From: drh <drh@noemail.net>
Date: Tue, 5 Jun 2018 20:45:20 +0000 (+0000)
Subject: Add the OP_IfNoHope and OP_SeekHit opcodes used to reduce the number of
X-Git-Tag: version-3.25.0~207^2~6
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=8c2b6d784b44c601ea600e8cfca9a222ce66b54b;p=thirdparty%2Fsqlite.git

Add the OP_IfNoHope and OP_SeekHit opcodes used to reduce the number of
unnecessary sqlite3BtreeMovetoUnpacked() calls when checking for an early
exit on IN-operator loops.  Futher optimizations are likely possible here.

FossilOrigin-Name: 6bf251af4347165a470d39457d61ab6d2a06c206db8f30bd8be5dbb388ae8a5b
---

diff --git a/manifest b/manifest
index ef0a40552a..f16c3e72be 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Use\san\sOP_NotFound\sopcode\sto\scancel\sfutile\sIN\soperators\searly.\s\sThe\scurrent\nimplementation\sis\ssuboptimal\sbecause\sit\salways\sruns\steh\sOP_NotFound.\s\sThis\nstill\sneeds\sto\sbe\senhanced\sto\sonly\sdo\sthe\sOP_NotFound\sif\sno\sresults\shave\sbeen\nseen\son\sthe\scurrent\sloop.
-D 2018-06-05T15:16:25.289
+C Add\sthe\sOP_IfNoHope\sand\sOP_SeekHit\sopcodes\sused\sto\sreduce\sthe\snumber\sof\nunnecessary\ssqlite3BtreeMovetoUnpacked()\scalls\swhen\schecking\sfor\san\searly\nexit\son\sIN-operator\sloops.\s\sFuther\soptimizations\sare\slikely\spossible\shere.
+D 2018-06-05T20:45:20.959
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F Makefile.in bfc40f350586923e0419d2ea4b559c37ec10ee4b6e210e08c14401f8e340f0da
@@ -565,9 +565,9 @@ F src/upsert.c 47edd408cc73f8d3c00a140550d1ad180b407c146285947969dd09874802bf88
 F src/utf.c 810fbfebe12359f10bc2a011520a6e10879ab2a163bcb26c74768eab82ea62a5
 F src/util.c d9eb0a6c4aae1b00a7369eadd7ca0bbe946cb4c953b6751aa20d357c2f482157
 F src/vacuum.c 37730af7540033135909ecaee3667dddec043293428d8718546d0d64ba4a5025
-F src/vdbe.c fcec6e9ad743f92f0a557f0b61728d001581ee96e18c3e5c7d09702afde79b38
+F src/vdbe.c 1c429876d32a96fdebd8f8b31f735c6236a8fb04395e8f731784767b909d2504
 F src/vdbe.h e3f43bcc27ff30b0f25a6104d0cb5657e1c4b5e1b5cd2dd2216d5bcc2156a746
-F src/vdbeInt.h 42d3e65ea0c664f6d9bc9a53de645c0baf8566ff0188409ff3b8d2abc327bc17
