Remove the column-cache from the code generator. The column-cache has been

a persistent source of bugs for years and with recent improvements
in the performance of OP_Column, it no longer provides a benefit.  After
the column cache is removed, the binary is almost 2KB smaller and the
speed-check.sh performance test is over 3 million cycles faster.

FossilOrigin-Name: cdff3af7bedc5ebea04bd9b5e2112d3db451a475c18c9a9ebd45f6f3a89a43cb

manifest

@@ -1,5 +1,5 @@
-C Add\stest\scases\sfor\sthe\sconstant\sexpression\sfix\sof\sthe\sprevious\scheck-in.
+C Remove\sthe\scolumn-cache\sfrom\sthe\scode\sgenerator.\s\sThe\scolumn-cache\shas\sbeen\na\spersistent\ssource\sof\sbugs\sfor\syears\sand\swith\srecent\simprovements\nin\sthe\sperformance\sof\sOP_Column,\sit\sno\slonger\sprovides\sa\sbenefit.\s\sAfter\nthe\scolumn\scache\sis\sremoved,\sthe\sbinary\sis\salmost\s2KB\ssmaller\sand\sthe\nspeed-check.sh\sperformance\stest\sis\sover\s3\smillion\scycles\sfaster.
-D 2018-08-04T15:28:12.613
+D 2018-08-04T20:30:55.322
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F Makefile.in 0a3a6c81e6fcb969ff9106e882f0a08547014ba463cb6beca4c4efaecc924ee6
@@ -442,15 +442,15 @@ F src/btmutex.c 8acc2f464ee76324bf13310df5692a262b801808984c1b79defb2503bbafadb6
 F src/btree.c 3f5e1a03db871e627bf5da21092bf7434ecfc5c5980bbd7d45eba13341340173
 F src/btree.h febb2e817be499570b7a2e32a9bbb4b607a9234f6b84bb9ae84916d4806e96f2
 F src/btreeInt.h 620ab4c7235f43572cf3ac2ac8723cbdf68073be4d29da24897c7b77dda5fd96
-F src/build.c 7e82726057d67de1d77961f3a3f371353171099bb6b006adb172b6d3aebb1d4a
+F src/build.c fe407be13d1201bf386d2c629424e5c97a07bcfc6ef21cf6e888e50b792a6191
 F src/callback.c 36caff1e7eb7deb58572d59c41cee8f064a11d00297616995c5050ea0cfc1288
 F src/complete.c a3634ab1e687055cd002e11b8f43eb75c17da23e
 F src/ctime.c b157b01081f92442f8b0218ddb93ddce8ebddad36dbddeecfdd771561dd4f387
 F src/date.c ebe1dc7c8a347117bb02570f1a931c62dd78f4a2b1b516f4837d45b7d6426957
 F src/dbpage.c 4aa7f26198934dbd002e69418220eae3dbc71b010bbac32bd78faf86b52ce6c3
 F src/dbstat.c edabb82611143727511a45ca0859b8cd037851ebe756ae3db289859dd18b6f91
-F src/delete.c 4c8c7604277a2041647f96b78f4b9a47858e9217e4fb333d35e7b5ab32c5b57f
+F src/delete.c 107e28d3ef8bd72fd11953374ca9107cd74e8b09c3ded076a6048742d26ce7d2
-F src/expr.c 825198653fb655df3d758c556eb003f0a531a3661d0573cf445b4e9298daac07
+F src/expr.c aac1c33ef8899d0cfe32e4269810e10372f8fdbce6554b38034973d5e8c285d9
 F src/fault.c 460f3e55994363812d9d60844b2a6de88826e007
 F src/fkey.c f59253c0be4b1e9dfcb073b6d6d6ab83090ae50c08b5c113b76013c4b157cd6a
 F src/func.c 7c288b4ce309b5a8b8473514b88e1f8e69a80134509a8c0db8e39c858e367e7f
@@ -459,7 +459,7 @@ F src/hash.c a12580e143f10301ed5166ea4964ae2853d3905a511d4e0c44497245c7ce1f7a
 F src/hash.h ab34c5c54a9e9de2e790b24349ba5aab3dbb4fd4
 F src/hwtime.h 747c1bbe9df21a92e9c50f3bbec1de841dc5e5da
 F src/in-operator.md 10cd8f4bcd225a32518407c2fb2484089112fd71
-F src/insert.c 8613af9c5ba1503bc68f4e9432c6c024e0fdafdc791575c50f380f73ec91189f
+F src/insert.c 894594952bcda1dc6e1549871e4022517563545ffc7a3f4e9e5f3faa788893fd
 F src/legacy.c 134ab3e3fae00a0f67a5187981d6935b24b337bcf0f4b3e5c9fa5763da95bf4e
 F src/loadext.c 6aae5739198d96c51ae6eb97c4a5b1744c22ed7a5a565a5399a717780d48a36b
 F src/main.c dc023f468eda20aed1fb7c300673cbb40617607b5771840e4229ec239dade250
@@ -491,24 +491,24 @@ F src/parse.y 704c94624d41d7d46a5467574130e55aa8029a563f4df538f0121475eae46e34
 F src/pcache.c 135ef0bc6fb2e3b7178d49ab5c9176254c8a691832c1bceb1156b2fbdd0869bd
 F src/pcache.h 072f94d29281cffd99e46c1539849f248c4b56ae7684c1f36626797fee375170
 F src/pcache1.c 716975564c15eb6679e97f734cec1bfd6c16ac3d4010f05f1f8e509fc7d19880
-F src/pragma.c 71c585f1d26e14b931fa4573f587933d6dfddecd9d9001b0f126f74f7306bf87
+F src/pragma.c 873b767f233932e97cbffd094aa61928be90aca03f946a94bb29ce5695e4885b
 F src/pragma.h bb83728944b42f6d409c77f5838a8edbdb0fe83046c5496ffc9602b40340a324
 F src/prepare.c e966ecc97c3671ff0e96227c8c877b83f2d33ea371ee190bbf1698b36b5605c0
 F src/printf.c 7f6f3cba8e0c49c19e30a1ff4e9aeda6e06814dcbad4b664a69e1b6cb6e7e365
 F src/random.c 80f5d666f23feb3e6665a6ce04c7197212a88384
 F src/resolve.c 797088662ed61102485e3070ba3b3f7828bd5ef6a588223ba6865d77d52f6cea
 F src/rowset.c 7b7e7e479212e65b723bf40128c7b36dc5afdfac
-F src/select.c 18636c49eeb9016bb429ac6892220aea51bc618d021cf16770146e1858cf6f1e
+F src/select.c ae7396a314cc1bb1d767947cd57094e3a9ffcbb155ebc1b1c391e028c44a9a04
 F src/shell.c.in 5e4c139799f059a5231f0259111f51f6dffcb28154c535f6b4c2192619a40844
 F src/sqlite.h.in c6451bb876adced3aba5b1682c6317d215c5eceaba21a6ce979e71a0b8d0bf95
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
 F src/sqlite3ext.h 9887b27e69c01e79c2cbe74ef73bf01af5b5703d6a7f0a4371e386d7249cb1c7
-F src/sqliteInt.h de37aae03c6a4e4f1e1eff15c04292153dbba015ad8e0dc0dffe82ea0fe76d5e
+F src/sqliteInt.h a5d212bb7ae5cfc0540af6fb09eee2092a45fe083fac4191ee64ff70e7d4d78a
 F src/sqliteLimit.h 1513bfb7b20378aa0041e7022d04acb73525de35b80b252f1b83fedb4de6a76b
 F src/status.c 46e7aec11f79dad50965a5ca5fa9de009f7d6bde08be2156f1538a0a296d4d0e
 F src/table.c b46ad567748f24a326d9de40e5b9659f96ffff34
 F src/tclsqlite.c e0bf71a6d24b8c23393c000abffab05979bbca2a72d0b0f79260e2cf1527fda5
-F src/test1.c 335740ddc632c0b54765b6fd373da7f76a397adde3ded3592390dd1e5fb0dd55
+F src/test1.c 55424c026dd93c06ad84ff4e46cec64aa3e12e767d50c31886e6a69ee53fe81e
 F src/test2.c 3efb99ab7f1fc8d154933e02ae1378bac9637da5
 F src/test3.c 61798bb0d38b915067a8c8e03f5a534b431181f802659a6616f9b4ff7d872644
 F src/test4.c 18ec393bb4d0ad1de729f0b94da7267270f3d8e6
@@ -564,18 +564,18 @@ F src/threads.c 4ae07fa022a3dc7c5beb373cf744a85d3c5c6c3c
 F src/tokenize.c 01e96d1b639c3eb0b9ef90616e766d453935c554f1f7aa86b6db937b79554b97
 F src/treeview.c e7a7f90552bb418533cdd0309b5eb71d4effa50165b880fc8c2001e613577e5f
 F src/trigger.c 4ace6d1d5ba9a89822deb287317f33c810440526eafe185c2d8a48c31df1e995
-F src/update.c 7b7c768dc415a8d2eb9fd2cea8b524cb29cf354f319700e22f94f262d3f507cb
+F src/update.c 345ce35eb1332eb4829857aa8b1f65a614b07dae91d0346c0dc2baacafbcc51b
 F src/upsert.c 47edd408cc73f8d3c00a140550d1ad180b407c146285947969dd09874802bf88
 F src/utf.c 810fbfebe12359f10bc2a011520a6e10879ab2a163bcb26c74768eab82ea62a5
 F src/util.c d9eb0a6c4aae1b00a7369eadd7ca0bbe946cb4c953b6751aa20d357c2f482157
 F src/vacuum.c 36e7d21a20c0bf6ef4ef7c399d192b5239410b7c4d3c1070fba4e30810d0b855
-F src/vdbe.c 8fbefa50884f4803139bdc2d4795b973a1a892f023726fa72246fea2fe8e9925
+F src/vdbe.c 8744e9e830262867a9730ca487a114abc7265b572b48f80b18124d1d347f7b1b
 F src/vdbe.h d93abdc8bc9295e0a256e582c19f548c545dc498319d108bbc9dd29de31c48a2
-F src/vdbeInt.h 2a45270d7f44870ca5452f48cdf3c56387019ae03331c008d670a7d0a3e1ba3f
+F src/vdbeInt.h 8ea493d994c6697cf7bccc60583a80a0222560490410f60f1113e90d36643ce0
-F src/vdbeapi.c af4a3de00d1851bcbc55b85dfbe52849aa2b1e17b4a5a1f3d9c257df7af361ff
+F src/vdbeapi.c 2ba821c5929a2769e4b217dd85843479c718b8989d414723ec8af0616a83d611
-F src/vdbeaux.c 1265a36260c36eb55afb40d744ffc1a3f11252d5712274c6218efb087204a7e5
+F src/vdbeaux.c b610cef3d8d381c9287d02c2e61590acc0a1b4de1cc0188d560f5ef345527a24
 F src/vdbeblob.c f5c70f973ea3a9e915d1693278a5f890dc78594300cf4d54e64f2b0917c94191
-F src/vdbemem.c a699a1d7ccc3f94cdff69ddf35d5f7540dbf52ca44cf040eda3c87520e67858c
+F src/vdbemem.c 720df42ad8e5c7cb883573de40a185afef4a214903098a16f2bb14b62b2399b7
 F src/vdbesort.c 731a09e5cb9e96b70c394c1b7cf3860fbe84acca7682e178615eb941a3a0ef2f
 F src/vdbetrace.c 79d6dbbc479267b255a7de8080eee6e729928a0ef93ed9b0bfa5618875b48392
 F src/vtab.c 678992ac8ec677a3f9b08126aaf891441083805e3b42574e3654d44538381c14
@@ -583,9 +583,9 @@ F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
 F src/wal.c d44a0811afd2155b1157c38b33141d4ac028fda6232485bed664015bb05819ca
 F src/wal.h 8de5d2d3de0956d6f6cb48c83a4012d5f227b8fe940f3a349a4b7e85ebcb492a
 F src/walker.c ba7225773931760cf60bf22f34d0cce2588df7ce5ce0f215a52eb88234b55ac4
-F src/where.c 52ab6d07a6ac6e2cb2a7da41217f0b7c13ce17a30d6a1d3459e86ac94b160e15
+F src/where.c 155809967fbab889374dedf970ea6561b8fb519fcb165d6ba00776552ecc5cde
 F src/whereInt.h b90ef9b9707ef750eab2a7a080c48fb4900315033274689def32d0cf5a81ebe4
-F src/wherecode.c eb558ea9a482e179d27858113ca7012e508b904ff90b892367cc9ca4c0b9b246
+F src/wherecode.c 2b6cd1b27736cc803060289e04ecf9849976106f4077aa67d1a2c0e3ec420159
 F src/whereexpr.c dc34f0df69418dedb4619f7ad61b7d31f447971223540b957a1b836a62c0ce7b
 F src/window.c 4b503da928dace3e845b891381a4d98eeb8c5744313ae3643df8d8d21fdcca65
 F test/8_3_names.test ebbb5cd36741350040fd28b432ceadf495be25b2
@@ -676,7 +676,7 @@ F test/boundary3.test 56ef82096b4329aca2be74fa1e2b0f762ea0eb45
 F test/boundary4.tcl 0bb4b1a94f4fc5ae59b79b9a2b7a140c405e2983
 F test/boundary4.test 89e02fa66397b8a325d5eb102b5806f961f8ec4b
 F test/btree01.test e08b3613540145b353f20c81cb18ead54ff12e0f
-F test/btree02.test fe69453d474d8154d19b904157ff1db4812fed99
+F test/btree02.test a0f33669ba76632247c14718af32db939fa6de5cd13890798ad3f2a362cf7fe4
 F test/btreefault.test c2bcb542685eea44621275cfedbd8a13f65201e3
 F test/busy.test 510dc6daaad18bcbbc085bcc6217d6dc418def5e73f72ce1475eea0cb7834727
 F test/cache.test 13bc046b26210471ca6f2889aceb1ea52dc717de
@@ -1754,7 +1754,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 8bc7f84c39f913b0b0f5e9f5fd9d7dd8bda8422248c069712b6992c32c759a83
+P 95db5bd9fea86a10c9528dd24841e1370dfdc0bbb5c98b7cbd808a8bc59dd48f a500893b6f64aced197cd32b79d51a481629a39d45dbcf0f02d65e5451ac4706
-R 6932e89db01172dd37443d3c6c0ba024
+R a895202b2ab9d783fc535831c38c174c
+T +closed a500893b6f64aced197cd32b79d51a481629a39d45dbcf0f02d65e5451ac4706
 U drh
-Z 944fd02700c6746ca58d0f2d1bfa9fb6
+Z 37d5cbe7046590064debd1c15a35aeb1

