Avoid unnecessary zeroing of fields in the Vdbe object when it is allocated.

FossilOrigin-Name: 1e21bbe836539e64d24857f4faa3d12cd607dc7e

manifest

@@ -1,5 +1,5 @@
-C Avoid\sinitializing\sthe\scolumn-cache\ssection\sof\sthe\sParse\sobject,\ssince\sentries\nin\sthe\scache\swill\sbe\sinitialized\sas\sthey\sare\sused,\sand\savoiding\sthe\sinitial\nmemset()\ssaves\smany\sCPU\scycles.
-D 2016-09-30T22:24:29.959
+C Avoid\sunnecessary\szeroing\sof\sfields\sin\sthe\sVdbe\sobject\swhen\sit\sis\sallocated.
+D 2016-10-01T00:37:50.922
 F Makefile.in 6fd48ffcf7c2deea7499062d1f3747f986c19678
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc 5151cc64c4c05f3455f4f692ad11410a810d937f
@@ -455,9 +455,9 @@ F src/util.c 3e2da6101888d073e79ecc6af5e0a2f70fa1e498
 F src/vacuum.c 913970b9d86dd6c2b8063ef1af421880f1464ec3
 F src/vdbe.c 51e754eec26d892abc6279f5e949545af68ec1b3
 F src/vdbe.h c044be7050ac6bf596eecc6ab159f5dbc020a3b7
-F src/vdbeInt.h 581b737c2f6e413c555469480efe31796a71bcad
+F src/vdbeInt.h 0a18713d0a2fec6807d076bd333d9bf3e57530cd
 F src/vdbeapi.c 794f80669e9e3b9b3edc78d80c15968985c7bf21
-F src/vdbeaux.c 5f97a1aed18b5b064407652654f73f3cd4836a87
+F src/vdbeaux.c 4c0678a2a2c315534a2609de515d04cccf3990fb
 F src/vdbeblob.c 3e82a797b60c3b9fed7b8de8c539ca7607874937
 F src/vdbemem.c 1c330522e6b6e4ddd2ff63c4c0dfafa20c3965a7
 F src/vdbesort.c 91fda3909326860382b0ca8aa251e609c6a9d62c
@@ -1525,7 +1525,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P ab12fce3318db447995e1465f34a1e43cd623d6a
-R 0a3a2f22297400a0c501bf7a0c2b0caa
+P 63cf7eafae5c3c1379edf416c5157010c7c120b5
+R 85f9a9479e2ad57a2952b90cd8e20395
 U drh
-Z fb861c120dabfe63359c1b99efc6b84b
+Z e3416eaec67cf3f8ba5f96a2088d495d

manifest.uuid

@@ -1 +1 @@
-63cf7eafae5c3c1379edf416c5157010c7c120b5
+1e21bbe836539e64d24857f4faa3d12cd607dc7e

