From: dan Date: Fri, 17 Jun 2016 19:27:13 +0000 (+0000) Subject: Include WHERE terms in the cursor-hint passed to a cursor opened for the rhs of a... X-Git-Tag: version-3.14.0~93^2~1 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=e6912fd8198b3693932bc0ddaffc423a8cec417f;p=thirdparty%2Fsqlite.git Include WHERE terms in the cursor-hint passed to a cursor opened for the rhs of a LEFT JOIN iff we can be sure that those terms will not evaluate to true if the LEFT JOIN generates a row of NULLs. FossilOrigin-Name: 998095aba01b75f685ed981b377e1dfe650d9bbf --- diff --git a/manifest b/manifest index 788c218d3b..be6f9cf0da 100644 --- a/manifest +++ b/manifest @@ -1,5 +1,5 @@ -C Fix\sa\sduplicate\stest\sname\sin\scursorhint2.test. -D 2016-06-17T14:59:40.619 +C Include\sWHERE\sterms\sin\sthe\scursor-hint\spassed\sto\sa\scursor\sopened\sfor\sthe\srhs\sof\sa\sLEFT\sJOIN\siff\swe\scan\sbe\ssure\sthat\sthose\sterms\swill\snot\sevaluate\sto\strue\sif\sthe\sLEFT\sJOIN\sgenerates\sa\srow\sof\sNULLs. +D 2016-06-17T19:27:13.114 F Makefile.in f3f7d2060ce03af4584e711ef3a626ef0b1d6340 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434 F Makefile.msc 50149765ef72f4e652b9a0f1f6462c4784bb9423 @@ -464,7 +464,7 @@ F src/wal.h 2f7c831cf3b071fa548bf2d5cac640846a7ff19c F src/walker.c 0f142b5bd3ed2041fc52d773880748b212e63354 F src/where.c 74f0798525b6306682d7234f230ea93f86959b9b F src/whereInt.h e5b939701a7ceffc5a3a8188a37f9746416ebcd0 -F src/wherecode.c b9d5f7d8ebed2e09376fd785a111ffd9dfd59ffc +F src/wherecode.c c1b11ad09468577afd3c36cd8c854fb6dd77f258 F src/whereexpr.c c32d47085dbaca0b8fd013210f56693c7d220d48 F test/8_3_names.test ebbb5cd36741350040fd28b432ceadf495be25b2 F test/affinity2.test a6d901b436328bd67a79b41bb0ac2663918fe3bd @@ -617,7 +617,7 @@ F test/cse.test 277350a26264495e86b1785f34d2d0c8600e021c F test/csv01.test 0929a9ce47021519512be92861f29e32d2538e5f F test/ctime.test 7bd009071e242aac4f18521581536b652b789a47 F test/cursorhint.test 7bc346788390475e77a345da2b92270d04d35856 -F test/cursorhint2.test aa52c25d84366531af871f0bed91a7147b2b37e8 +F test/cursorhint2.test cef69bab25b9141071b4239fa5c3b4ce18eeafd0 F test/date.test 984ac1e3e5e031386866f034006148d3972b4a65 F test/dbstatus.test 8de104bb5606f19537d23cd553b41349b5ab1204 F test/dbstatus2.test e93ab03bfae6d62d4d935f20de928c19ca0ed0ab @@ -1502,7 +1502,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0 -P c1a5a57cf10dca91082963dcbd3e3ffebc3707ef -R ae6a6e72981ae73e95b7048747b6cd4f +P fcd12b69cee1335224a65aa6d22c4e302b889398 +R aa7c436ce5d8105be03298dc84afa8de U dan -Z 130058fba07c74a7ae7dc91c3a4fa1a9 +Z a2cf93e232f8c6f0bcf6400999626f67 diff --git a/manifest.uuid b/manifest.uuid index 8c6ce154cd..efb8ac0335 100644 --- a/manifest.uuid +++ b/manifest.uuid @@ -1 +1 @@ -fcd12b69cee1335224a65aa6d22c4e302b889398 \ No newline at end of file +998095aba01b75f685ed981b377e1dfe650d9bbf \ No newline at end of file diff --git a/src/wherecode.c b/src/wherecode.c index 94139b6543..e6294de532 100644 --- a/src/wherecode.c +++ b/src/wherecode.c @@ -626,6 +626,31 @@ static int codeCursorHintCheckExpr(Walker *pWalker, Expr *pExpr){ return WRC_Continue; } +/* +** Test whether or not expression pExpr, which was part of a WHERE clause, +** should be included in the cursor-hint for a table that is on the rhs +** of a LEFT JOIN. Set Walker.eCode to non-zero before returning if the +** expression is not suitable. +** +** An expression is unsuitable if it might evaluate to non NULL even if +** a TK_COLUMN node that does affect the value of the expression is set +** to NULL. For example: +** +** col IS NULL +** col IS NOT NULL +** coalesce(col, 1) +** CASE WHEN col THEN 0 ELSE 1 END +*/ +static int codeCursorHintIsOrFunction(Walker *pWalker, Expr *pExpr){ + if( pExpr->op==TK_IS || pExpr->op==TK_FUNCTION + || pExpr->op==TK_ISNULL || pExpr->op==TK_ISNOT + || pExpr->op==TK_NOTNULL || pExpr->op==TK_CASE + ){ + pWalker->eCode = 1; + } + return WRC_Continue; +} + /* ** This function is called on every node of an expression tree used as an @@ -714,22 +739,33 @@ static void codeCursorHint( ** JOIN for which the current table is not the rhs are omitted ** from the cursor-hint. ** - ** If this table is the rhs of a LEFT JOIN, only terms that were - ** specified as part of the ON(...) clause may be included in the - ** hint. This is to address the following: + ** If this table is the rhs of a LEFT JOIN, "IS" or "IS NULL" terms + ** that were specified as part of the WHERE clause must be excluded. + ** This is to address the following: ** ** SELECT ... t1 LEFT JOIN t2 ON (t1.a=t2.b) WHERE t2.c IS NULL; ** - ** If the (t2.c IS NULL) constraint is pushed down to the cursor, it - ** might filter out all rows that match (t1.a=t2.b), causing SQLite - ** to add a row of NULL values to the output that should not be - ** present (since the ON clause does actually match rows within t2). + ** Say there is a single row in t2 that matches (t1.a=t2.b), but its + ** t2.c values is not NULL. If the (t2.c IS NULL) constraint is + ** pushed down to the cursor, this row is filtered out, causing + ** SQLite to synthesize a row of NULL values. Which does match the + ** WHERE clause, and so the query returns a row. Which is incorrect. + ** + ** For the same reason, WHERE terms such as: + ** + ** WHERE 1 = (t2.c IS NULL) + ** + ** are also excluded. See codeCursorHintIsOrFunction() for details. */ if( pTabItem->fg.jointype & JT_LEFT ){ - if( !ExprHasProperty(pTerm->pExpr, EP_FromJoin) - || pTerm->pExpr->iRightJoinTable!=pTabItem->iCursor + Expr *pExpr = pTerm->pExpr; + if( !ExprHasProperty(pExpr, EP_FromJoin) + || pExpr->iRightJoinTable!=pTabItem->iCursor ){ - continue; + sWalker.eCode = 0; + sWalker.xExprCallback = codeCursorHintIsOrFunction; + sqlite3WalkExpr(&sWalker, pTerm->pExpr); + if( sWalker.eCode ) continue; } }else{ if( ExprHasProperty(pTerm->pExpr, EP_FromJoin) ) continue; diff --git a/test/cursorhint2.test b/test/cursorhint2.test index b6ebda2244..b42227cdfb 100644 --- a/test/cursorhint2.test +++ b/test/cursorhint2.test @@ -94,7 +94,74 @@ do_extract_hints_test 1.6 { do_extract_hints_test 1.7 { SELECT * FROM t1 LEFT JOIN t2 ON (a=c AND d=e) LEFT JOIN t3 ON (d=f); } { - t2 {EQ(r[2],c0)} t3 {EQ(r[6],c1)} + t2 {EQ(r[2],c0)} t3 {AND(EQ(r[6],c0),EQ(r[7],c1))} +} + +#------------------------------------------------------------------------- +# +do_execsql_test 2.0 { + CREATE TABLE x1(x, y); + CREATE TABLE x2(a, b); +} + +do_extract_hints_test 2.1 { + SELECT * FROM x1 LEFT JOIN x2 ON (a=x) WHERE b IS NULL; +} { + x2 {EQ(c0,r[2])} +} + +do_extract_hints_test 2.2 { + SELECT * FROM x1 LEFT JOIN x2 ON (a=x) WHERE b IS +NULL; +} { + x2 {EQ(c0,r[2])} +} + +do_extract_hints_test 2.3 { + SELECT * FROM x1 LEFT JOIN x2 ON (a=x) WHERE 1 = (b IS NULL) +} { + x2 {EQ(c0,r[2])} +} + +do_extract_hints_test 2.4 { + SELECT * FROM x1 LEFT JOIN x2 ON (a=x) WHERE 1 = coalesce(b, 1) +} { + x2 {EQ(c0,r[2])} +} + +do_extract_hints_test 2.5 { + SELECT * FROM x1 LEFT JOIN x2 ON (a=x) WHERE 1 = coalesce(b, 1) +} { + x2 {EQ(c0,r[2])} +} + +do_extract_hints_test 2.6 { + SELECT * FROM x1 LEFT JOIN x2 ON (a=x) WHERE 0 = (b IS NOT NULL) +} { + x2 {EQ(c0,r[2])} +} + +do_extract_hints_test 2.7 { + SELECT * FROM x1 LEFT JOIN x2 ON (a=x) WHERE 0 = (b IS NOT +NULL) +} { + x2 {EQ(c0,r[2])} +} + +do_extract_hints_test 2.8 { + SELECT * FROM x1 LEFT JOIN x2 ON (a=x) WHERE b IS NOT +NULL +} { + x2 {EQ(c0,r[2])} +} + +do_extract_hints_test 2.9 { + SELECT * FROM x1 LEFT JOIN x2 ON (a=x) WHERE CASE b WHEN 0 THEN 0 ELSE 1 END; +} { + x2 {EQ(c0,r[2])} +} + +do_extract_hints_test 2.10 { + SELECT * FROM x1 LEFT JOIN x2 ON (a=x) WHERE x2.b = 32+32 +} { + x2 {AND(EQ(c1,ADD(32,32)),EQ(c0,r[2]))} } finish_test