manifest.uuid

@@ -1 +1 @@
-95db5bd9fea86a10c9528dd24841e1370dfdc0bbb5c98b7cbd808a8bc59dd48f
+cdff3af7bedc5ebea04bd9b5e2112d3db451a475c18c9a9ebd45f6f3a89a43cb

src/build.c

@@ -225,7 +225,6 @@ void sqlite3FinishCoding(Parse *pParse){
   /* Get the VDBE program ready for execution
   */
   if( v && pParse->nErr==0 && !db->mallocFailed ){
-    assert( pParse->iCacheLevel==0 );  /* Disables and re-enables match */
     /* A minimum of one cursor is required if autoincrement is used
     *  See ticket [a696379c1f08866] */
     if( pParse->pAinc!=0 && pParse->nTab==0 ) pParse->nTab = 1;

src/delete.c

@@ -463,9 +463,8 @@ void sqlite3DeleteFrom(
       }
       iKey = iPk;
     }else{
-      iKey = pParse->nMem + 1;
+      iKey = ++pParse->nMem;
-      iKey = sqlite3ExprCodeGetColumn(pParse, pTab, -1, iTabCur, iKey, 0);
+      sqlite3ExprCodeGetColumnOfTable(v, pTab, iTabCur, -1, iKey);
-      if( iKey>pParse->nMem ) pParse->nMem = iKey;
     }
   
     if( eOnePass!=ONEPASS_OFF ){
@@ -898,7 +897,6 @@ int sqlite3GenerateIndexKey(
     if( pIdx->pPartIdxWhere ){
       *piPartIdxLabel = sqlite3VdbeMakeLabel(v);
       pParse->iSelfTab = iDataCur + 1;
-      sqlite3ExprCachePush(pParse);
       sqlite3ExprIfFalseDup(pParse, pIdx->pPartIdxWhere, *piPartIdxLabel, 
                             SQLITE_JUMPIFNULL);
       pParse->iSelfTab = 0;
@@ -945,6 +943,5 @@ int sqlite3GenerateIndexKey(
 void sqlite3ResolvePartIdxLabel(Parse *pParse, int iLabel){
   if( iLabel ){
     sqlite3VdbeResolveLabel(pParse->pVdbe, iLabel);
-    sqlite3ExprCachePop(pParse);
   }
 }

src/expr.c

@@ -581,7 +581,6 @@ static void codeVectorCompare(
     Expr *pL, *pR; 
     int r1, r2;
     assert( i>=0 && i<nLeft );
-    if( i>0 ) sqlite3ExprCachePush(pParse);
     r1 = exprVectorRegister(pParse, pLeft, i, regLeft, &pL, &regFree1);
     r2 = exprVectorRegister(pParse, pRight, i, regRight, &pR, &regFree2);
     codeCompare(pParse, pL, pR, opx, r1, r2, dest, p5);
@@ -593,7 +592,6 @@ static void codeVectorCompare(
     testcase(op==OP_Ne); VdbeCoverageIf(v,op==OP_Ne);
     sqlite3ReleaseTempReg(pParse, regFree1);
     sqlite3ReleaseTempReg(pParse, regFree2);
-    if( i>0 ) sqlite3ExprCachePop(pParse);
     if( i==nLeft-1 ){
       break;
     }
@@ -2627,7 +2625,6 @@ int sqlite3CodeSubselect(
   int rReg = 0;                           /* Register storing resulting */
   Vdbe *v = sqlite3GetVdbe(pParse);
   if( NEVER(v==0) ) return 0;
-  sqlite3ExprCachePush(pParse);
 
