-C Fix\sa\sbuffer\soverread\sin\sfts5.
-D 2018-07-25T15:25:55.074
+C Initial\simplementation\sof\sthe\sWHERE-clause\sconstant\spropagation\soptimization.
+D 2018-07-26T21:16:53.742
F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
F Makefile.in 0a3a6c81e6fcb969ff9106e882f0a08547014ba463cb6beca4c4efaecc924ee6
F src/random.c 80f5d666f23feb3e6665a6ce04c7197212a88384
F src/resolve.c 797088662ed61102485e3070ba3b3f7828bd5ef6a588223ba6865d77d52f6cea
F src/rowset.c 7b7e7e479212e65b723bf40128c7b36dc5afdfac
-F src/select.c 2e9661d4424f43ccf595c4a7b4acdf32db523c0f6b31cbd62e6e5a2f43118981
+F src/select.c cd3993844ab1186e80069f9de2304e730732cfea1f718e603293792d4401d037
F src/shell.c.in f6ebd05c461805a7c708333cd645e74e0a93560d2118f5adb73a75d8c9cf6b01
F src/sqlite.h.in c6451bb876adced3aba5b1682c6317d215c5eceaba21a6ce979e71a0b8d0bf95
F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
F src/sqlite3ext.h 9887b27e69c01e79c2cbe74ef73bf01af5b5703d6a7f0a4371e386d7249cb1c7
-F src/sqliteInt.h 427471586351daefbc81155384a702b2173801051fe345bc25a09558b919db77
+F src/sqliteInt.h 0da0d929642cacf99963e406d34e2e3be891a30168f99aefc1cb81c2c545a09b
F src/sqliteLimit.h 1513bfb7b20378aa0041e7022d04acb73525de35b80b252f1b83fedb4de6a76b
F src/status.c 46e7aec11f79dad50965a5ca5fa9de009f7d6bde08be2156f1538a0a296d4d0e
F src/table.c b46ad567748f24a326d9de40e5b9659f96ffff34
F test/whereI.test b7769ee8dbefd987fb266715fee887f05f9ff180016b06fca7fa402df739193b
F test/whereJ.test 88287550f6ee604422403b053455b1ad894eeaa5c35d348532dfa1439286cb9a
F test/whereK.test f8e3cf26a8513ecc7f514f54df9f0572c046c42b
+F test/whereL.test 46492cf4b3b2bfa5bb8adb8d6565f31c010bf8f23baf66bcba4e38cec89117a2
F test/wherefault.test 1374c3aa198388925246475f84ad4cd5f9528864
F test/wherelfault.test 9012e4ef5259058b771606616bd007af5d154e64cc25fa9fd4170f6411db44e3
F test/wherelimit.test 592081800806d297dd7449b1030c863d2883d6d42901837ccd2e5a9bd962edb0
F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 6ee2950b272ede475e485bfaa7d413eaa81482fe9dd6452aeeaf95ff7938f7da
-R b452b7474ada2f7df230e94f47eaea02
-U dan
-Z 3eecc6d8fc02fe02d8a834ac76aa6a16
+P 0e3de8abbb0c7ae64e637776cb055ce79736f99a103e00e44d17a6b091b98c81
+R 83557e363f35588e2f481ff35d0d8054
+T *branch * propagate-const-opt
+T *sym-propagate-const-opt *
+T -sym-trunk *
+U drh
+Z 8488ca3ac81dbe859bc19508bb265e68
}
#endif /* !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW) */
+/*
+** A structure to keep track of all of the column values that must be
+** constant in a WHERE clause.
+*/
+typedef struct WhereConst WhereConst;
+struct WhereConst {
+ sqlite3 *db; /* Database pointer, used by sqlite3DbRealloc() */
+ int nConst; /* Number for COLUMN=CONSTANT terms */
+ int nChng; /* Number of times a constant is propagated */
+ Expr **apExpr; /* [i*2] is COLUMN and [i*2+1] is CONSTANT */
+};
+
+/*
+** Add a new entry to the pConst object
+*/
+static void constInsert(
+ WhereConst *pConst,
+ Expr *pColumn,
+ Expr *pValue
+){
+ pConst->nConst++;
+ pConst->apExpr = sqlite3DbReallocOrFree(pConst->db, pConst->apExpr,
+ pConst->nConst*2*sizeof(Expr*));
+ if( pConst->apExpr==0 ){
+ pConst->nConst = 0;
+ }else{
+ pConst->apExpr[pConst->nConst*2-2] = pColumn;
+ pConst->apExpr[pConst->nConst*2-1] = pValue;
+ }
+}
+
+/*
+** Find all instances of COLUMN=CONSTANT or CONSTANT=COLUMN in pExpr that
+** must be true (that are part of the AND-connected terms) and add each
+** to pConst.
+*/
+static void findConstInWhere(WhereConst *pConst, Expr *pExpr){
+ if( pExpr==0 ) return;
+ if( ExprHasProperty(pExpr, EP_FromJoin) ) return;
+ if( pExpr->op==TK_AND ){
+ findConstInWhere(pConst, pExpr->pRight);
+ findConstInWhere(pConst, pExpr->pLeft);
+ return;
+ }
+ if( pExpr->op!=TK_EQ ) return;
+ assert( pExpr->pRight!=0 );
+ assert( pExpr->pLeft!=0 );
+ if( pExpr->pRight->op==TK_COLUMN && sqlite3ExprIsConstant(pExpr->pLeft) ){
+ constInsert(pConst, pExpr->pRight, pExpr->pLeft);
+ }else
+ if( pExpr->pLeft->op==TK_COLUMN && sqlite3ExprIsConstant(pExpr->pRight) ){
+ constInsert(pConst, pExpr->pLeft, pExpr->pRight);
+ }
+}
+
+/*
+** This is a Walker expression callback. pExpr is a candidate expression
+** to be replaced by a value. If pExpr is equivalent to one of the
+** columns named in pWalker->u.pConst, then overwrite it with its
+** corresponding value.
