Improvements to the iIdxNoSeek optimization of sqlite3GenerateRowDelete()

so that it is automatically disabled for BEFORE triggers but works in all
other cases.

FossilOrigin-Name: 3178ec4c27efc4ff84bcd17ddb17ec50a6ac96b3

manifest

@@ -1,5 +1,5 @@
-C Critical\sfix\sto\sthe\sprevious\scheck-in\sso\sthat\sit\sworks\swhen\sthere\sare\nBEFORE\striggers\sthat\smove\sthe\scursor\sbefore\sthe\sOP_Delete\shas\sa\schance\sto\nbe\sapplied.
-D 2017-01-07T14:26:28.809
+C Improvements\sto\sthe\siIdxNoSeek\soptimization\sof\ssqlite3GenerateRowDelete()\nso\sthat\sit\sis\sautomatically\sdisabled\sfor\sBEFORE\striggers\sbut\sworks\sin\sall\nother\scases.
+D 2017-01-07T14:47:03.531
 F Makefile.in 41bd4cad981487345c4a84081074bcdb876e4b2e
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc b8ca53350ae545e3562403d5da2a69cec79308da
@@ -340,7 +340,7 @@ F src/complete.c a3634ab1e687055cd002e11b8f43eb75c17da23e
 F src/ctime.c 9f2296a4e5d26ebf0e0d95a0af4628f1ea694e7a
 F src/date.c dc3f1391d9297f8c748132813aaffcb117090d6e
 F src/dbstat.c 19ee7a4e89979d4df8e44cfac7a8f905ec89b77d
-F src/delete.c 4220f4feee7fddefc1e73e5ade1ed82ffe8dc92a
+F src/delete.c a84f6229ccb9448460c287248024ceb70e10baab
 F src/expr.c f06f41e5e5daca10fb090e70a2502dcc0dbc992b
 F src/fault.c 460f3e55994363812d9d60844b2a6de88826e007
 F src/fkey.c 2e9aabe1aee76273aff8a84ee92c464e095400ae
@@ -350,7 +350,7 @@ F src/hash.c 63d0ee752a3b92d4695b2b1f5259c4621b2cfebd
 F src/hash.h ab34c5c54a9e9de2e790b24349ba5aab3dbb4fd4
 F src/hwtime.h 747c1bbe9df21a92e9c50f3bbec1de841dc5e5da
 F src/in-operator.md 10cd8f4bcd225a32518407c2fb2484089112fd71
-F src/insert.c 3b7fbb149ef249269bfbedabbe8fd706ef9a2317
+F src/insert.c ad2a0b2757a23b6f9297ee414eeab22b52fbde75
 F src/legacy.c 75d3023be8f0d2b99d60f905090341a03358c58e
 F src/loadext.c 5d6642d141c07d366e43d359e94ec9de47add41d
 F src/main.c e207b81542d13b9f13d61e78ca441f9781f055b0
@@ -1543,7 +1543,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P f0495c5133d0dc04d63521136d6b9ca440792cdf
-R 21f1a5c5760681e8d66bbbeed4342953
+P db2c0960ffb3b396b20e0441d3edb812254c82bc
+R 7bbc97d23d01181c7fdd8aa9c81894e1
 U drh
-Z 06625003bcd408124313c9f36986c7f6
+Z 5c5df114c2b0c58ce035451bb180f71f

manifest.uuid

@@ -1 +1 @@
-db2c0960ffb3b396b20e0441d3edb812254c82bc
+3178ec4c27efc4ff84bcd17ddb17ec50a6ac96b3

src/delete.c

@@ -519,9 +519,8 @@ void sqlite3DeleteFrom(
 #endif
     {
       int count = (pParse->nested==0);    /* True to count changes */
-      int iIdxNoSeek = bComplex ? -1 : aiCurOnePass[1];
       sqlite3GenerateRowDelete(pParse, pTab, pTrigger, iDataCur, iIdxCur,
-          iKey, nKey, count, OE_Default, eOnePass, iIdxNoSeek);
+          iKey, nKey, count, OE_Default, eOnePass, aiCurOnePass[1]);
     }
   
     /* End of the loop over all rowids/primary-keys. */
@@ -610,6 +609,8 @@ delete_from_cleanup:
 **   If iIdxNoSeek is a valid cursor number (>=0) not equal to iDataCur,
 **   then it identifies an index cursor (from within array of cursors
 **   starting at iIdxCur) that already points to the index entry to be deleted.
+**   Except, this optimization is disabled if there are BEFORE triggers since
+**   the trigger body might have moved the cursor.
 */
 void sqlite3GenerateRowDelete(
   Parse *pParse,     /* Parsing context */
@@ -682,11 +683,16 @@ void sqlite3GenerateRowDelete(
     ** row to be deleted again. It may be that the BEFORE triggers moved
     ** the cursor or already deleted the row that the cursor was
     ** pointing to.
+    **
+    ** Also disable the iIdxNoSeek optimization since the BEFORE trigger
+    ** may have moved that cursor.
     */
     if( addrStart<sqlite3VdbeCurrentAddr(v) ){
       sqlite3VdbeAddOp4Int(v, opSeek, iDataCur, iLabel, iPk, nPk);
       VdbeCoverageIf(v, opSeek==OP_NotExists);
       VdbeCoverageIf(v, opSeek==OP_NotFound);
+      testcase( iIdxNoSeek>=0 );
+      iIdxNoSeek = -1;
     }
 
     /* Do FK processing. This call checks that any FK constraints that

src/insert.c

@@ -1651,8 +1651,7 @@ void sqlite3GenerateConstraintChecks(
         }
         sqlite3GenerateRowDelete(pParse, pTab, pTrigger, iDataCur, iIdxCur,
             regR, nPkField, 0, OE_Replace,
-            (pIdx==pPk ? ONEPASS_SINGLE : ONEPASS_OFF),
-            (pTrigger ? -1 : iThisCur));
+            (pIdx==pPk ? ONEPASS_SINGLE : ONEPASS_OFF), iThisCur);
         seenReplace = 1;
         break;
       }