   /* The evaluation of the IN/EXISTS/SELECT must be repeated every time it
   ** is encountered if any of the following is true:
@@ -2763,7 +2760,6 @@ int sqlite3CodeSubselect(
               sqlite3VdbeAddOp3(v, OP_Insert, pExpr->iTable, r2, r3);
             }else{
               sqlite3VdbeAddOp4(v, OP_MakeRecord, r3, 1, r2, &affinity, 1);
-              sqlite3ExprCacheAffinityChange(pParse, r3, 1);
               sqlite3VdbeAddOp4Int(v, OP_IdxInsert, pExpr->iTable, r2, r3, 1);
             }
           }
@@ -2844,7 +2840,6 @@ int sqlite3CodeSubselect(
   if( jmpIfDynamic>=0 ){
     sqlite3VdbeJumpHere(v, jmpIfDynamic);
   }
-  sqlite3ExprCachePop(pParse);
 
   return rReg;
 }
@@ -2963,7 +2958,6 @@ static void sqlite3ExprCodeIN(
   ** aiMap[] array contains a mapping from the original LHS field order to
   ** the field order that matches the RHS index.
   */
-  sqlite3ExprCachePush(pParse);
   rLhsOrig = exprCodeVector(pParse, pLeft, &iDummy);
   for(i=0; i<nVector && aiMap[i]==i; i++){} /* Are LHS fields reordered? */
   if( i==nVector ){
@@ -3122,7 +3116,6 @@ static void sqlite3ExprCodeIN(
 
 sqlite3ExprCodeIN_finished:
   if( rLhs!=rLhsOrig ) sqlite3ReleaseTempReg(pParse, rLhs);
-  sqlite3ExprCachePop(pParse);
   VdbeComment((v, "end IN expr"));
 sqlite3ExprCodeIN_oom_error:
   sqlite3DbFree(pParse->db, aiMap);
@@ -3190,152 +3183,6 @@ static void codeInteger(Parse *pParse, Expr *pExpr, int negFlag, int iMem){
   }
 }
 
-/*
-** Erase column-cache entry number i
-*/
-static void cacheEntryClear(Parse *pParse, int i){
-  if( pParse->aColCache[i].tempReg ){
-    if( pParse->nTempReg<ArraySize(pParse->aTempReg) ){
-      pParse->aTempReg[pParse->nTempReg++] = pParse->aColCache[i].iReg;
-    }
-  }
-  pParse->nColCache--;
-  if( i<pParse->nColCache ){
-    pParse->aColCache[i] = pParse->aColCache[pParse->nColCache];
-  }
-}
-
-
-/*
-** Record in the column cache that a particular column from a
-** particular table is stored in a particular register.
-*/
-void sqlite3ExprCacheStore(Parse *pParse, int iTab, int iCol, int iReg){
-  int i;
-  int minLru;
-  int idxLru;
-  struct yColCache *p;
-
-  /* Unless an error has occurred, register numbers are always positive. */
-  assert( iReg>0 || pParse->nErr || pParse->db->mallocFailed );
-  assert( iCol>=-1 && iCol<32768 );  /* Finite column numbers */
-
-  /* The SQLITE_ColumnCache flag disables the column cache.  This is used
-  ** for testing only - to verify that SQLite always gets the same answer
-  ** with and without the column cache.
-  */
-  if( OptimizationDisabled(pParse->db, SQLITE_ColumnCache) ) return;
-
-  /* First replace any existing entry.
-  **
-  ** Actually, the way the column cache is currently used, we are guaranteed
-  ** that the object will never already be in cache.  Verify this guarantee.
-  */
-#ifndef NDEBUG
-  for(i=0, p=pParse->aColCache; i<pParse->nColCache; i++, p++){
-    assert( p->iTable!=iTab || p->iColumn!=iCol );
-  }
-#endif
-
-#ifdef SQLITE_DEBUG_COLUMNCACHE
-  /* Add a SetTabCol opcode for run-time verification that the column
-  ** cache is working correctly.
-  */
-  sqlite3VdbeAddOp3(pParse->pVdbe, OP_SetTabCol, iTab, iCol, iReg);
-#endif
-
-  /* If the cache is already full, delete the least recently used entry */
-  if( pParse->nColCache>=SQLITE_N_COLCACHE ){
-    minLru = 0x7fffffff;
-    idxLru = -1;
-    for(i=0, p=pParse->aColCache; i<SQLITE_N_COLCACHE; i++, p++){
-      if( p->lru<minLru ){
-        idxLru = i;
-        minLru = p->lru;
-      }
-    }
-    p = &pParse->aColCache[idxLru];
-  }else{
-    p = &pParse->aColCache[pParse->nColCache++];
-  }
-
-  /* Add the new entry to the end of the cache */
-  p->iLevel = pParse->iCacheLevel;
-  p->iTable = iTab;
-  p->iColumn = iCol;
-  p->iReg = iReg;
-  p->tempReg = 0;
-  p->lru = pParse->iCacheCnt++;
-}
-
-/*
-** Indicate that registers between iReg..iReg+nReg-1 are being overwritten.
-** Purge the range of registers from the column cache.
-*/
-void sqlite3ExprCacheRemove(Parse *pParse, int iReg, int nReg){
-  int i = 0;
-  while( i<pParse->nColCache ){
-    struct yColCache *p = &pParse->aColCache[i];
-    if( p->iReg >= iReg && p->iReg < iReg+nReg ){
-      cacheEntryClear(pParse, i);
-    }else{
-      i++;
-    }
-  }
-}
-
-/*
-** Remember the current column cache context.  Any new entries added
-** added to the column cache after this call are removed when the
-** corresponding pop occurs.
-*/
-void sqlite3ExprCachePush(Parse *pParse){
-  pParse->iCacheLevel++;
-#ifdef SQLITE_DEBUG
-  if( pParse->db->flags & SQLITE_VdbeAddopTrace ){
-    printf("PUSH to %d\n", pParse->iCacheLevel);
-  }
-#endif
-}
-
-/*
-** Remove from the column cache any entries that were added since the
-** the previous sqlite3ExprCachePush operation.  In other words, restore
-** the cache to the state it was in prior the most recent Push.
-*/
-void sqlite3ExprCachePop(Parse *pParse){
-  int i = 0;
-  assert( pParse->iCacheLevel>=1 );
-  pParse->iCacheLevel--;
-#ifdef SQLITE_DEBUG
-  if( pParse->db->flags & SQLITE_VdbeAddopTrace ){
-    printf("POP  to %d\n", pParse->iCacheLevel);
-  }
-#endif
-  while( i<pParse->nColCache ){
-    if( pParse->aColCache[i].iLevel>pParse->iCacheLevel ){
-      cacheEntryClear(pParse, i);
-    }else{
-      i++;
-    }
-  }
-}
-
-/*
-** When a cached column is reused, make sure that its register is
-** no longer available as a temp register.  ticket #3879:  that same
-** register might be in the cache in multiple places, so be sure to
-** get them all.
-*/
-static void sqlite3ExprCachePinRegister(Parse *pParse, int iReg){
-  int i;
-  struct yColCache *p;
-  for(i=0, p=pParse->aColCache; i<pParse->nColCache; i++, p++){
-    if( p->iReg==iReg ){
-      p->tempReg = 0;
-    }
-  }
-}
 
 /* Generate code that will load into register regOut a value that is
 ** appropriate for the iIdxCol-th column of index pIdx.
@@ -3391,12 +3238,7 @@ void sqlite3ExprCodeGetColumnOfTable(
 
