
| 126 char *idxStr; /* Index identifier string */ | |
| 127 } vtab; | |
| 128 } u; | |
| 129 u32 wsFlags; /* WHERE_* flags describing the plan */ | |
| 130 u16 nLTerm; /* Number of entries in aLTerm[] */ | |
| 131 /**** whereLoopXfer() copies fields above ***********************/ | |
| 132 # define WHERE_LOOP_XFER_SZ offsetof(WhereLoop,nLSlot) | |
| 133 u16 nLSlot; /* Number of slots allocated for aLTerm[] */ | |
| 134 WhereTerm **aLTerm; /* WhereTerms used */ | |
| 135 WhereLoop *pNextLoop; /* Next WhereLoop object in the WhereClause */ | |
| 136 WhereTerm *aLTermSpace[4]; /* Initial aLTerm[] space */ | |
| 137 }; | |
| 138 | |
| 139 /* This object holds the prerequisites and the cost of running a | |
| 140 ** subquery on one operand of an OR operator in the WHERE clause. | |
| 141 ** See WhereOrSet for additional information | |
| 142 */ | |
| 143 struct WhereOrCost { | |
| 144 Bitmask prereq; /* Prerequisites */ | |
| 145 LogEst rRun; /* Cost of running this subquery */ | |
| 146 LogEst nOut; /* Number of outputs for this subquery */ | |
| 147 }; | |
| 148 | |
| 149 /* The WhereOrSet object holds a set of possible WhereOrCosts that | |
| 150 ** correspond to the subquery(s) of OR-clause processing. Only the | |
| 151 ** best N_OR_COST elements are retained. | |
| 152 */ | |
| 153 #define N_OR_COST 3 | |
| 154 struct WhereOrSet { | |
| 155 u16 n; /* Number of valid a[] entries */ | |
| 156 WhereOrCost a[N_OR_COST]; /* Set of best costs */ | |
| 157 }; | |
| 158 | |
| 159 | |
| 160 /* Forward declaration of methods */ | |
| 161 static int whereLoopResize(sqlite3*, WhereLoop*, int); | |
| 162 | |
| 163 /* | |
| 164 ** Each instance of this object holds a sequence of WhereLoop objects | |
| 165 ** that implement some or all of a query plan. | |
| 166 ** | |
| 167 ** Think of each WhereLoop object as a node in a graph with arcs | |
| 168 ** showing dependencies and costs for travelling between nodes. (That is | |
| 169 ** not a completely accurate description because WhereLoop costs are a | |
| 170 ** vector, not a scalar, and because dependencies are many-to-one, not | |
| 171 ** one-to-one as are graph nodes. But it is a useful visualization aid.) | |
| 172 ** Then a WherePath object is a path through the graph that visits some | |
| 173 ** or all of the WhereLoop objects once. | |
| 174 ** | |
| 175 ** The "solver" works by creating the N best WherePath objects of length | |
| 176 ** 1. Then using those as a basis to compute the N best WherePath objects | |
| 177 ** of length 2. And so forth until the length of WherePaths equals the | |
| 178 ** number of nodes in the FROM clause. The best (lowest cost) WherePath | |
| 179 ** at the end is the chosen query plan. | |
| 180 */ | |
| 181 struct WherePath { | |
| 182 Bitmask maskLoop; /* Bitmask of all WhereLoop objects in this path */ | |
| 183 Bitmask revLoop; /* aLoop[]s that should be reversed for ORDER BY */ | |
| 184 LogEst nRow; /* Estimated number of rows generated by this path */ | |
| 185 LogEst rCost; /* Total cost of this path */ | |
| 186 LogEst rUnsorted; /* Total cost of this path ignoring sorting costs */ | |
| 187 i8 isOrdered; /* No. of ORDER BY terms satisfied. -1 for unknown */ | |
| 188 WhereLoop **aLoop; /* Array of WhereLoop objects implementing this path */ | |
| 189 }; | |
| 190 | |
| 191 /* | |
| 192 ** The query generator uses an array of instances of this structure to | |
| 193 ** help it analyze the subexpressions of the WHERE clause. Each WHERE | |
| 194 ** clause subexpression is separated from the others by AND operators, | |
| 195 ** usually, or sometimes subexpressions separated by OR. | |
