Index: src/pragma.c
==================================================================
--- src/pragma.c
+++ src/pragma.c
@@ -292,10 +292,18 @@
       lwr = mid + 1;
     }
   }
   return lwr>upr ? 0 : &aPragmaName[mid];
 }
+
+/*
+** A progress handler callback that interrupts.
+*/
+static int interruptProgressHandler(void *pDb){
+  sqlite3_interrupt((sqlite3*)pDb);
+  return 1;
+}
 
 /*
 ** Process a pragma statement.  
 **
 ** Pragmas are of this form:
@@ -733,10 +741,27 @@
     sqlite3VdbeAddOp2(v, OP_IfPos, 1, addr); VdbeCoverage(v);
     sqlite3VdbeJumpHere(v, addr);
     break;
   }
 #endif
+
+  /*
+  **  PRAGMA vdbe_cycle_limit=N
+  **
+  ** Arrange to interrupt any SQL statement that runs for more than N
+  ** virtual machine instructions.  If N is zero, allow virtual machines
+  ** to run indefinitely.
+  */
+  case PragTyp_VDBE_CYCLE_LIMIT: {
+    assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
+    if( zRight ){
+      int N = sqlite3Atoi(zRight);
+      sqlite3_progress_handler(db, N, N>0 ? interruptProgressHandler : 0, db);
+    }
+    break;
+  }
+
 
 #ifndef SQLITE_OMIT_PAGER_PRAGMAS
   /*
   **  PRAGMA [schema.]cache_size
   **  PRAGMA [schema.]cache_size=N

Index: src/pragma.h
==================================================================
--- src/pragma.h
+++ src/pragma.h
@@ -38,18 +38,19 @@
 #define PragTyp_SYNCHRONOUS                   30
 #define PragTyp_TABLE_INFO                    31
 #define PragTyp_TEMP_STORE                    32
 #define PragTyp_TEMP_STORE_DIRECTORY          33
 #define PragTyp_THREADS                       34
-#define PragTyp_WAL_AUTOCHECKPOINT            35
-#define PragTyp_WAL_CHECKPOINT                36
-#define PragTyp_ACTIVATE_EXTENSIONS           37
-#define PragTyp_HEXKEY                        38
-#define PragTyp_KEY                           39
-#define PragTyp_REKEY                         40
-#define PragTyp_LOCK_STATUS                   41
-#define PragTyp_PARSER_TRACE                  42
+#define PragTyp_VDBE_CYCLE_LIMIT              35
+#define PragTyp_WAL_AUTOCHECKPOINT            36
+#define PragTyp_WAL_CHECKPOINT                37
+#define PragTyp_ACTIVATE_EXTENSIONS           38
+#define PragTyp_HEXKEY                        39
+#define PragTyp_KEY                           40
+#define PragTyp_REKEY                         41
+#define PragTyp_LOCK_STATUS                   42
+#define PragTyp_PARSER_TRACE                  43
 
 /* Property flags associated with various pragma. */
 #define PragFlg_NeedSchema 0x01 /* Force schema load before running */
 #define PragFlg_NoColumns  0x02 /* OP_ResultRow called with zero columns */
 #define PragFlg_NoColumns1 0x04 /* zero columns if RHS argument is present */
@@ -560,10 +561,19 @@
  {/* zName:     */ "vdbe_addoptrace",
   /* ePragTyp:  */ PragTyp_FLAG,
   /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
   /* ColNames:  */ 0, 0,
   /* iArg:      */ SQLITE_VdbeAddopTrace },
+#endif
+#endif
+ {/* zName:     */ "vdbe_cycle_limit",
+  /* ePragTyp:  */ PragTyp_VDBE_CYCLE_LIMIT,
+  /* ePragFlg:  */ PragFlg_NoColumns,
+  /* ColNames:  */ 0, 0,
+  /* iArg:      */ 0 },
+#if !defined(SQLITE_OMIT_FLAG_PRAGMAS)
+#if defined(SQLITE_DEBUG)
  {/* zName:     */ "vdbe_debug",
   /* ePragTyp:  */ PragTyp_FLAG,
   /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
   /* ColNames:  */ 0, 0,
   /* iArg:      */ SQLITE_SqlTrace|SQLITE_VdbeListing|SQLITE_VdbeTrace },
@@ -602,6 +612,6 @@
   /* ePragFlg:  */ PragFlg_Result0|PragFlg_NoColumns1,
   /* ColNames:  */ 0, 0,
   /* iArg:      */ SQLITE_WriteSchema|SQLITE_RecoveryMode },
 #endif
 };
-/* Number of pragmas: 60 on by default, 73 total. */
+/* Number of pragmas: 61 on by default, 74 total. */

Index: tool/mkpragmatab.tcl
==================================================================
--- tool/mkpragmatab.tcl
+++ tool/mkpragmatab.tcl
@@ -328,10 +328,13 @@
   NAME: wal_autocheckpoint
   IF:   !defined(SQLITE_OMIT_WAL)
 
   NAME: shrink_memory
   FLAG: NoColumns
+
+  NAME: vdbe_cycle_limit
+  FLAG: NoColumns
 
   NAME: busy_timeout
   FLAG: Result0
   COLS: timeout