Add a HIGHSTRESS parameter to the sqlite3_config_alt_pcache debugging

command in the test harness - to force calling pagerStress() more
frequently. (CVS 6127)

FossilOrigin-Name: e426860b94f5b47e3a265549dbac64a421cae425

2 files changed, 34 insertions, 12 deletions

diff --git a/src/test_malloc.c b/src/test_malloc.c
index 2009f5428..7519b5f7a 100644
--- a/src/test_malloc.c
+++ b/src/test_malloc.c
@@ -13,7 +13,7 @@
 ** This file contains code used to implement test interfaces to the
 ** memory allocation subsystem.
 **
-** $Id: test_malloc.c,v 1.51 2008/11/19 01:20:26 drh Exp $
+** $Id: test_malloc.c,v 1.52 2009/01/07 03:59:47 drh Exp $
 */
 #include "sqliteInt.h"
 #include "tcl.h"
@@ -962,22 +962,32 @@ static int test_alt_pcache(
   Tcl_Obj *CONST objv[]
 ){
   int installFlag;
-  int discardChance;
-  int prngSeed;
-  extern void installTestPCache(int,unsigned,unsigned);
-  if( objc!=4 ){
-    Tcl_WrongNumArgs(interp, 1, objv, "INSTALLFLAG DISCARDCHANCE PRNGSEEED");
+  int discardChance = 0;
+  int prngSeed = 0;
+  int highStress = 0;
+  extern void installTestPCache(int,unsigned,unsigned,unsigned);
+  if( objc<2 || objc>5 ){
+    Tcl_WrongNumArgs(interp, 1, objv, 
+        "INSTALLFLAG DISCARDCHANCE PRNGSEEED HIGHSTRESS");
     return TCL_ERROR;
   }
   if( Tcl_GetIntFromObj(interp, objv[1], &installFlag) ) return TCL_ERROR;
-  if( Tcl_GetIntFromObj(interp, objv[2], &discardChance) ) return TCL_ERROR;
-  if( Tcl_GetIntFromObj(interp, objv[3], &prngSeed) ) return TCL_ERROR;
+  if( objc>=3 && Tcl_GetIntFromObj(interp, objv[2], &discardChance) ){
+     return TCL_ERROR;
+  }
+  if( objc>=4 && Tcl_GetIntFromObj(interp, objv[3], &prngSeed) ){
+     return TCL_ERROR;
+  }
+  if( objc>=5 && Tcl_GetIntFromObj(interp, objv[4], &highStress) ){
+    return TCL_ERROR;
+  }
   if( discardChance<0 || discardChance>100 ){
     Tcl_AppendResult(interp, "discard-chance should be between 0 and 100",
                      (char*)0);
     return TCL_ERROR;
   }
-  installTestPCache(installFlag, (unsigned)discardChance, (unsigned)prngSeed);
+  installTestPCache(installFlag, (unsigned)discardChance, (unsigned)prngSeed,
+                    (unsigned)highStress);
   return TCL_OK;
 }
 
diff --git a/src/test_pcache.c b/src/test_pcache.c
index 58f5b3981..05bc8f7e4 100644
--- a/src/test_pcache.c
+++ b/src/test_pcache.c
@@ -21,7 +21,7 @@
 ** This pagecache implementation is designed for simplicity
 ** not speed.  
 **
-** $Id: test_pcache.c,v 1.1 2008/11/19 01:20:26 drh Exp $
+** $Id: test_pcache.c,v 1.2 2009/01/07 03:59:47 drh Exp $
 */
 #include "sqlite3.h"
 #include <string.h>
@@ -36,8 +36,9 @@ typedef struct testpcacheGlobalType testpcacheGlobalType;
 struct testpcacheGlobalType {
   void *pDummy;             /* Dummy allocation to simulate failures */
   int nInstance;            /* Number of current instances */
-  unsigned discardChance;   /* Chance of discarding on an unpin */
+  unsigned discardChance;   /* Chance of discarding on an unpin (0-100) */
   unsigned prngSeed;        /* Seed for the PRNG */
+  unsigned highStress;      /* Call xStress agressively */
 };
 static testpcacheGlobalType testpcacheGlobal;
 
@@ -210,6 +211,15 @@ static void *testpcacheFetch(
     return 0;
   }
 
+  /* Do not allocate if highStress is enabled and createFlag is not 2.  
+  **
+  ** The highStress setting causes pagerStress() to be called much more
+  ** often, which exercises the pager logic more intensely.
+  */
+  if( testpcacheGlobal.highStress && createFlag<2 ){
+    return 0;
+  }
+
   /* Find a free page to allocate if there are any free pages.
   ** Withhold TESTPCACHE_RESERVE free pages until createFlag is 2.
   */
@@ -401,7 +411,8 @@ static void testpcacheDestroy(sqlite3_pcache *pCache){
 void installTestPCache(
   int installFlag,            /* True to install.  False to uninstall. */
   unsigned discardChance,     /* 0-100.  Chance to discard on unpin */
-  unsigned prngSeed           /* Seed for the PRNG */
+  unsigned prngSeed,          /* Seed for the PRNG */
+  unsigned highStress         /* Call xStress agressively */
 ){
   static const sqlite3_pcache_methods testPcache = {
     (void*)&testpcacheGlobal,
@@ -424,6 +435,7 @@ void installTestPCache(
   assert( discardChance<=100 );
   testpcacheGlobal.discardChance = discardChance;
   testpcacheGlobal.prngSeed = prngSeed ^ (prngSeed<<16);
+  testpcacheGlobal.highStress = highStress;
   if( installFlag!=isInstalled ){
     if( installFlag ){
       sqlite3_config(SQLITE_CONFIG_GETPCACHE, &defaultPcache);