| 196 ** | |
| 197 ** All WhereTerms are collected into a single WhereClause structure. | |
| 198 ** The following identity holds: | |
| 199 ** | |
| 200 ** WhereTerm.pWC->a[WhereTerm.idx] == WhereTerm | |
| 201 ** | |
| 202 ** When a term is of the form: | |
| 203 ** | |
| 204 ** X <op> <expr> | |
| 205 ** | |
| 206 ** where X is a column name and <op> is one of certain operators, | |
| 207 ** then WhereTerm.leftCursor and WhereTerm.u.leftColumn record the | |
| 208 ** cursor number and column number for X. WhereTerm.eOperator records | |
| 209 ** the <op> using a bitmask encoding defined by WO_xxx below. The | |
| 210 ** use of a bitmask encoding for the operator allows us to search | |
| 211 ** quickly for terms that match any of several different operators. | |
| 212 ** | |
| 213 ** A WhereTerm might also be two or more subterms connected by OR: | |
| 214 ** | |
| 215 ** (t1.X <op> <expr>) OR (t1.Y <op> <expr>) OR .... | |
| 216 ** | |
| 217 ** In this second case, wtFlag has the TERM_ORINFO bit set and eOperator==WO_OR | |
| 218 ** and the WhereTerm.u.pOrInfo field points to auxiliary information that | |
| 219 ** is collected about the OR clause. | |
| 220 ** | |
| 221 ** If a term in the WHERE clause does not match either of the two previous | |
| 222 ** categories, then eOperator==0. The WhereTerm.pExpr field is still set | |
| 223 ** to the original subexpression content and wtFlags is set up appropriately | |
| 224 ** but no other fields in the WhereTerm object are meaningful. | |
| 225 ** | |
| 226 ** When eOperator!=0, prereqRight and prereqAll record sets of cursor numbers, | |
| 227 ** but they do so indirectly. A single WhereMaskSet structure translates | |
| 228 ** cursor number into bits and the translated bit is stored in the prereq | |
| 229 ** fields. The translation is used in order to maximize the number of | |
| 230 ** bits that will fit in a Bitmask. The VDBE cursor numbers might be | |
| 231 ** spread out over the non-negative integers. For example, the cursor | |
| 232 ** numbers might be 3, 8, 9, 10, 20, 23, 41, and 45. The WhereMaskSet | |
| 233 ** translates these sparse cursor numbers into consecutive integers | |
| 234 ** beginning with 0 in order to make the best possible use of the available | |
| 235 ** bits in the Bitmask. So, in the example above, the cursor numbers | |
| 236 ** would be mapped into integers 0 through 7. | |
| 237 ** | |
| 238 ** The number of terms in a join is limited by the number of bits | |
| 239 ** in prereqRight and prereqAll. The default is 64 bits, hence SQLite | |
| 240 ** is only able to process joins with 64 or fewer tables. | |
| 241 */ | |
| 242 struct WhereTerm { | |
| 243 Expr *pExpr; /* Pointer to the subexpression that is this term */ | |
| 244 int iParent; /* Disable pWC->a[iParent] when this term disabled */ | |
| 245 int leftCursor; /* Cursor number of X in "X <op> <expr>" */ | |
| 246 union { | |
| 247 int leftColumn; /* Column number of X in "X <op> <expr>" */ | |
| 248 WhereOrInfo *pOrInfo; /* Extra information if (eOperator & WO_OR)!=0 */ | |
| 249 WhereAndInfo *pAndInfo; /* Extra information if (eOperator& WO_AND)!=0 */ | |
| 250 } u; | |
| 251 LogEst truthProb; /* Probability of truth for this expression */ | |
| 252 u16 eOperator; /* A WO_xx value describing <op> */ | |
| 253 u8 wtFlags; /* TERM_xxx bit flags. See below */ | |
| 254 u8 nChild; /* Number of children that must disable us */ | |
| 255 WhereClause *pWC; /* The clause this term is part of */ | |
| 256 Bitmask prereqRight; /* Bitmask of tables used by pExpr->pRight */ | |
| 257 Bitmask prereqAll; /* Bitmask of tables referenced by pExpr */ | |