 /*
 ** Generate code that will extract the iColumn-th column from
-** table pTab and store the column value in a register. 
+** table pTab and store the column value in register iReg. 
-**
-** An effort is made to store the column value in register iReg.  This
-** is not garanteeed for GetColumn() - the result can be stored in
-** any register.  But the result is guaranteed to land in register iReg
-** for GetColumnToReg().
 **
 ** There must be an open cursor to pTab in iTable when this routine
 ** is called.  If iColumn<0 then code is generated that extracts the rowid.
@@ -3410,99 +3252,23 @@ int sqlite3ExprCodeGetColumn(
   u8 p5            /* P5 value for OP_Column + FLAGS */
 ){
   Vdbe *v = pParse->pVdbe;
-  int i;
-  struct yColCache *p;
-
-  for(i=0, p=pParse->aColCache; i<pParse->nColCache; i++, p++){
-    if( p->iTable==iTable && p->iColumn==iColumn ){
-      p->lru = pParse->iCacheCnt++;
-      sqlite3ExprCachePinRegister(pParse, p->iReg);
-#ifdef SQLITE_DEBUG_COLUMNCACHE
-      sqlite3VdbeAddOp3(v, OP_VerifyTabCol, iTable, iColumn, p->iReg);
-#endif
-      return p->iReg;
-    }
-  }  
   assert( v!=0 );
   sqlite3ExprCodeGetColumnOfTable(v, pTab, iTable, iColumn, iReg);
   if( p5 ){
     sqlite3VdbeChangeP5(v, p5);
-  }else{   
-    sqlite3ExprCacheStore(pParse, iTable, iColumn, iReg);
   }
   return iReg;
 }
-void sqlite3ExprCodeGetColumnToReg(
-  Parse *pParse,   /* Parsing and code generating context */
-  Table *pTab,     /* Description of the table we are reading from */
-  int iColumn,     /* Index of the table column */
-  int iTable,      /* The cursor pointing to the table */
-  int iReg         /* Store results here */
-){
-  int r1 = sqlite3ExprCodeGetColumn(pParse, pTab, iColumn, iTable, iReg, 0);
-  if( r1!=iReg ) sqlite3VdbeAddOp2(pParse->pVdbe, OP_SCopy, r1, iReg);
-}
-
-
-/*
-** Clear all column cache entries.
-*/
-void sqlite3ExprCacheClear(Parse *pParse){
-  int i;
-
-#ifdef SQLITE_DEBUG
-  if( pParse->db->flags & SQLITE_VdbeAddopTrace ){
-    printf("CLEAR\n");
-  }
-#endif
-  for(i=0; i<pParse->nColCache; i++){
-    if( pParse->aColCache[i].tempReg
-     && pParse->nTempReg<ArraySize(pParse->aTempReg)
-    ){
-       pParse->aTempReg[pParse->nTempReg++] = pParse->aColCache[i].iReg;
-    }
-  }
-  pParse->nColCache = 0;
-}
-
-/*
-** Record the fact that an affinity change has occurred on iCount
-** registers starting with iStart.
-*/
-void sqlite3ExprCacheAffinityChange(Parse *pParse, int iStart, int iCount){
-  sqlite3ExprCacheRemove(pParse, iStart, iCount);
-}
 
 /*
 ** Generate code to move content from registers iFrom...iFrom+nReg-1
-** over to iTo..iTo+nReg-1. Keep the column cache up-to-date.
+** over to iTo..iTo+nReg-1.
 */
 void sqlite3ExprCodeMove(Parse *pParse, int iFrom, int iTo, int nReg){
   assert( iFrom>=iTo+nReg || iFrom+nReg<=iTo );
   sqlite3VdbeAddOp3(pParse->pVdbe, OP_Move, iFrom, iTo, nReg);
-  sqlite3ExprCacheRemove(pParse, iFrom, nReg);
 }
 
-#if defined(SQLITE_DEBUG) || defined(SQLITE_COVERAGE_TEST)
-/*
-** Return true if any register in the range iFrom..iTo (inclusive)
-** is used as part of the column cache.
-**
-** This routine is used within assert() and testcase() macros only
-** and does not appear in a normal build.
-*/
-static int usedAsColumnCache(Parse *pParse, int iFrom, int iTo){
-  int i;
-  struct yColCache *p;
-  for(i=0, p=pParse->aColCache; i<pParse->nColCache; i++, p++){
-    int r = p->iReg;
-    if( r>=iFrom && r<=iTo ) return 1;    /*NO_TEST*/
-  }
-  return 0;
-}
-#endif /* SQLITE_DEBUG || SQLITE_COVERAGE_TEST */
-
-
 /*
 ** Convert a scalar expression node to a TK_REGISTER referencing
 ** register iReg.  The caller must ensure that iReg already contains
@@ -3683,8 +3449,6 @@ expr_code_doover:
       }
       sqlite3VdbeAddOp2(v, OP_Cast, target,
                         sqlite3AffinityType(pExpr->u.zToken, 0));
-      testcase( usedAsColumnCache(pParse, inReg, inReg) );
-      sqlite3ExprCacheAffinityChange(pParse, inReg, 1);
       return inReg;
     }
 #endif /* SQLITE_OMIT_CAST */
@@ -3870,10 +3634,7 @@ expr_code_doover:
         for(i=1; i<nFarg; i++){
           sqlite3VdbeAddOp2(v, OP_NotNull, target, endCoalesce);
           VdbeCoverage(v);
-          sqlite3ExprCacheRemove(pParse, target, 1);
-          sqlite3ExprCachePush(pParse);
           sqlite3ExprCode(pParse, pFarg->a[i].pExpr, target);
-          sqlite3ExprCachePop(pParse);
         }
         sqlite3VdbeResolveLabel(v, endCoalesce);
         break;
@@ -3939,10 +3700,8 @@ expr_code_doover:
           }
         }
 
-        sqlite3ExprCachePush(pParse);     /* Ticket 2ea2425d34be */
         sqlite3ExprCodeExprList(pParse, pFarg, r1, 0,
                                 SQLITE_ECEL_DUP|SQLITE_ECEL_FACTOR);
-        sqlite3ExprCachePop(pParse);      /* Ticket 2ea2425d34be */
       }else{
         r1 = 0;
       }
@@ -4115,9 +3874,7 @@ expr_code_doover:
     case TK_IF_NULL_ROW: {
       int addrINR;
       addrINR = sqlite3VdbeAddOp1(v, OP_IfNullRow, pExpr->iTable);
-      sqlite3ExprCachePush(pParse);
       inReg = sqlite3ExprCodeTarget(pParse, pExpr->pLeft, target);
-      sqlite3ExprCachePop(pParse);
       sqlite3VdbeJumpHere(v, addrINR);
       sqlite3VdbeChangeP3(v, addrINR, inReg);
       break;
@@ -4154,7 +3911,6 @@ expr_code_doover:
       Expr opCompare;                   /* The X==Ei expression */
       Expr *pX;                         /* The X expression */
       Expr *pTest = 0;                  /* X==Ei (form A) or just Ei (form B) */
-      VVA_ONLY( int iCacheLevel = pParse->iCacheLevel; )
 
       assert( !ExprHasProperty(pExpr, EP_xIsSelect) && pExpr->x.pList );
       assert(pExpr->x.pList->nExpr > 0);
@@ -4178,7 +3934,6 @@ expr_code_doover:
         regFree1 = 0;
       }
       for(i=0; i<nExpr-1; i=i+2){
-        sqlite3ExprCachePush(pParse);
         if( pX ){
           assert( pTest!=0 );
           opCompare.pRight = aListelem[i].pExpr;
@@ -4191,18 +3946,13 @@ expr_code_doover:
         testcase( aListelem[i+1].pExpr->op==TK_COLUMN );
         sqlite3ExprCode(pParse, aListelem[i+1].pExpr, target);
         sqlite3VdbeGoto(v, endLabel);
-        sqlite3ExprCachePop(pParse);
         sqlite3VdbeResolveLabel(v, nextCase);
       }
       if( (nExpr&1)!=0 ){
-        sqlite3ExprCachePush(pParse);
         sqlite3ExprCode(pParse, pEList->a[nExpr-1].pExpr, target);
-        sqlite3ExprCachePop(pParse);
       }else{
         sqlite3VdbeAddOp2(v, OP_Null, 0, target);
       }
-      assert( pParse->db->mallocFailed || pParse->nErr>0 
-           || pParse->iCacheLevel==iCacheLevel );
       sqlite3VdbeResolveLabel(v, endLabel);
       break;
     }
@@ -4562,18 +4312,14 @@ void sqlite3ExprIfTrue(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
       int d2 = sqlite3VdbeMakeLabel(v);
       testcase( jumpIfNull==0 );
       sqlite3ExprIfFalse(pParse, pExpr->pLeft, d2,jumpIfNull^SQLITE_JUMPIFNULL);
-      sqlite3ExprCachePush(pParse);
       sqlite3ExprIfTrue(pParse, pExpr->pRight, dest, jumpIfNull);
       sqlite3VdbeResolveLabel(v, d2);
-      sqlite3ExprCachePop(pParse);
       break;
     }
     case TK_OR: {
       testcase( jumpIfNull==0 );
       sqlite3ExprIfTrue(pParse, pExpr->pLeft, dest, jumpIfNull);
-      sqlite3ExprCachePush(pParse);
       sqlite3ExprIfTrue(pParse, pExpr->pRight, dest, jumpIfNull);
-      sqlite3ExprCachePop(pParse);
       break;
     }
     case TK_NOT: {
@@ -4732,19 +4478,15 @@ void sqlite3ExprIfFalse(Parse *pParse, Expr *pExpr, int dest, int jumpIfNull){
     case TK_AND: {
       testcase( jumpIfNull==0 );
       sqlite3ExprIfFalse(pParse, pExpr->pLeft, dest, jumpIfNull);
-      sqlite3ExprCachePush(pParse);
       sqlite3ExprIfFalse(pParse, pExpr->pRight, dest, jumpIfNull);
-      sqlite3ExprCachePop(pParse);
       break;
     }
     case TK_OR: {
       int d2 = sqlite3VdbeMakeLabel(v);
       testcase( jumpIfNull==0 );
       sqlite3ExprIfTrue(pParse, pExpr->pLeft, d2, jumpIfNull^SQLITE_JUMPIFNULL);
-      sqlite3ExprCachePush(pParse);
       sqlite3ExprIfFalse(pParse, pExpr->pRight, dest, jumpIfNull);
       sqlite3VdbeResolveLabel(v, d2);
-      sqlite3ExprCachePop(pParse);
       break;
     }
     case TK_NOT: {
@@ -5512,21 +5254,9 @@ int sqlite3GetTempReg(Parse *pParse){
 /*
 ** Deallocate a register, making available for reuse for some other
 ** purpose.
-**
-** If a register is currently being used by the column cache, then
-** the deallocation is deferred until the column cache line that uses
-** the register becomes stale.
 */
 void sqlite3ReleaseTempReg(Parse *pParse, int iReg){
   if( iReg && pParse->nTempReg<ArraySize(pParse->aTempReg) ){
-    int i;
-    struct yColCache *p;
-    for(i=0, p=pParse->aColCache; i<pParse->nColCache; i++, p++){
-      if( p->iReg==iReg ){
-        p->tempReg = 1;
-        return;
-      }
-    }
     pParse->aTempReg[pParse->nTempReg++] = iReg;
   }
 }
@@ -5540,7 +5270,6 @@ int sqlite3GetTempRange(Parse *pParse, int nReg){
   i = pParse->iRangeReg;
   n = pParse->nRangeReg;
   if( nReg<=n ){
-    assert( !usedAsColumnCache(pParse, i, i+n-1) );
     pParse->iRangeReg += nReg;
     pParse->nRangeReg -= nReg;
   }else{
@@ -5554,7 +5283,6 @@ void sqlite3ReleaseTempRange(Parse *pParse, int iReg, int nReg){
     sqlite3ReleaseTempReg(pParse, iReg);
     return;
   }
-  sqlite3ExprCacheRemove(pParse, iReg, nReg);
   if( nReg>pParse->nRangeReg ){
     pParse->nRangeReg = nReg;
     pParse->iRangeReg = iReg;