src/vdbeInt.h

@@ -340,34 +340,47 @@ struct ScanStatus {
 */
 struct Vdbe {
   sqlite3 *db;            /* The database connection that owns this statement */
+  Vdbe *pPrev,*pNext;     /* Linked list of VDBEs with the same Vdbe.db */
+  Parse *pParse;          /* Parsing context used to create this Vdbe */
+  ynVar nVar;             /* Number of entries in aVar[] */
+  ynVar nzVar;            /* Number of entries in azVar[] */
+  u32 magic;              /* Magic number for sanity checking */
+  int nMem;               /* Number of memory locations currently allocated */
+  int nCursor;            /* Number of slots in apCsr[] */
+  u32 cacheCtr;           /* VdbeCursor row cache generation counter */
+  int pc;                 /* The program counter */
+  int rc;                 /* Value to return */
+  int nChange;            /* Number of db changes made since last reset */
+  int iStatement;         /* Statement number (or 0 if has not opened stmt) */
+  i64 iCurrentTime;       /* Value of julianday('now') for this statement */
+  i64 nFkConstraint;      /* Number of imm. FK constraints this VM */
+  i64 nStmtDefCons;       /* Number of def. constraints when stmt started */
+  i64 nStmtDefImmCons;    /* Number of def. imm constraints when stmt started */
+
+  /* When allocating a new Vdbe object, all of the fields below should be
+  ** initialized to zero or NULL */
+
   Op *aOp;                /* Space to hold the virtual machine's program */
   Mem *aMem;              /* The memory locations */
   Mem **apArg;            /* Arguments to currently executing user function */
   Mem *aColName;          /* Column names to return */
   Mem *pResultSet;        /* Pointer to an array of results */
-  Parse *pParse;          /* Parsing context used to create this Vdbe */
-  int nMem;               /* Number of memory locations currently allocated */
-  int nOp;                /* Number of instructions in the program */
-  int nCursor;            /* Number of slots in apCsr[] */
-  u32 magic;              /* Magic number for sanity checking */
   char *zErrMsg;          /* Error message written here */
-  Vdbe *pPrev,*pNext;     /* Linked list of VDBEs with the same Vdbe.db */
   VdbeCursor **apCsr;     /* One element of this array for each open cursor */
   Mem *aVar;              /* Values for the OP_Variable opcode. */
   char **azVar;           /* Name of variables */
-  ynVar nVar;             /* Number of entries in aVar[] */
-  ynVar nzVar;            /* Number of entries in azVar[] */
-  u32 cacheCtr;           /* VdbeCursor row cache generation counter */
-  int pc;                 /* The program counter */
-  int rc;                 /* Value to return */
+#ifndef SQLITE_OMIT_TRACE
+  i64 startTime;          /* Time when query started - used for profiling */
+#endif
+  int nOp;                /* Number of instructions in the program */
 #ifdef SQLITE_DEBUG
   int rcApp;              /* errcode set by sqlite3_result_error_code() */
 #endif
   u16 nResColumn;         /* Number of columns in one row of the result set */
   u8 errorAction;         /* Recovery action to do in case of an error */
+  u8 minWriteFileFormat;  /* Minimum file format for writable database files */
   bft expired:1;          /* True if the VM needs to be recompiled */
   bft doingRerun:1;       /* True if rerunning after an auto-reprepare */
-  u8 minWriteFileFormat;  /* Minimum file format for writable database files */
   bft explain:2;          /* True if EXPLAIN present on SQL command */
   bft changeCntOn:1;      /* True to update the change-counter */
   bft runOnlyOnce:1;      /* Automatically expire on reset */
@@ -375,18 +388,9 @@ struct Vdbe {
   bft readOnly:1;         /* True for statements that do not write */
   bft bIsReader:1;        /* True for statements that read */
   bft isPrepareV2:1;      /* True if prepared with prepare_v2() */
-  int nChange;            /* Number of db changes made since last reset */
   yDbMask btreeMask;      /* Bitmask of db->aDb[] entries referenced */
   yDbMask lockMask;       /* Subset of btreeMask that requires a lock */
-  int iStatement;         /* Statement number (or 0 if has not opened stmt) */
   u32 aCounter[5];        /* Counters used by sqlite3_stmt_status() */
-#ifndef SQLITE_OMIT_TRACE
-  i64 startTime;          /* Time when query started - used for profiling */
-#endif
-  i64 iCurrentTime;       /* Value of julianday('now') for this statement */
-  i64 nFkConstraint;      /* Number of imm. FK constraints this VM */
-  i64 nStmtDefCons;       /* Number of def. constraints when stmt started */
-  i64 nStmtDefImmCons;    /* Number of def. imm constraints when stmt started */
   char *zSql;             /* Text of the SQL statement that generated this */
   void *pFree;            /* Free this when deleting the vdbe */
   VdbeFrame *pFrame;      /* Parent frame */
@@ -405,10 +409,11 @@ struct Vdbe {
 /*
 ** The following are allowed values for Vdbe.magic
 */
-#define VDBE_MAGIC_INIT     0x26bceaa5    /* Building a VDBE program */
-#define VDBE_MAGIC_RUN      0xbdf20da3    /* VDBE is ready to execute */
-#define VDBE_MAGIC_HALT     0x519c2973    /* VDBE has completed execution */
-#define VDBE_MAGIC_DEAD     0xb606c3c8    /* The VDBE has been deallocated */
+#define VDBE_MAGIC_INIT     0x16bceaa5    /* Building a VDBE program */
+#define VDBE_MAGIC_RUN      0x2df20da3    /* VDBE is ready to execute */
+#define VDBE_MAGIC_HALT     0x319c2973    /* VDBE has completed execution */
+#define VDBE_MAGIC_RESET    0x48fa9f76    /* Reset and ready to run again */
+#define VDBE_MAGIC_DEAD     0x5606c3c8    /* The VDBE has been deallocated */
 
 /*
 ** Structure used to store the context required by the 

src/vdbeaux.c

@@ -21,8 +21,9 @@
 Vdbe *sqlite3VdbeCreate(Parse *pParse){
   sqlite3 *db = pParse->db;
   Vdbe *p;
-  p = sqlite3DbMallocZero(db, sizeof(Vdbe) );
+  p = sqlite3DbMallocRaw(db, sizeof(Vdbe) );
   if( p==0 ) return 0;
+  memset(&p->aOp, 0, sizeof(Vdbe)-offsetof(Vdbe,aOp));
   p->db = db;
   if( db->pVdbe ){
     db->pVdbe->pPrev = p;
@@ -1826,7 +1827,7 @@ void sqlite3VdbeRewind(Vdbe *p){
   int i;
 #endif
   assert( p!=0 );
-  assert( p->magic==VDBE_MAGIC_INIT );
+  assert( p->magic==VDBE_MAGIC_INIT || p->magic==VDBE_MAGIC_RESET );
 
   /* There should be at least one opcode.
   */
@@ -1953,7 +1954,11 @@ void sqlite3VdbeMakeReady(
   pParse->nzVar =  0;
   pParse->azVar = 0;
   p->explain = pParse->explain;
-  if( db->mallocFailed==0 ){
+  if( db->mallocFailed ){
+    p->nVar = 0;
+    p->nCursor = 0;
+    p->nMem = 0;
+  }else{
     p->nCursor = nCursor;
     p->nVar = (ynVar)nVar;
     initMemArray(p->aVar, nVar, db, MEM_Null);
@@ -2880,7 +2885,7 @@ int sqlite3VdbeReset(Vdbe *p){
   }
 #endif
   p->iCurrentTime = 0;
-  p->magic = VDBE_MAGIC_INIT;
+  p->magic = VDBE_MAGIC_RESET;
   return p->rc & db->errMask;
 }
  
@@ -2951,7 +2956,9 @@ void sqlite3VdbeClearObject(sqlite3 *db, Vdbe *p){
     vdbeFreeOpArray(db, pSub->aOp, pSub->nOp);
     sqlite3DbFree(db, pSub);
   }
-  for(i=p->nzVar-1; i>=0; i--) sqlite3DbFree(db, p->azVar[i]);
+  if( p->magic!=VDBE_MAGIC_INIT ){
+    for(i=p->nzVar-1; i>=0; i--) sqlite3DbFree(db, p->azVar[i]);
+  }
   sqlite3DbFree(db, p->azVar);
   vdbeFreeOpArray(db, p->aOp, p->nOp);
   sqlite3DbFree(db, p->aColName);