From 3b908d41a0d3800a6ebe5dff42f4117fc342105c Mon Sep 17 00:00:00 2001
From: dan <dan@noemail.net>
Date: Tue, 8 Nov 2016 19:22:32 +0000
Subject: [PATCH] Avoid superfluous cursor seeks in "INSERT OR REPLACE"
 statements.

FossilOrigin-Name: bec5b6d4d083556d111a89186b4f7b35b5e7cebf
---
 manifest      | 16 ++++++++--------
 manifest.uuid |  2 +-
 src/insert.c  | 16 +++++++++++++++-
 src/vdbe.c    |  2 ++
 4 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/manifest b/manifest
index 27b1efadaa..9c94df9efd 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Avoid\sgenerating\sOP_TableLock\sunnecessary\sinstructions\son\sbtrees\sthat\s\nare\snot\ssharable.
-D 2016-11-08T17:19:22.006
+C Avoid\ssuperfluous\scursor\sseeks\sin\s"INSERT\sOR\sREPLACE"\sstatements.
+D 2016-11-08T19:22:32.125
 F Makefile.in 6fd48ffcf7c2deea7499062d1f3747f986c19678
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc e0217f2d35a0448abbe4b066132ae20136e8b408
@@ -349,7 +349,7 @@ 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 2d5e197f2f60351937b201196965fd14cd88489c
+F src/insert.c 8c1346304a9a386b036652475296103bae27e0a1
 F src/legacy.c 75d3023be8f0d2b99d60f905090341a03358c58e
 F src/loadext.c 5d6642d141c07d366e43d359e94ec9de47add41d
 F src/main.c 694ac90557abdaa62151a6090670e107b0f2c2ab
@@ -454,7 +454,7 @@ F src/update.c 8179e699dbd45b92934fd02d3d8e3732e8da8802
 F src/utf.c 699001c79f28e48e9bcdf8a463da029ea660540c
 F src/util.c 3e2da6101888d073e79ecc6af5e0a2f70fa1e498
 F src/vacuum.c 33c174b28886b2faf26e503b5a49a1c01a9b1c16
-F src/vdbe.c 2edc4fa8a825c79a929766f50bc800ea158646d2
+F src/vdbe.c 20307c93ad55af6ab8f50b17147a4704d4f17dab
 F src/vdbe.h c044be7050ac6bf596eecc6ab159f5dbc020a3b7
 F src/vdbeInt.h d8a56a491b752dbb5f671963b8c861ec72ea875e
 F src/vdbeapi.c 97129bec6b1553da50d8e73f523c278bda66d9f6
@@ -1530,7 +1530,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P c2f84f637f994c3b4522b48161185a4a2c5bca23
-R 10ce1648dec21a665da138671841929b
-U drh
-Z 8856bb137559d0d48b8e63db91d4ed8e
+P 8cb8516d2009d52d35a22263e4c892f162b34b81
+R 36e33fba7941647bfb228c5ae67f2b63
+U dan
+Z a11930824d648f16d0f222498c7f4b67
diff --git a/manifest.uuid b/manifest.uuid
index dcfe87a3ac..0835b36ebc 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-8cb8516d2009d52d35a22263e4c892f162b34b81
\ No newline at end of file
+bec5b6d4d083556d111a89186b4f7b35b5e7cebf
\ No newline at end of file
diff --git a/src/insert.c b/src/insert.c
index 8167ff78c5..6ea3810a2a 100644
--- a/src/insert.c
+++ b/src/insert.c
@@ -995,12 +995,26 @@ void sqlite3Insert(
 #endif
     {
       int isReplace;    /* Set to true if constraints may cause a replace */
+      int bUseSeek;     /* True to use OPFLAG_SEEKRESULT */
       sqlite3GenerateConstraintChecks(pParse, pTab, aRegIdx, iDataCur, iIdxCur,
           regIns, 0, ipkColumn>=0, onError, endOfLoop, &isReplace, 0
       );
       sqlite3FkCheck(pParse, pTab, 0, regIns, 0, 0);
+
+      /* Set the OPFLAG_USESEEKRESULT flag if either (a) there are no REPLACE
+      ** constraints or (b) there are no triggers and this table is not a
+      ** parent table in a foreign key constraint. It is safe to set the
+      ** flag in the second case as if any REPLACE constraint is hit, an
+      ** OP_Delete or OP_IdxDelete instruction will be executed on each 
+      ** cursor that is disturbed. And these instructions both clear the
+      ** VdbeCursor.seekResult variable, disabling the OPFLAG_USESEEKRESULT
+      ** functionality.  */
+      bUseSeek = (isReplace==0 || (pTrigger==0 &&
+          ((db->flags & SQLITE_ForeignKeys)==0 || sqlite3FkReferences(pTab)==0)
+      ));
       sqlite3CompleteInsertion(pParse, pTab, iDataCur, iIdxCur,
-                               regIns, aRegIdx, 0, appendFlag, isReplace==0);
+          regIns, aRegIdx, 0, appendFlag, bUseSeek
+      );
     }
   }
 
diff --git a/src/vdbe.c b/src/vdbe.c
index 8b47a37833..c2abeced04 100644
--- a/src/vdbe.c
+++ b/src/vdbe.c
@@ -4554,6 +4554,7 @@ case OP_Delete: {
 
   rc = sqlite3BtreeDelete(pC->uc.pCursor, pOp->p5);
   pC->cacheStatus = CACHE_STALE;
+  pC->seekResult = 0;
   if( rc ) goto abort_due_to_error;
 
   /* Invoke the update-hook if required. */
@@ -5109,6 +5110,7 @@ case OP_IdxDelete: {
   }
   assert( pC->deferredMoveto==0 );
   pC->cacheStatus = CACHE_STALE;
+  pC->seekResult = 0;
   break;
 }