From: drh <drh@noemail.net>
Date: Fri, 21 Sep 2018 13:07:14 +0000 (+0000)
Subject: Optimization to the OP_MakeRecord opcode makes speed-check.sh run about
X-Git-Tag: version-3.26.0~139
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=0d7f0ccd966442b4d887b40e84e6b005a38e9803;p=thirdparty%2Fsqlite.git

Optimization to the OP_MakeRecord opcode makes speed-check.sh run about
1.1 million cycles faster, and results in a slightly smaller library.

FossilOrigin-Name: d10e63629183f6daf0c263cd4dae052a3786c8c1480b3b6a73124b3315e41951
---

diff --git a/manifest b/manifest
index c7f29e6415..20bfd8e4f6 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Minor\scode\ssimplification.
-D 2018-09-20T20:43:28.118
+C Optimization\sto\sthe\sOP_MakeRecord\sopcode\smakes\sspeed-check.sh\srun\sabout\n1.1\smillion\scycles\sfaster,\sand\sresults\sin\sa\sslightly\ssmaller\slibrary.
+D 2018-09-21T13:07:14.225
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F Makefile.in 01e95208a78b57d056131382c493c963518f36da4c42b12a97eb324401b3a334
@@ -573,7 +573,7 @@ F src/upsert.c 0dd81b40206841814d46942a7337786932475f085716042d0cb2fc7791bf8ca4
 F src/utf.c 810fbfebe12359f10bc2a011520a6e10879ab2a163bcb26c74768eab82ea62a5
 F src/util.c d9eb0a6c4aae1b00a7369eadd7ca0bbe946cb4c953b6751aa20d357c2f482157
 F src/vacuum.c 36e7d21a20c0bf6ef4ef7c399d192b5239410b7c4d3c1070fba4e30810d0b855
-F src/vdbe.c 7433ac76608b80b745f57b8544416dc0178db52ce2cc806a10353309e5f781fb
+F src/vdbe.c c7416f6b5e47efbdf09c73a3984ecc68666151ae894c27fb1e51d51bbba62082
 F src/vdbe.h 5081dcc497777efe5e9ebe7330d283a044a005e4bdda2e2e984f03bf89a0d907
 F src/vdbeInt.h f1f35f70460698d8f5a2bdef1001114babf318e2983a067804e2ae077d8e9827
 F src/vdbeapi.c 2ba821c5929a2769e4b217dd85843479c718b8989d414723ec8af0616a83d611
@@ -1769,7 +1769,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 7edd26ed27ed1e7eab603058f7d55f2eac45e7bd1908bfa5f32293611883b157 5e458f4a92743effb9a3d3249767424fed8b444a05ca136c4a55d60c4d70c2cc
-R 6e3668e1a9453a68a64669c9f81648e7
+P 22ae8a52dd2fb744f467c7dccf1d7fe7c7cef0e1dcc897dd492f897e84c9facb
+R 33a3ccc9bec749141fe1417d8f2213ed
 U drh
-Z 479e3a8163395f3eaf4fbec67bf9b33f
+Z 4fef5bba9e51ca59b92e81f3a1e63e07
diff --git a/manifest.uuid b/manifest.uuid
index 782e07d0aa..9e827d388a 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-22ae8a52dd2fb744f467c7dccf1d7fe7c7cef0e1dcc897dd492f897e84c9facb
\ No newline at end of file
+d10e63629183f6daf0c263cd4dae052a3786c8c1480b3b6a73124b3315e41951
\ No newline at end of file
diff --git a/src/vdbe.c b/src/vdbe.c
index e57a197975..6a50fa2f99 100644
--- a/src/vdbe.c
+++ b/src/vdbe.c
@@ -2894,17 +2894,25 @@ case OP_MakeRecord: {
     if( nVarint<sqlite3VarintLen(nHdr) ) nHdr++;
   }
   nByte = nHdr+nData;
-  if( nByte+nZero>db->aLimit[SQLITE_LIMIT_LENGTH] ){
-    goto too_big;
-  }
 
   /* Make sure the output register has a buffer large enough to store 
   ** the new record. The output register (pOp->p3) is not allowed to
   ** be one of the input registers (because the following call to
   ** sqlite3VdbeMemClearAndResize() could clobber the value before it is used).
   */
-  if( sqlite3VdbeMemClearAndResize(pOut, (int)nByte) ){
-    goto no_mem;
+  if( nByte+nZero<=pOut->szMalloc ){
+    /* The output register is already large enough to hold the record.
+    ** No error checks or buffer enlargement is required */
+    pOut->z = pOut->zMalloc;
+  }else{
+    /* Need to make sure that the output is not too big and then enlarge
+    ** the output register to hold the full result */
+    if( nByte+nZero>db->aLimit[SQLITE_LIMIT_LENGTH] ){
+      goto too_big;
+    }
+    if( sqlite3VdbeMemClearAndResize(pOut, (int)nByte) ){
+      goto no_mem;
+    }
   }
   zNewRecord = (u8 *)pOut->z;