| 258 }; | |
| 259 | |
| 260 /* | |
| 261 ** Allowed values of WhereTerm.wtFlags | |
| 262 */ | |
| 263 #define TERM_DYNAMIC 0x01 /* Need to call sqlite3ExprDelete(db, pExpr) */ | |
| 264 #define TERM_VIRTUAL 0x02 /* Added by the optimizer. Do not code */ | |
| 265 #define TERM_CODED 0x04 /* This term is already coded */ | |
| 266 #define TERM_COPIED 0x08 /* Has a child */ | |
| 267 #define TERM_ORINFO 0x10 /* Need to free the WhereTerm.u.pOrInfo object */ | |
| 268 #define TERM_ANDINFO 0x20 /* Need to free the WhereTerm.u.pAndInfo obj */ | |
| 269 #define TERM_OR_OK 0x40 /* Used during OR-clause processing */ | |
| 270 #ifdef SQLITE_ENABLE_STAT3_OR_STAT4 | |
| 271 # define TERM_VNULL 0x80 /* Manufactured x>NULL or x<=NULL term */ | |
| 272 #else | |
| 273 # define TERM_VNULL 0x00 /* Disabled if not using stat3 */ | |
| 274 #endif | |
| 275 | |
| 276 /* | |
| 277 ** An instance of the WhereScan object is used as an iterator for locating | |
| 278 ** terms in the WHERE clause that are useful to the query planner. | |
| 279 */ | |
| 280 struct WhereScan { | |
| 281 WhereClause *pOrigWC; /* Original, innermost WhereClause */ | |
| 282 WhereClause *pWC; /* WhereClause currently being scanned */ | |
| 283 char *zCollName; /* Required collating sequence, if not NULL */ | |
| 284 char idxaff; /* Must match this affinity, if zCollName!=NULL */ | |
| 285 unsigned char nEquiv; /* Number of entries in aEquiv[] */ | |
| 286 unsigned char iEquiv; /* Next unused slot in aEquiv[] */ | |
| 287 u32 opMask; /* Acceptable operators */ | |
| 288 int k; /* Resume scanning at this->pWC->a[this->k] */ | |
| 289 int aEquiv[22]; /* Cursor,Column pairs for equivalence classes */ | |
| 290 }; | |
| 291 | |
| 292 /* | |
| 293 ** An instance of the following structure holds all information about a | |
| 294 ** WHERE clause. Mostly this is a container for one or more WhereTerms. | |
| 295 ** | |
| 296 ** Explanation of pOuter: For a WHERE clause of the form | |
| 297 ** | |
| 298 ** a AND ((b AND c) OR (d AND e)) AND f | |
| 299 ** | |
| 300 ** There are separate WhereClause objects for the whole clause and for | |
| 301 ** the subclauses "(b AND c)" and "(d AND e)". The pOuter field of the | |
| 302 ** subclauses points to the WhereClause object for the whole clause. | |
| 303 */ | |
| 304 struct WhereClause { | |
| 305 WhereInfo *pWInfo; /* WHERE clause processing context */ | |
| 306 WhereClause *pOuter; /* Outer conjunction */ | |
| 307 u8 op; /* Split operator. TK_AND or TK_OR */ | |
| 308 int nTerm; /* Number of terms */ | |
| 309 int nSlot; /* Number of entries in a[] */ | |
| 310 WhereTerm *a; /* Each a[] describes a term of the WHERE cluase */ | |
| 311 #if defined(SQLITE_SMALL_STACK) | |
| 312 WhereTerm aStatic[1]; /* Initial static space for a[] */ | |
| 313 #else | |
| 314 WhereTerm aStatic[8]; /* Initial static space for a[] */ | |
| 315 #endif | |
| 316 }; | |
| 317 | |
| 318 /* | |
| 319 ** A WhereTerm with eOperator==WO_OR has its u.pOrInfo pointer set to | |
| 320 ** a dynamically allocated instance of the following structure. | |
| 321 */ | |
| 322 struct WhereOrInfo { | |
| 323 WhereClause wc; /* Decomposition into subterms */ | |
| 324 Bitmask indexable; /* Bitmask of all indexable tables in the clause */ | |
| 325 }; | |
| 326 | |
| 327 /* | |
| 328 ** A WhereTerm with eOperator==WO_AND has its u.pAndInfo pointer set to | |
| 329 ** a dynamically allocated instance of the following structure. | |
| 330 */ | |
| 331 struct WhereAndInfo { | |
| 332 WhereClause wc; /* The subexpression broken out */ | |
| 333 }; | |
| 334 | |
| 335 /* | |