src/insert.c

@@ -1533,7 +1533,6 @@ void sqlite3GenerateConstraintChecks(
     sqlite3VdbeVerifyAbortable(v, onError);
     sqlite3VdbeAddOp3(v, OP_NotExists, iDataCur, addrRowidOk, regNewData);
     VdbeCoverage(v);
-    sqlite3ExprCachePush(pParse);
 
     switch( onError ){
       default: {
@@ -1610,7 +1609,6 @@ void sqlite3GenerateConstraintChecks(
         break;
       }
     }
-    sqlite3ExprCachePop(pParse);
     sqlite3VdbeResolveLabel(v, addrRowidOk);
     if( sAddr.ipkTop ){
       sAddr.ipkBtm = sqlite3VdbeAddOp0(v, OP_Goto);
@@ -1744,7 +1742,6 @@ void sqlite3GenerateConstraintChecks(
     }
 
     /* Check to see if the new index entry will be unique */
-    sqlite3ExprCachePush(pParse);
     sqlite3VdbeVerifyAbortable(v, onError);
     sqlite3VdbeAddOp4Int(v, OP_NoConflict, iThisCur, addrUniqueOk,
                          regIdx, pIdx->nKeyCol); VdbeCoverage(v);
@@ -1850,7 +1847,6 @@ void sqlite3GenerateConstraintChecks(
     }else{
       sqlite3VdbeResolveLabel(v, addrUniqueOk);
     }
-    sqlite3ExprCachePop(pParse);
     if( regR!=regIdx ) sqlite3ReleaseTempRange(pParse, regR, nPkField);
 
   }
@@ -1954,7 +1950,6 @@ void sqlite3CompleteInsertion(
   sqlite3SetMakeRecordP5(v, pTab);
   if( !bAffinityDone ){
     sqlite3TableAffinity(v, pTab, 0);
-    sqlite3ExprCacheAffinityChange(pParse, regData, pTab->nCol);
   }
   if( pParse->nested ){
     pik_flags = 0;

src/pragma.c

@@ -1550,7 +1550,6 @@ void sqlite3Pragma(
 
         if( pTab->tnum<1 ) continue;  /* Skip VIEWs or VIRTUAL TABLEs */
         pPk = HasRowid(pTab) ? 0 : sqlite3PrimaryKeyIndex(pTab);
-        sqlite3ExprCacheClear(pParse);
         sqlite3OpenTableAndIndices(pParse, pTab, OP_OpenRead, 0,
                                    1, 0, &iDataCur, &iIdxCur);
         /* reg[7] counts the number of entries in the table.
@@ -1593,7 +1592,6 @@ void sqlite3Pragma(
             char *zErr;
             int k;
             pParse->iSelfTab = iDataCur + 1;
-            sqlite3ExprCachePush(pParse);
             for(k=pCheck->nExpr-1; k>0; k--){
               sqlite3ExprIfFalse(pParse, pCheck->a[k].pExpr, addrCkFault, 0);
             }
@@ -1606,7 +1604,6 @@ void sqlite3Pragma(
             sqlite3VdbeAddOp4(v, OP_String8, 0, 3, 0, zErr, P4_DYNAMIC);
             integrityCheckResultRow(v);
             sqlite3VdbeResolveLabel(v, addrCkOk);
-            sqlite3ExprCachePop(pParse);
           }
           sqlite3ExprListDelete(db, pCheck);
         }

src/select.c

@@ -1149,7 +1149,6 @@ static void selectInnerLoop(
         assert( sqlite3Strlen30(pDest->zAffSdst)==nResultCol );
         sqlite3VdbeAddOp4(v, OP_MakeRecord, regResult, nResultCol, 
             r1, pDest->zAffSdst, nResultCol);
-        sqlite3ExprCacheAffinityChange(pParse, regResult, nResultCol);
         sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iParm, r1, regResult, nResultCol);
         sqlite3ReleaseTempReg(pParse, r1);
       }
@@ -1193,7 +1192,6 @@ static void selectInnerLoop(
         sqlite3VdbeAddOp1(v, OP_Yield, pDest->iSDParm);
       }else{
         sqlite3VdbeAddOp2(v, OP_ResultRow, regResult, nResultCol);
-        sqlite3ExprCacheAffinityChange(pParse, regResult, nResultCol);
       }
       break;
     }
@@ -1550,7 +1548,6 @@ static void generateSortTail(
       assert( nColumn==sqlite3Strlen30(pDest->zAffSdst) );
       sqlite3VdbeAddOp4(v, OP_MakeRecord, regRow, nColumn, regRowid,
                         pDest->zAffSdst, nColumn);
-      sqlite3ExprCacheAffinityChange(pParse, regRow, nColumn);
       sqlite3VdbeAddOp4Int(v, OP_IdxInsert, iParm, regRowid, regRow, nColumn);
       break;
     }
@@ -1565,7 +1562,6 @@ static void generateSortTail(
       testcase( eDest==SRT_Coroutine );
       if( eDest==SRT_Output ){
         sqlite3VdbeAddOp2(v, OP_ResultRow, pDest->iSdst, nColumn);
-        sqlite3ExprCacheAffinityChange(pParse, pDest->iSdst, nColumn);
       }else{
         sqlite3VdbeAddOp1(v, OP_Yield, pDest->iSDParm);
       }
@@ -2166,7 +2162,6 @@ static void computeLimitRegisters(Parse *pParse, Select *p, int iBreak){
   ** The current implementation interprets "LIMIT 0" to mean
   ** no rows.
   */
-  sqlite3ExprCacheClear(pParse);
   if( pLimit ){
     assert( pLimit->op==TK_LIMIT );
     assert( pLimit->pLeft!=0 );
@@ -2952,7 +2947,6 @@ static int generateOutputSubroutine(
       r1 = sqlite3GetTempReg(pParse);
       sqlite3VdbeAddOp4(v, OP_MakeRecord, pIn->iSdst, pIn->nSdst, 
           r1, pDest->zAffSdst, pIn->nSdst);
-      sqlite3ExprCacheAffinityChange(pParse, pIn->iSdst, pIn->nSdst);
       sqlite3VdbeAddOp4Int(v, OP_IdxInsert, pDest->iSDParm, r1,
                            pIn->iSdst, pIn->nSdst);
       sqlite3ReleaseTempReg(pParse, r1);
@@ -2995,7 +2989,6 @@ static int generateOutputSubroutine(
     default: {
       assert( pDest->eDest==SRT_Output );
       sqlite3VdbeAddOp2(v, OP_ResultRow, pIn->iSdst, pIn->nSdst);
-      sqlite3ExprCacheAffinityChange(pParse, pIn->iSdst, pIn->nSdst);
       break;
     }
   }
@@ -5336,36 +5329,21 @@ static void updateAccumulator(Parse *pParse, int regAcc, AggInfo *pAggInfo){
     sqlite3VdbeAddOp3(v, OP_AggStep, 0, regAgg, pF->iMem);
     sqlite3VdbeAppendP4(v, pF->pFunc, P4_FUNCDEF);
     sqlite3VdbeChangeP5(v, (u8)nArg);
-    sqlite3ExprCacheAffinityChange(pParse, regAgg, nArg);
     sqlite3ReleaseTempRange(pParse, regAgg, nArg);
     if( addrNext ){
       sqlite3VdbeResolveLabel(v, addrNext);
-      sqlite3ExprCacheClear(pParse);
     }
   }
-
-  /* Before populating the accumulator registers, clear the column cache.
-  ** Otherwise, if any of the required column values are already present 
-  ** in registers, sqlite3ExprCode() may use OP_SCopy to copy the value
-  ** to pC->iMem. But by the time the value is used, the original register
-  ** may have been used, invalidating the underlying buffer holding the
-  ** text or blob value. See ticket [883034dcb5].
-  **
-  ** Another solution would be to change the OP_SCopy used to copy cached
-  ** values to an OP_Copy.
-  */
   if( regHit==0 && pAggInfo->nAccumulator ){
     regHit = regAcc;
   }
   if( regHit ){
     addrHitTest = sqlite3VdbeAddOp1(v, OP_If, regHit); VdbeCoverage(v);
   }
-  sqlite3ExprCacheClear(pParse);
   for(i=0, pC=pAggInfo->aCol; i<pAggInfo->nAccumulator; i++, pC++){
     sqlite3ExprCode(pParse, pC->pExpr, pC->iMem);
   }
   pAggInfo->directMode = 0;
-  sqlite3ExprCacheClear(pParse);
   if( addrHitTest ){
     sqlite3VdbeJumpHere(v, addrHitTest);
   }
@@ -6318,15 +6296,14 @@ int sqlite3Select(
           }
         }
         regBase = sqlite3GetTempRange(pParse, nCol);
-        sqlite3ExprCacheClear(pParse);
         sqlite3ExprCodeExprList(pParse, pGroupBy, regBase, 0, 0);
         j = nGroupBy;
         for(i=0; i<sAggInfo.nColumn; i++){
           struct AggInfo_col *pCol = &sAggInfo.aCol[i];
           if( pCol->iSorterColumn>=j ){
             int r1 = j + regBase;
-            sqlite3ExprCodeGetColumnToReg(pParse, 
+            sqlite3ExprCodeGetColumnOfTable(v,
-                               pCol->pTab, pCol->iColumn, pCol->iTable, r1);
+                               pCol->pTab, pCol->iTable, pCol->iColumn, r1);
             j++;
           }
         }
@@ -6342,8 +6319,6 @@ int sqlite3Select(
         sqlite3VdbeAddOp2(v, OP_SorterSort, sAggInfo.sortingIdx, addrEnd);
         VdbeComment((v, "GROUP BY sort")); VdbeCoverage(v);
         sAggInfo.useSortingIdx = 1;
-        sqlite3ExprCacheClear(pParse);
-
       }
 