+F src/vdbeInt.h d299d7a19853463dac418de0d97f2dd9cb4ddb495a45c93364e2daee109ba0ef
 F src/vdbeapi.c 765a0bbe01311626417de6cb743f7f25f9f98435c98a9df4bb0714d11014633d
 F src/vdbeaux.c b00d35805a2b326d1371ab7ce8f3a95c8af35b1431367ffe482fc2c735d69fb1
 F src/vdbeblob.c f5c70f973ea3a9e915d1693278a5f890dc78594300cf4d54e64f2b0917c94191
@@ -579,9 +579,9 @@ F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
 F src/wal.c aa9cffc7a2bad6b826a86c8562dd4978398720ed41cb8ee7aa9d054eb8b456a0
 F src/wal.h 8de5d2d3de0956d6f6cb48c83a4012d5f227b8fe940f3a349a4b7e85ebcb492a
 F src/walker.c da987a20d40145c0a03c07d8fefcb2ed363becc7680d0500d9c79915591f5b1f
-F src/where.c a16f982d998e87067ea64d30602e008a24f767e6e502d7cdcddf0c858cdd9392
+F src/where.c 83b6cf94d98ff9a2185071aeed664a57922999a6dd58a03dbb379d472314e4b2
 F src/whereInt.h b6ab96d9c1e48d029eaaee8f9b6d05e6a2405af0ad68f684e75f21c46837ae11
-F src/wherecode.c f941a484fd9f7a197099efe384be7a64c5588f27bbf92151705dae92eea7dbfc
+F src/wherecode.c 12d88d0195a50b456c5dbeb3c44cb7d7087f591526968e8bde7a38b5534cd0ee
 F src/whereexpr.c e90b2e76dcabc81edff56633bf281bc01d93b71e0c81482dc06925ce39f5844a
 F test/8_3_names.test ebbb5cd36741350040fd28b432ceadf495be25b2
 F test/affinity2.test a6d901b436328bd67a79b41bb0ac2663918fe3bd
@@ -1730,7 +1730,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 047295c588e9fdf2ffa4e69e166f177fd193309531dc6a9ac755fb7a763adb72
-R 5115dc97bd8a224dc2a595e1eda36012
+P 87a9fc504f9a78caf7a7949cc7ada0a19d61bfab51bb49a00a1607194c116212
+R 06e6068952816b400d67d388d7704be4
 U drh
-Z 3e5cea1662f3befc7bce81830cbd86be
+Z 5b6bba2950cd0e23a4c3733c8955eb63
diff --git a/manifest.uuid b/manifest.uuid
index 20f95cb085..9568d071fe 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-87a9fc504f9a78caf7a7949cc7ada0a19d61bfab51bb49a00a1607194c116212
\ No newline at end of file
+6bf251af4347165a470d39457d61ab6d2a06c206db8f30bd8be5dbb388ae8a5b
\ No newline at end of file
diff --git a/src/vdbe.c b/src/vdbe.c
index 27bf56eb46..4a325b207b 100644
--- a/src/vdbe.c
+++ b/src/vdbe.c
@@ -4034,6 +4034,25 @@ seek_not_found:
   break;
 }
 
