From: drh <drh@noemail.net>
Date: Fri, 19 Sep 2014 15:28:33 +0000 (+0000)
Subject: The OP_Column opcode runs faster and is smaller by manually in-lining the
X-Git-Tag: version-3.8.7~97
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=7b5ebcaf26d6640f5b4997732c8c5161feda4c9e;p=thirdparty%2Fsqlite.git

The OP_Column opcode runs faster and is smaller by manually in-lining the
code that persists string values in the output register.

FossilOrigin-Name: 36b613ccf0ddb764af90841994da91b7fcaa8f00
---

diff --git a/manifest b/manifest
index 013d54f55b..611616d0c2 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Add\sthe\ssqlite3VdbeMemClearAndResize()\sfunction.\s\sFix\sa\ssorting-index\nprefilter\sproblem.
-D 2014-09-19T04:42:38.074
+C The\sOP_Column\sopcode\sruns\sfaster\sand\sis\ssmaller\sby\smanually\sin-lining\sthe\ncode\sthat\spersists\sstring\svalues\sin\sthe\soutput\sregister.
+D 2014-09-19T15:28:33.728
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in cf57f673d77606ab0f2d9627ca52a9ba1464146a
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -288,7 +288,7 @@ F src/update.c 729f6f18fc27740591d085e1172cebe311144bf0
 F src/utf.c fc6b889ba0779b7722634cdeaa25f1930d93820c
 F src/util.c 4006c01772bd8d8ac4306d523bbcee41d3e392d8
 F src/vacuum.c 59f03f92bcff57faa6a8ca256eb29ccddfb0614a
-F src/vdbe.c 7bc115e540282b1bfff9b43205cbf6528e6398a6
+F src/vdbe.c 9f2a0a2dfa06e99feabd754e9be3a436ac3cf97d
 F src/vdbe.h 09f5b4e3719fa454f252322b1cdab5cf1f361327
 F src/vdbeInt.h f177bed1ec8d4eb5c7089f012aeb95f374745735
 F src/vdbeapi.c e9e33b59834e3edc8790209765e069874c269d9d
@@ -1198,8 +1198,7 @@ F tool/vdbe_profile.tcl 67746953071a9f8f2f668b73fe899074e2c6d8c1
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh 0abfd78ceb09b7f7c27c688c8e3fe93268a13b32
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P 9c09ac353df6041808cace41880f4729ee73f5e1 72727b68cd07969165f1f0943cc7e1a265436653
-R a5960c77be61d5e92e67de5776336365
-T +closed 72727b68cd07969165f1f0943cc7e1a265436653
+P 987a7a211913b3949da20e43423af376f72a28ba
+R 03eb020eed7bf3a8527e5a4e8f2d486b
 U drh
-Z 88c7b85ca090541e4ecff878bb673522
+Z 0d995c472ae8295ead3b2ebd0d73fc53
diff --git a/manifest.uuid b/manifest.uuid
index 6dc6c4d043..f8720261f1 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-987a7a211913b3949da20e43423af376f72a28ba
\ No newline at end of file
+36b613ccf0ddb764af90841994da91b7fcaa8f00
\ No newline at end of file
diff --git a/src/vdbe.c b/src/vdbe.c
index 25a33a63f7..0baacef4c0 100644
--- a/src/vdbe.c
+++ b/src/vdbe.c
@@ -2482,7 +2482,21 @@ case OP_Column: {
   pDest->enc = encoding;
 
 op_column_out:
-  Deephemeralize(pDest);
+  /* If the column value is an ephemeral string, go ahead and persist
+  ** that string in case the cursor moves before the column value is
+  ** used.  The following code does the equivalent of Deephemeralize()
+  ** but does it faster. */
+  if( (pDest->flags & MEM_Ephem)!=0 && pDest->z ){
+    u16 f = pDest->flags & (MEM_Str|MEM_Blob);
+    assert( f!=0 );
+    zData = (const u8*)pDest->z;
+    len = pDest->n;
+    if( sqlite3VdbeMemClearAndResize(pDest, len+2) ) goto no_mem;
+    memcpy(pDest->z, zData, len);
+    pDest->z[len] = 0;
+    pDest->z[len+1] = 0;
+    pDest->flags = f|MEM_Term;
+  }
 op_column_error:
   UPDATE_MAX_BLOBSIZE(pDest);
   REGISTER_TRACE(pOp->p3, pDest);