       /* If the index or temporary table used by the GROUP BY sort
@@ -6366,7 +6341,6 @@ int sqlite3Select(
       ** from the previous row currently stored in a0, a1, a2...
       */
       addrTopOfLoop = sqlite3VdbeCurrentAddr(v);
-      sqlite3ExprCacheClear(pParse);
       if( groupBySort ){
         sqlite3VdbeAddOp3(v, OP_SorterData, sAggInfo.sortingIdx,
                           sortOut, sortPTab);

src/sqliteInt.h

@@ -367,17 +367,6 @@
 # undef NDEBUG
 #endif
 
-/* SQLITE_DEBUG_COLUMNCACHE is synomous with SQLITE_DEBUG.  The 
-** SQLITE_DEBUG_COLUMNCACHE symbol only exists to provide a convenient
-** way to search for all code that deals with verifying correct behavior
-** of the column cache.
-*/
-#ifdef SQLITE_DEBUG
-# define SQLITE_DEBUG_COLUMNCACHE 1
-#else
-# undef SQLIT_DEBUG_COLUMNCACHE
-#endif
-
 /*
 ** Enable SQLITE_ENABLE_EXPLAIN_COMMENTS if SQLITE_DEBUG is turned on.
 */
@@ -1569,7 +1558,7 @@ struct sqlite3 {
 ** selectively disable various optimizations.
 */
 #define SQLITE_QueryFlattener 0x0001   /* Query flattening */
-#define SQLITE_ColumnCache    0x0002   /* Column cache */
+                          /*  0x0002   available for reuse */
 #define SQLITE_GroupByOrder   0x0004   /* GROUPBY cover of ORDERBY */
 #define SQLITE_FactorOutConst 0x0008   /* Constant factoring */
 #define SQLITE_DistinctOpt    0x0010   /* DISTINCT using indexes */
@@ -2968,13 +2957,6 @@ struct AutoincInfo {
   int regCtr;           /* Memory register holding the rowid counter */
 };
 
-/*
-** Size of the column cache
-*/
-#ifndef SQLITE_N_COLCACHE
-# define SQLITE_N_COLCACHE 10
-#endif
-
 /*
 ** At least one instance of the following structure is created for each
 ** trigger that may be fired while parsing an INSERT, UPDATE or DELETE
@@ -3050,7 +3032,6 @@ struct Parse {
   u8 hasCompound;      /* Need to invoke convertCompoundSelectToSubquery() */
   u8 okConstFactor;    /* OK to factor out constants */
   u8 disableLookaside; /* Number of times lookaside has been disabled */
-  u8 nColCache;        /* Number of entries in aColCache[] */
   int nRangeReg;       /* Size of the temporary register block */
   int iRangeReg;       /* First register in temporary register block */
   int nErr;            /* Number of errors seen */
@@ -3060,8 +3041,6 @@ struct Parse {
   int szOpAlloc;       /* Bytes of memory space allocated for Vdbe.aOp[] */
   int iSelfTab;        /* Table associated with an index on expr, or negative
                        ** of the base register during check-constraint eval */
-  int iCacheLevel;     /* ColCache valid when aColCache[].iLevel<=iCacheLevel */
-  int iCacheCnt;       /* Counter used to generate aColCache[].lru values */
   int nLabel;          /* Number of labels used */
   int *aLabel;         /* Space to hold the labels */
   ExprList *pConstExpr;/* Constant expressions */
@@ -3091,17 +3070,9 @@ struct Parse {
   ** Fields above must be initialized to zero.  The fields that follow,
   ** down to the beginning of the recursive section, do not need to be
   ** initialized as they will be set before being used.  The boundary is
-  ** determined by offsetof(Parse,aColCache).
+  ** determined by offsetof(Parse,aTempReg).
   **************************************************************************/
 
-  struct yColCache {
-    int iTable;           /* Table cursor number */
-    i16 iColumn;          /* Table column number */
-    u8 tempReg;           /* iReg is a temp register that needs to be freed */
-    int iLevel;           /* Nesting level */
-    int iReg;             /* Reg with value of this column. 0 means none. */
-    int lru;              /* Least recently used entry has the smallest value */
-  } aColCache[SQLITE_N_COLCACHE];  /* One for each column cache entry */
   int aTempReg[8];        /* Holding area for temporary registers */
   Token sNameToken;       /* Token with unqualified schema object name */
 
@@ -3143,7 +3114,7 @@ struct Parse {
 /*
 ** Sizes and pointers of various parts of the Parse object.
 */
-#define PARSE_HDR_SZ offsetof(Parse,aColCache) /* Recursive part w/o aColCache*/
+#define PARSE_HDR_SZ offsetof(Parse,aTempReg) /* Recursive part w/o aColCache*/
 #define PARSE_RECURSE_SZ offsetof(Parse,sLastToken)    /* Recursive part */
 #define PARSE_TAIL_SZ (sizeof(Parse)-PARSE_RECURSE_SZ) /* Non-recursive part */
 #define PARSE_TAIL(X) (((char*)(X))+PARSE_RECURSE_SZ)  /* Pointer to tail */
@@ -3927,15 +3898,8 @@ int sqlite3WhereOkOnePass(WhereInfo*, int*);
 #define ONEPASS_MULTI    2        /* ONEPASS is valid for multiple rows */
 void sqlite3ExprCodeLoadIndexColumn(Parse*, Index*, int, int, int);
 int sqlite3ExprCodeGetColumn(Parse*, Table*, int, int, int, u8);
-void sqlite3ExprCodeGetColumnToReg(Parse*, Table*, int, int, int);
 void sqlite3ExprCodeGetColumnOfTable(Vdbe*, Table*, int, int, int);
 void sqlite3ExprCodeMove(Parse*, int, int, int);
-void sqlite3ExprCacheStore(Parse*, int, int, int);
-void sqlite3ExprCachePush(Parse*);
-void sqlite3ExprCachePop(Parse*);
-void sqlite3ExprCacheRemove(Parse*, int, int);
-void sqlite3ExprCacheClear(Parse*);
-void sqlite3ExprCacheAffinityChange(Parse*, int, int);
 void sqlite3ExprCode(Parse*, Expr*, int);
 void sqlite3ExprCodeCopy(Parse*, Expr*, int);
 void sqlite3ExprCodeFactorable(Parse*, Expr*, int);