+/* Opcode: SeekHit P1 P2 * * *
+** Synopsis: seekHit=P2
+**
+** Set the seekHit flag on cursor P1 to the value in P2.
+** The seekHit flag is used by the IfNoHope opcode.
+**
+** P1 must be a valid b-tree cursor.  P2 must be a boolean value,
+** either 0 or 1.
+*/
+case OP_SeekHit: {
+  VdbeCursor *pC;
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  assert( pOp->p2==0 || pOp->p2==1 );
+  pC->seekHit = pOp->p2 & 1;
+  break;
+}
+
 /* Opcode: Found P1 P2 P3 P4 *
 ** Synopsis: key=r[P3@P4]
 **
@@ -4068,7 +4087,34 @@ seek_not_found:
 ** advanced in either direction.  In other words, the Next and Prev
 ** opcodes do not work after this operation.
 **
-** See also: Found, NotExists, NoConflict
+** See also: Found, NotExists, NoConflict, IfNoHope
+*/
+/* Opcode: IfNoHope P1 P2 P3 P4 *
+** Synopsis: key=r[P3@P4]
+**
+** Register P3 is the first of P4 registers that form an unpacked
+** record.
+**
+** Cursor P1 is on an index btree.  If the seekHit flag is set on P1, then
+** this opcode is a no-op.  But if the seekHit flag of P1 is clear, then
+** check to see if there is any entry in P1 that matches the
+** prefix identified by P3 and P4.  If no entry matches the prefix,
+** jump to P2.  Otherwise fall through.
+**
+** This opcode behaves like OP_NotFound if the seekHit
+** flag is clear and it behaves like OP_Noop if the seekHit flag is set.
+**
+** This opcode is used in IN clause processing for a multi-column key.
+** If an IN clause is attached to an element of the key other than the
+** left-most element, and if there are no matches on the most recent
+** seek over the whole key, then it might be that one of the key element
+** to the left is prohibiting a match, and hence there is "no hope" of
+** any match regardless of how many IN clause elements are checked.
+** In such a case, we abandon the IN clause search early, using this
+** opcode.  The opcode name comes from the fact that the
+** jump is taken if there is "no hope" of achieving a match.
+**
+** See also: NotFound, SeekHit
 */
 /* Opcode: NoConflict P1 P2 P3 P4 *
 ** Synopsis: key=r[P3@P4]
@@ -4093,6 +4139,14 @@ seek_not_found:
 **
 ** See also: NotFound, Found, NotExists
 */
+case OP_IfNoHope: {     /* jump, in3 */
+  VdbeCursor *pC;
+  assert( pOp->p1>=0 && pOp->p1<p->nCursor );
+  pC = p->apCsr[pOp->p1];
+  assert( pC!=0 );
+  if( pC->seekHit ) break;
+  /* Fall through into OP_NotFound */
+}
 case OP_NoConflict:     /* jump, in3 */
 case OP_NotFound:       /* jump, in3 */
 case OP_Found: {        /* jump, in3 */
diff --git a/src/vdbeInt.h b/src/vdbeInt.h
index 0f10e3759d..dd8e29108a 100644
--- a/src/vdbeInt.h
+++ b/src/vdbeInt.h
@@ -85,6 +85,7 @@ struct VdbeCursor {
   Bool isEphemeral:1;     /* True for an ephemeral table */
   Bool useRandomRowid:1;  /* Generate new record numbers semi-randomly */
   Bool isOrdered:1;       /* True if the table is not BTREE_UNORDERED */
+  Bool seekHit:1;         /* See the OP_SeekHit and OP_IfNoHope opcodes */
   Btree *pBtx;            /* Separate file holding temporary table */
   i64 seqCount;           /* Sequence counter */
   int *aAltMap;           /* Mapping from table to index column numbers */
diff --git a/src/where.c b/src/where.c
index d31e0bb09d..bfb848f426 100644
--- a/src/where.c
+++ b/src/where.c
@@ -5084,7 +5084,7 @@ void sqlite3WhereEnd(WhereInfo *pWInfo){
         sqlite3VdbeJumpHere(v, pIn->addrInTop+1);
         if( pIn->eEndLoopOp!=OP_Noop ){
           if( pIn->nPrefix ){
-            sqlite3VdbeAddOp4Int(v, OP_NotFound, pLevel->iIdxCur,
+            sqlite3VdbeAddOp4Int(v, OP_IfNoHope, pLevel->iIdxCur,
                               sqlite3VdbeCurrentAddr(v)+2,
                               pIn->iBase, pIn->nPrefix);
             VdbeCoverage(v);
diff --git a/src/wherecode.c b/src/wherecode.c
index 1c653c9f59..a20a9808e1 100644
--- a/src/wherecode.c
+++ b/src/wherecode.c
@@ -1664,6 +1664,9 @@ Bitmask sqlite3WhereCodeOneLoopStart(
       ** above has already left the cursor sitting on the correct row,
       ** so no further seeking is needed */
     }else{
+      if( pLoop->wsFlags & WHERE_IN_ABLE ){
+        sqlite3VdbeAddOp1(v, OP_SeekHit, iIdxCur);
+      }
       op = aStartOp[(start_constraints<<2) + (startEq<<1) + bRev];
       assert( op!=0 );
       sqlite3VdbeAddOp4Int(v, op, iIdxCur, addrNxt, regBase, nConstraint);
@@ -1727,6 +1730,10 @@ Bitmask sqlite3WhereCodeOneLoopStart(
       testcase( op==OP_IdxLE );  VdbeCoverageIf(v, op==OP_IdxLE );
     }
 
+    if( pLoop->wsFlags & WHERE_IN_ABLE ){
+      sqlite3VdbeAddOp2(v, OP_SeekHit, iIdxCur, 1);
+    }
+
     /* Seek the table cursor, if required */
     if( omitTable ){
       /* pIdx is a covering index.  No need to access the main table. */