| 336 ** An instance of the following structure keeps track of a mapping | |
| 337 ** between VDBE cursor numbers and bits of the bitmasks in WhereTerm. | |
| 338 ** | |
| 339 ** The VDBE cursor numbers are small integers contained in | |
| 340 ** SrcList_item.iCursor and Expr.iTable fields. For any given WHERE | |
| 341 ** clause, the cursor numbers might not begin with 0 and they might | |
| 342 ** contain gaps in the numbering sequence. But we want to make maximum | |
| 343 ** use of the bits in our bitmasks. This structure provides a mapping | |
| 344 ** from the sparse cursor numbers into consecutive integers beginning | |
| 345 ** with 0. | |
| 346 ** | |
| 347 ** If WhereMaskSet.ix[A]==B it means that The A-th bit of a Bitmask | |
| 348 ** corresponds VDBE cursor number B. The A-th bit of a bitmask is 1<<A. | |
| 349 ** | |
| 350 ** For example, if the WHERE clause expression used these VDBE | |
| 351 ** cursors: 4, 5, 8, 29, 57, 73. Then the WhereMaskSet structure | |
| 352 ** would map those cursor numbers into bits 0 through 5. | |
| 353 ** | |
| 354 ** Note that the mapping is not necessarily ordered. In the example | |
| 355 ** above, the mapping might go like this: 4->3, 5->1, 8->2, 29->0, | |
| 356 ** 57->5, 73->4. Or one of 719 other combinations might be used. It | |
| 357 ** does not really matter. What is important is that sparse cursor | |
| 358 ** numbers all get mapped into bit numbers that begin with 0 and contain | |
| 359 ** no gaps. | |
| 360 */ | |
| 361 struct WhereMaskSet { | |
| 362 int n; /* Number of assigned cursor values */ | |
| 363 int ix[BMS]; /* Cursor assigned to each bit */ | |
| 364 }; | |
| 365 | |
| 366 /* | |
| 367 ** This object is a convenience wrapper holding all information needed | |
| 368 ** to construct WhereLoop objects for a particular query. | |
| 369 */ | |
| 370 struct WhereLoopBuilder { | |
| 371 WhereInfo *pWInfo; /* Information about this WHERE */ | |
| 372 WhereClause *pWC; /* WHERE clause terms */ | |
| 373 ExprList *pOrderBy; /* ORDER BY clause */ | |
| 374 WhereLoop *pNew; /* Template WhereLoop */ | |
| 375 WhereOrSet *pOrSet; /* Record best loops here, if not NULL */ | |
| 376 #ifdef SQLITE_ENABLE_STAT3_OR_STAT4 | |
| 377 UnpackedRecord *pRec; /* Probe for stat4 (if required) */ | |
| 378 int nRecValid; /* Number of valid fields currently in pRec */ | |
| 379 #endif | |
| 380 }; | |
| 381 | |
| 382 /* | |
| 383 ** The WHERE clause processing routine has two halves. The | |
| 384 ** first part does the start of the WHERE loop and the second | |
| 385 ** half does the tail of the WHERE loop. An instance of | |
| 386 ** this structure is returned by the first half and passed | |
| 387 ** into the second half to give some continuity. | |
| 388 ** | |
| 389 ** An instance of this object holds the complete state of the query | |
| 390 ** planner. | |
| 391 */ | |
| 392 struct WhereInfo { | |
| 393 Parse *pParse; /* Parsing and code generating context */ | |
| 394 SrcList *pTabList; /* List of tables in the join */ | |
| 395 ExprList *pOrderBy; /* The ORDER BY clause or NULL */ | |
| 396 ExprList *pResultSet; /* Result set. DISTINCT operates on these */ | |
| 397 WhereLoop *pLoops; /* List of all WhereLoop objects */ | |
| 398 Bitmask revMask; /* Mask of ORDER BY terms that need reversing */ | |
| 399 LogEst nRowOut; /* Estimated number of output rows */ | |
| 400 u16 wctrlFlags; /* Flags originally passed to sqlite3WhereBegin() */ | |
| 401 i8 nOBSat; /* Number of ORDER BY terms satisfied by indices */ | |
| 402 u8 sorted; /* True if really sorted (not just grouped) */ | |
| 403 u8 okOnePass; /* Ok to use one-pass algorithm for UPDATE/DELETE */ | |