src/test1.c

@@ -6982,7 +6982,6 @@ static int SQLITE_TCLAPI optimization_control(
     { "all",                 SQLITE_AllOpts        },
     { "none",                0                     },
     { "query-flattener",     SQLITE_QueryFlattener },
-    { "column-cache",        SQLITE_ColumnCache    },
     { "groupby-order",       SQLITE_GroupByOrder   },
     { "factor-constants",    SQLITE_FactorOutConst },
     { "distinct-opt",        SQLITE_DistinctOpt    },

src/update.c

@@ -610,13 +610,7 @@ void sqlite3Update(
         */
         testcase( i==31 );
         testcase( i==32 );
-        sqlite3ExprCodeGetColumnToReg(pParse, pTab, i, iDataCur, regNew+i);
+        sqlite3ExprCodeGetColumnOfTable(v, pTab, iDataCur, i, regNew+i);
-        if( tmask & TRIGGER_BEFORE ){
-          /* This value will be recomputed in After-BEFORE-trigger-reload-loop
-          ** below, so make sure that it is not cached and reused.
-          ** Ticket d85fffd6ffe856092ed8daefa811b1e399706b28. */
-          sqlite3ExprCacheRemove(pParse, regNew+i, 1);
-        }
       }else{
         sqlite3VdbeAddOp2(v, OP_Null, 0, regNew+i);
       }

src/vdbe.c

@@ -36,18 +36,6 @@
 # define memAboutToChange(P,M)
 #endif
 
-/*
-** Given a cursor number and a column for a table or index, compute a
-** hash value for use in the Mem.iTabColHash value.  The iTabColHash
-** column is only used for verification - it is omitted from production
-** builds.  Collisions are harmless in the sense that the correct answer
-** still results.  The only harm of collisions is that they can potential
-** reduce column-cache error detection during SQLITE_DEBUG builds.
-**
-** No valid hash should be 0.
-*/
-#define TableColumnHash(T,C)  (((u32)(T)<<16)^(u32)(C+2))
-
 /*
 ** The following global variable is incremented every time a cursor
 ** moves, either by the OP_SeekXX, OP_Next, or OP_Prev opcodes.  The test
@@ -1308,7 +1296,6 @@ case OP_Copy: {
     Deephemeralize(pOut);
 #ifdef SQLITE_DEBUG
     pOut->pScopyFrom = 0;
-    pOut->iTabColHash = 0;
 #endif
     REGISTER_TRACE(pOp->p2+pOp->p3-n, pOut);
     if( (n--)==0 ) break;
@@ -1925,6 +1912,11 @@ case OP_Ge: {             /* same as TK_GE, jump, in1, in3 */
   u16 flags1;         /* Copy of initial value of pIn1->flags */
   u16 flags3;         /* Copy of initial value of pIn3->flags */
 
+  /* The only way for P1 and P3 to be the same is when comparing constants.
+  ** But in that case, the affinities will always be SQLITE_AFF_BLOB or none */
+  assert( pOp->p1!=pOp->p3 || (pOp->p5 & SQLITE_AFF_MASK)<=SQLITE_AFF_BLOB );
+  testcase( pOp->p1==pOp->p3 );
+
   pIn1 = &aMem[pOp->p1];
   pIn3 = &aMem[pOp->p3];
   flags1 = pIn1->flags;
@@ -1972,7 +1964,11 @@ case OP_Ge: {             /* same as TK_GE, jump, in1, in3 */
       if( (flags1 | flags3)&MEM_Str ){
         if( (flags1 & (MEM_Int|MEM_Real|MEM_Str))==MEM_Str ){
           applyNumericAffinity(pIn1,0);
-          testcase( flags3!=pIn3->flags ); /* Possible if pIn1==pIn3 */
+          /* testcase( flags3!=pIn3->flags );
+          ** this used to be possible with pIn1==pIn3, but not since
+          ** the column cache was removed.  The following assignment
+          ** is essentially a no-op.  But, it prevents defense-in-depth
+          ** in case our analysis is incorrect, so it is left in. */
           flags3 = pIn3->flags;
         }
         if( (flags3 & (MEM_Int|MEM_Real|MEM_Str))==MEM_Str ){
@@ -7446,34 +7442,6 @@ case OP_Abortable: {
 }
 #endif
 
-#ifdef SQLITE_DEBUG_COLUMNCACHE
-/* Opcode:  SetTabCol   P1 P2 P3 * *
-**
-** Set a flag in register REG[P3] indicating that it holds the value
-** of column P2 from the table on cursor P1.  This flag is checked
-** by a subsequent VerifyTabCol opcode.
-**
-** This opcode only appears SQLITE_DEBUG builds.  It is used to verify
-** that the expression table column cache is working correctly.
-*/
-case OP_SetTabCol: {
-  aMem[pOp->p3].iTabColHash = TableColumnHash(pOp->p1,pOp->p2);
-  break;
-}
-/* Opcode:  VerifyTabCol   P1 P2 P3 * *
-**
-** Verify that register REG[P3] contains the value of column P2 from
-** cursor P1.  Assert() if this is not the case.
-**
-** This opcode only appears SQLITE_DEBUG builds.  It is used to verify
-** that the expression table column cache is working correctly.
-*/
-case OP_VerifyTabCol: {
-  assert( aMem[pOp->p3].iTabColHash == TableColumnHash(pOp->p1,pOp->p2) );
-  break;
-}
-#endif
-
 /* Opcode: Noop * * * * *
 **
 ** Do nothing.  This instruction is often useful as a jump

src/vdbeInt.h

@@ -211,10 +211,6 @@ struct sqlite3_value {
   Mem *pScopyFrom;    /* This Mem is a shallow copy of pScopyFrom */
   u16 mScopyFlags;    /* flags value immediately after the shallow copy */
 #endif
-#ifdef SQLITE_DEBUG_COLUMNCACHE
-  u32 iTabColHash;    /* Hash of table.column that is origin of this value */
-  u32 iPadding;       /* sqlite3_value objects must be 8-byte aligned */
-#endif
 };
 
 /*

src/vdbeapi.c

@@ -971,9 +971,6 @@ static const Mem *columnNullValue(void){
 #ifdef SQLITE_DEBUG
         /* .pScopyFrom = */ (Mem*)0,
         /* .mScopyFlags= */ 0,
-#endif
-#ifdef SQLITE_DEBUG_COLUMNCACHE
-        /* .iTabColHash= */ 0,
 #endif
       };
   return &nullMem;

src/vdbeaux.c

@@ -193,14 +193,6 @@ int sqlite3VdbeAddOp3(Vdbe *p, int op, int p1, int p2, int p3){
 #endif
 #ifdef SQLITE_DEBUG
   if( p->db->flags & SQLITE_VdbeAddopTrace ){
-    int jj, kk;
-    Parse *pParse = p->pParse;
-    for(jj=kk=0; jj<pParse->nColCache; jj++){
-      struct yColCache *x = pParse->aColCache + jj;
-      printf(" r[%d]={%d:%d}", x->iReg, x->iTable, x->iColumn);
-      kk++;
-    }
-    if( kk ) printf("\n");
     sqlite3VdbePrintOp(0, i, &p->aOp[i]);
     test_addop_breakpoint();
   }
@@ -1646,9 +1638,6 @@ static void initMemArray(Mem *p, int N, sqlite3 *db, u16 flags){
     p->szMalloc = 0;
 #ifdef SQLITE_DEBUG
     p->pScopyFrom = 0;
-#endif
-#ifdef SQLITE_DEBUG_COLUMNCACHE
-    p->iTabColHash = 0;
 #endif
     p++;
   }

src/vdbemem.c

@@ -934,9 +934,6 @@ void sqlite3VdbeMemAboutToChange(Vdbe *pVdbe, Mem *pMem){
     }
   }
   pMem->pScopyFrom = 0;
-#ifdef SQLITE_DEBUG_COLUMN_CACHE
-  pMem->iTabColHash = 0;
-#endif
 }
 #endif /* SQLITE_DEBUG */
 