+*/
+static int propagateConstantExprRewrite(Walker *pWalker, Expr *pExpr){
+ int i;
+ WhereConst *pConst;
+ if( pExpr->op!=TK_COLUMN ) return WRC_Continue;
+ pConst = pWalker->u.pConst;
+ for(i=0; i<pConst->nConst; i++){
+ Expr *pColumn = pConst->apExpr[i*2];
+ if( pColumn==pExpr ) continue;
+ if( pColumn->iTable!=pExpr->iTable ) continue;
+ if( pColumn->iColumn!=pExpr->iColumn ) continue;
+ /* A match is found. Transform the COLUMN into a CONSTANT */
+ pConst->nChng++;
+ ExprClearProperty(pExpr, EP_Leaf);
+ pExpr->op = TK_UPLUS;
+ pExpr->pLeft = sqlite3ExprDup(pConst->db, pConst->apExpr[i*2+1], 0);
+ break;
+ }
+ return WRC_Prune;
+}
+/*
+** The WHERE-clause constant propagation optimization.
+**
+** If the WHERE clause contains terms of the form COLUMN=CONSTANT or
+** CONSTANT=COLUMN that must be tree (in other words, if the terms top-level
+** AND-connected terms that are not part of a ON clause from a LEFT JOIN)
+** then throughout the query replace all other occurrences of COLUMN
+** with CONSTANT.
+**
+** For example, the query:
+**
+** SELECT * FROM t1, t2, t3 WHERE t1.a=39 AND t2.b=t1.a AND t3.c=t2.b
+**
+** Is transformed into
+**
+** SELECT * FROM t1, t2, t3 WHERE t1.a=39 AND t2.b=39 AND t3.c=39
+**
+** Return true if any transformations where made and false if not.
+*/
+static int propagateConstants(
+ Parse *pParse, /* The parsing context */
+ Select *p /* The query in which to propagate constants */
+){
+ WhereConst x;
+ Walker w;
+ int nChng = 0;
+ x.db = pParse->db;
+ do{
+ x.nConst = 0;
+ x.nChng = 0;
+ x.apExpr = 0;
+ findConstInWhere(&x, p->pWhere);
+ if( x.nConst ){
+ memset(&w, 0, sizeof(w));
+ w.pParse = pParse;
+ w.xExprCallback = propagateConstantExprRewrite;
+ w.xSelectCallback = sqlite3SelectWalkNoop;
+ w.xSelectCallback2 = 0;
+ w.walkerDepth = 0;
+ w.u.pConst = &x;
+ sqlite3WalkSelect(&w, p);
+ sqlite3DbFree(x.db, x.apExpr);
+ nChng += x.nChng;
+ }
+ }while( x.nChng );
+ return nChng;
+}
#if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
/*
*/
pParse->nHeight += sqlite3SelectExprHeight(p);
+ /* Do the constant propagation optimization */
+ if( OptimizationEnabled(db, SQLITE_PropagateConst)
+ && propagateConstants(pParse, p)
+ ){
+#if SELECTTRACE_ENABLED
+ if( sqlite3SelectTrace & 0x100 ){
+ SELECTTRACE(0x100,pParse,p,("After constant propagation:\n"));
+ sqlite3TreeViewSelect(0, p, 0);
+ }
+#endif
+ }else{
+ SELECTTRACE(0x100,pParse,p,("Constant propagation not possible\n"));
+ }
+
/* Make copies of constant WHERE-clause terms in the outer query down
** inside the subquery. This can help the subquery to run more efficiently.
*/
--- /dev/null
+# 2018-07-26
+#
+# The author disclaims copyright to this source code. In place of
+# a legal notice, here is a blessing:
+#
+# May you do good and not evil.
+# May you find forgiveness for yourself and forgive others.
+# May you share freely, never taking more than you give.
+#
+#***********************************************************************
+# This file implements regression tests for SQLite library. The
+# focus of this file is testing the WHERE-clause constant propagation
+# optimization.
+#
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+set ::testprefix whereL
+
+do_execsql_test 100 {
+ CREATE TABLE t1(a INT PRIMARY KEY, b, c, d, e);
+ CREATE TABLE t2(a INT PRIMARY KEY, f, g, h, i);
+ CREATE TABLE t3(a INT PRIMARY KEY, j, k, l, m);
+ CREATE VIEW v4 AS SELECT * FROM t2 UNION ALL SELECT * FROM t3;
+}
+do_eqp_test 110 {
+ SELECT * FROM t1, v4 WHERE t1.a=?1 AND v4.a=t1.a;
+} {
+ QUERY PLAN
+ |--MATERIALIZE xxxxxx
+ | `--COMPOUND QUERY
+ | |--LEFT-MOST SUBQUERY
+ | | `--SEARCH TABLE t2 USING INDEX sqlite_autoindex_t2_1 (a=?)
+ | `--UNION ALL
+ | `--SEARCH TABLE t3 USING INDEX sqlite_autoindex_t3_1 (a=?)
+ |--SCAN SUBQUERY xxxxxx
+ `--SEARCH TABLE t1 USING INDEX sqlite_autoindex_t1_1 (a=?)
+}
+
+finish_test
projects / thirdparty / sqlite.git / commitdiff