| 404 u8 untestedTerms; /* Not all WHERE terms resolved by outer loop */ | |
| 405 u8 eDistinct; /* One of the WHERE_DISTINCT_* values below */ | |
| 406 u8 nLevel; /* Number of nested loop */ | |
| 407 int iTop; /* The very beginning of the WHERE loop */ | |
| 408 int iContinue; /* Jump here to continue with next record */ | |
| 409 int iBreak; /* Jump here to break out of the loop */ | |
| 410 int savedNQueryLoop; /* pParse->nQueryLoop outside the WHERE loop */ | |
| 411 int aiCurOnePass[2]; /* OP_OpenWrite cursors for the ONEPASS opt */ | |
| 412 WhereMaskSet sMaskSet; /* Map cursor numbers to bitmasks */ | |
| 413 WhereClause sWC; /* Decomposition of the WHERE clause */ | |
| 414 WhereLevel a[1]; /* Information about each nest loop in WHERE */ | |
| 415 }; | |
| 416 | |
| 417 /* | |
| 418 ** Bitmasks for the operators on WhereTerm objects. These are all | |
| 419 ** operators that are of interest to the query planner. An | |
| 420 ** OR-ed combination of these values can be used when searching for | |
| 421 ** particular WhereTerms within a WhereClause. | |
| 422 */ | |
| 423 #define WO_IN 0x001 | |
| 424 #define WO_EQ 0x002 | |
| 425 #define WO_LT (WO_EQ<<(TK_LT-TK_EQ)) | |
| 426 #define WO_LE (WO_EQ<<(TK_LE-TK_EQ)) | |
| 427 #define WO_GT (WO_EQ<<(TK_GT-TK_EQ)) | |
| 428 #define WO_GE (WO_EQ<<(TK_GE-TK_EQ)) | |
| 429 #define WO_MATCH 0x040 | |
| 430 #define WO_ISNULL 0x080 | |
| 431 #define WO_OR 0x100 /* Two or more OR-connected terms */ | |
| 432 #define WO_AND 0x200 /* Two or more AND-connected terms */ | |
| 433 #define WO_EQUIV 0x400 /* Of the form A==B, both columns */ | |
| 434 #define WO_NOOP 0x800 /* This term does not restrict search space */ | |
| 435 | |
| 436 #define WO_ALL 0xfff /* Mask of all possible WO_* values */ | |
| 437 #define WO_SINGLE 0x0ff /* Mask of all non-compound WO_* values */ | |
| 438 | |
| 439 /* | |
| 440 ** These are definitions of bits in the WhereLoop.wsFlags field. | |
| 441 ** The particular combination of bits in each WhereLoop help to | |
| 442 ** determine the algorithm that WhereLoop represents. | |
| 443 */ | |
| 444 #define WHERE_COLUMN_EQ 0x00000001 /* x=EXPR */ | |
| 445 #define WHERE_COLUMN_RANGE 0x00000002 /* x<EXPR and/or x>EXPR */ | |
| 446 #define WHERE_COLUMN_IN 0x00000004 /* x IN (...) */ | |
| 447 #define WHERE_COLUMN_NULL 0x00000008 /* x IS NULL */ | |
| 448 #define WHERE_CONSTRAINT 0x0000000f /* Any of the WHERE_COLUMN_xxx values */ | |
| 449 #define WHERE_TOP_LIMIT 0x00000010 /* x<EXPR or x<=EXPR constraint */ | |
| 450 #define WHERE_BTM_LIMIT 0x00000020 /* x>EXPR or x>=EXPR constraint */ | |
| 451 #define WHERE_BOTH_LIMIT 0x00000030 /* Both x>EXPR and x<EXPR */ | |
| 452 #define WHERE_IDX_ONLY 0x00000040 /* Use index only - omit table */ | |
| 453 #define WHERE_IPK 0x00000100 /* x is the INTEGER PRIMARY KEY */ | |
| 454 #define WHERE_INDEXED 0x00000200 /* WhereLoop.u.btree.pIndex is valid */ | |
| 455 #define WHERE_VIRTUALTABLE 0x00000400 /* WhereLoop.u.vtab is valid */ | |
| 456 #define WHERE_IN_ABLE 0x00000800 /* Able to support an IN operator */ | |
| 457 #define WHERE_ONEROW 0x00001000 /* Selects no more than one row */ | |
| 458 #define WHERE_MULTI_OR 0x00002000 /* OR using multiple indices */ | |
| 459 #define WHERE_AUTO_INDEX 0x00004000 /* Uses an ephemeral index */ | |
| 460 #define WHERE_SKIPSCAN 0x00008000 /* Uses the skip-scan algorithm */ | |
| 461 #define WHERE_UNQ_WANTED 0x00010000 /* WHERE_ONEROW would have been helpful*/ | |
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Chromium Code Reviews
Issue 2363173002:
[sqlite] Remove obsolete reference version 3.8.7.4. (Closed)