@@ -957,9 +954,6 @@ void sqlite3VdbeMemShallowCopy(Mem *pTo, const Mem *pFrom, int srcType){
   assert( pTo->db==pFrom->db );
   if( VdbeMemDynamic(pTo) ){ vdbeClrCopy(pTo,pFrom,srcType); return; }
   memcpy(pTo, pFrom, MEMCELLSIZE);
-#ifdef SQLITE_DEBUG_COLUMNCACHE
-  pTo->iTabColHash = pFrom->iTabColHash;
-#endif
   if( (pFrom->flags&MEM_Static)==0 ){
     pTo->flags &= ~(MEM_Dyn|MEM_Static|MEM_Ephem);
     assert( srcType==MEM_Ephem || srcType==MEM_Static );
@@ -977,9 +971,6 @@ int sqlite3VdbeMemCopy(Mem *pTo, const Mem *pFrom){
   assert( (pFrom->flags & MEM_RowSet)==0 );
   if( VdbeMemDynamic(pTo) ) vdbeMemClearExternAndSetNull(pTo);
   memcpy(pTo, pFrom, MEMCELLSIZE);
-#ifdef SQLITE_DEBUG_COLUMNCACHE
-  pTo->iTabColHash = pFrom->iTabColHash;
-#endif
   pTo->flags &= ~MEM_Dyn;
   if( pTo->flags&(MEM_Str|MEM_Blob) ){
     if( 0==(pFrom->flags&MEM_Static) ){

src/where.c

@@ -802,7 +802,6 @@ static void constructAutomaticIndex(
   VdbeComment((v, "for %s", pTable->zName));
 
   /* Fill the automatic index with content */
-  sqlite3ExprCachePush(pParse);
   pTabItem = &pWC->pWInfo->pTabList->a[pLevel->iFrom];
   if( pTabItem->fg.viaCoroutine ){
     int regYield = pTabItem->regReturn;
@@ -839,7 +838,6 @@ static void constructAutomaticIndex(
   sqlite3VdbeChangeP5(v, SQLITE_STMTSTATUS_AUTOINDEX);
   sqlite3VdbeJumpHere(v, addrTop);
   sqlite3ReleaseTempReg(pParse, regRecord);
-  sqlite3ExprCachePop(pParse);
   
   /* Jump here when skipping the initialization */
   sqlite3VdbeJumpHere(v, addrInit);
@@ -5077,7 +5075,6 @@ void sqlite3WhereEnd(WhereInfo *pWInfo){
   /* Generate loop termination code.
   */
   VdbeModuleComment((v, "End WHERE-core"));
-  sqlite3ExprCacheClear(pParse);
   for(i=pWInfo->nLevel-1; i>=0; i--){
     int addr;
     pLevel = &pWInfo->a[i];

src/wherecode.c

@@ -347,7 +347,6 @@ static void codeApplyAffinity(Parse *pParse, int base, int n, char *zAff){
   /* Code the OP_Affinity opcode if there is anything left to do. */
   if( n>0 ){
     sqlite3VdbeAddOp4(v, OP_Affinity, base, n, 0, zAff, n);
-    sqlite3ExprCacheAffinityChange(pParse, base, n);
   }
 }
 
@@ -1256,7 +1255,6 @@ Bitmask sqlite3WhereCodeOneLoopStart(
     int nConstraint = pLoop->nLTerm;
     int iIn;    /* Counter for IN constraints */
 
-    sqlite3ExprCachePush(pParse);
     iReg = sqlite3GetTempRange(pParse, nConstraint+2);
     addrNotFound = pLevel->addrBrk;
     for(j=0; j<nConstraint; j++){
@@ -1329,7 +1327,6 @@ Bitmask sqlite3WhereCodeOneLoopStart(
     **
     **    sqlite3ReleaseTempRange(pParse, iReg, nConstraint+2);
     */
-    sqlite3ExprCachePop(pParse);
   }else
 #endif /* SQLITE_OMIT_VIRTUALTABLE */
 
@@ -1422,7 +1419,6 @@ Bitmask sqlite3WhereCodeOneLoopStart(
       VdbeCoverageIf(v, pX->op==TK_LE);
       VdbeCoverageIf(v, pX->op==TK_LT);
       VdbeCoverageIf(v, pX->op==TK_GE);
-      sqlite3ExprCacheAffinityChange(pParse, r1, 1);
       sqlite3ReleaseTempReg(pParse, rTemp);
     }else{
       sqlite3VdbeAddOp2(v, bRev ? OP_Last : OP_Rewind, iCur, addrHalt);
@@ -1457,7 +1453,6 @@ Bitmask sqlite3WhereCodeOneLoopStart(
     if( testOp!=OP_Noop ){
       iRowidReg = ++pParse->nMem;
       sqlite3VdbeAddOp2(v, OP_Rowid, iCur, iRowidReg);
-      sqlite3ExprCacheStore(pParse, iCur, -1, iRowidReg);
       sqlite3VdbeAddOp3(v, testOp, memEndValue, addrBrk, iRowidReg);
       VdbeCoverageIf(v, testOp==OP_Le);
       VdbeCoverageIf(v, testOp==OP_Lt);
@@ -1683,7 +1678,6 @@ Bitmask sqlite3WhereCodeOneLoopStart(
     nConstraint = nEq;
     if( pRangeEnd ){
       Expr *pRight = pRangeEnd->pExpr->pRight;
-      sqlite3ExprCacheRemove(pParse, regBase+nEq, 1);
       codeExprOrVector(pParse, pRight, regBase+nEq, nTop);
       whereLikeOptimizationStringFixup(v, pLevel, pRangeEnd);
       if( (pRangeEnd->wtFlags & TERM_VNULL)==0
@@ -1708,7 +1702,6 @@ Bitmask sqlite3WhereCodeOneLoopStart(
       }
     }else if( bStopAtNull ){
       sqlite3VdbeAddOp2(v, OP_Null, 0, regBase+nEq);
-      sqlite3ExprCacheRemove(pParse, regBase+nEq, 1);
       endEq = 0;
       nConstraint++;
     }
@@ -1742,7 +1735,6 @@ Bitmask sqlite3WhereCodeOneLoopStart(
       )){
         iRowidReg = ++pParse->nMem;
         sqlite3VdbeAddOp2(v, OP_IdxRowid, iIdxCur, iRowidReg);
-        sqlite3ExprCacheStore(pParse, iCur, -1, iRowidReg);
         sqlite3VdbeAddOp3(v, OP_NotExists, iCur, 0, iRowidReg);
         VdbeCoverage(v);
       }else{
@@ -1977,23 +1969,23 @@ Bitmask sqlite3WhereCodeOneLoopStart(
           ** row will be skipped in subsequent sub-WHERE clauses.
           */
           if( (pWInfo->wctrlFlags & WHERE_DUPLICATES_OK)==0 ){
-            int r;
             int iSet = ((ii==pOrWc->nTerm-1)?-1:ii);
             if( HasRowid(pTab) ){
-              r = sqlite3ExprCodeGetColumn(pParse, pTab, -1, iCur, regRowid, 0);
+              sqlite3ExprCodeGetColumnOfTable(v, pTab, iCur, -1, regRowid);
               jmp1 = sqlite3VdbeAddOp4Int(v, OP_RowSetTest, regRowset, 0,
-                                           r,iSet);
+                                          regRowid, iSet);
               VdbeCoverage(v);
             }else{
               Index *pPk = sqlite3PrimaryKeyIndex(pTab);
               int nPk = pPk->nKeyCol;
               int iPk;
+              int r;
 
               /* Read the PK into an array of temp registers. */
               r = sqlite3GetTempRange(pParse, nPk);
               for(iPk=0; iPk<nPk; iPk++){
                 int iCol = pPk->aiColumn[iPk];
-                sqlite3ExprCodeGetColumnToReg(pParse, pTab, iCol, iCur, r+iPk);
+                sqlite3ExprCodeGetColumnOfTable(v, pTab, iCur, iCol, r+iPk);
               }
 
               /* Check if the temp table already contains this key. If so,
@@ -2226,7 +2218,6 @@ Bitmask sqlite3WhereCodeOneLoopStart(
     pLevel->addrFirst = sqlite3VdbeCurrentAddr(v);
     sqlite3VdbeAddOp2(v, OP_Integer, 1, pLevel->iLeftJoin);
     VdbeComment((v, "record LEFT JOIN hit"));
-    sqlite3ExprCacheClear(pParse);
     for(pTerm=pWC->a, j=0; j<pWC->nTerm; j++, pTerm++){
       testcase( pTerm->wtFlags & TERM_VIRTUAL );
       testcase( pTerm->wtFlags & TERM_CODED );

test/btree02.test

@@ -33,6 +33,8 @@ do_test btree02-110 {
   db eval BEGIN
   set i 0
   db eval {SELECT a, ax, b, cnt FROM t1 CROSS JOIN t3 WHERE b IS NOT NULL} {
+    if {$a==""} {set a 0}
+    if {$b==""} {set b 0}    
     db eval {INSERT INTO t2(x,y) VALUES($b,$cnt)}
     # puts "a,b,cnt = ($a,$b,$cnt)"
     incr i
@@ -47,6 +49,6 @@ do_test btree02-110 {
     db eval {COMMIT; BEGIN}
   }  
   db one {COMMIT; SELECT count(*) FROM t1;}
-} {20}
+} {27}
 
 finish_test