Add the SQLITE_DB_STATUS_CACHE_HIT and MISS options. For querying the number of cache hits and misses on a per-connection basis.

FossilOrigin-Name: 5100b6e9dc5107f0f835d0aac26fe6d4938ffc73

manifest

@@ -1,5 +1,5 @@
-C Update\sthe\sversion\snumber\sto\s3.7.9.
+C Add\sthe\sSQLITE_DB_STATUS_CACHE_HIT\sand\sMISS\soptions.\sFor\squerying\sthe\snumber\sof\scache\shits\sand\smisses\son\sa\sper-connection\sbasis.
-D 2011-09-22T00:56:38.282
+D 2011-09-22T14:41:16.523
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in 8de00a4e52f308ef6d564834c0973e53646e0d4c
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -167,8 +167,8 @@ F src/os_common.h 92815ed65f805560b66166e3583470ff94478f04
 F src/os_os2.c 4a75888ba3dfc820ad5e8177025972d74d7f2440
 F src/os_unix.c 10e0c4dcdbec8d4189890fdf3e71b32efae194e3
 F src/os_win.c 0fc0f46c94b0385a940b0ee32992a833019a5985
-F src/pager.c 15d10371e2d560b68870a9ccec022ad8f01e70a2
+F src/pager.c 8a6ac3e0d9694412076e2273e3c81e9c4e08758f
-F src/pager.h 3f8c783de1d4706b40b1ac15b64f5f896bcc78d1
+F src/pager.h dbcaa791e8b6c3a6b77c168c5c27deec289fb176
 F src/parse.y 12b7ebd61ea54f0e1b1083ff69cc2c8ce9353d58
 F src/pcache.c 49e718c095810c6b3334e3a6d89970aceaddefce
 F src/pcache.h c683390d50f856d4cd8e24342ae62027d1bb6050
@@ -181,11 +181,11 @@ F src/resolve.c 36368f44569208fa074e61f4dd0b6c4fb60ca2b4
 F src/rowset.c 69afa95a97c524ba6faf3805e717b5b7ae85a697
 F src/select.c d9b7d20b0365f80761846f00ef3638d4b33eeaf2
 F src/shell.c 13fe2aeddc3cc90d6a273831d1f63736d1596f81
-F src/sqlite.h.in 0a6c9c23337fd1352c5c75a613ff9533aa7d91cb
+F src/sqlite.h.in c0ebc53056fd99590dec4cb4bd60a0787098ff18
 F src/sqlite3ext.h 1a1a4f784aa9c3b00edd287940197de52487cd93
 F src/sqliteInt.h 76d81cd9da0618b231398bfcf90556e971972fca
 F src/sqliteLimit.h 164b0e6749d31e0daa1a4589a169d31c0dec7b3d
-F src/status.c 7ac64842c86cec2fc1a1d0e5c16d3beb8ad332bf
+F src/status.c 4568e72dfd36b6a5911f93457364deb072e0b03a
 F src/table.c 2cd62736f845d82200acfa1287e33feb3c15d62e
 F src/tclsqlite.c 20578e66dda94b4d4db3d4478644a4dd9c6084a6
 F src/test1.c 0f41b7c67719207a5de24b009e172c4dcf189827
@@ -212,7 +212,7 @@ F src/test_intarray.c d879bbf8e4ce085ab966d1f3c896a7c8b4f5fc99
 F src/test_intarray.h 489edb9068bb926583445cb02589344961054207
 F src/test_journal.c 03313c693cca72959dcaaf79f8d76f21c01e19ff
 F src/test_loadext.c df586c27176e3c2cb2e099c78da67bf14379a56e
-F src/test_malloc.c 91d5cf1751d3e563754fd183da1c020727b5480e
+F src/test_malloc.c 8d416f29ad8573f32601f6056c9d2b17472e9ad5
 F src/test_multiplex.c 3fc368022c46fe44ec22c5e1ed727223a54a6a1d
 F src/test_multiplex.h e99c571bc4968b7a9363b661481f3934bfead61d
 F src/test_mutex.c a6bd7b9cf6e19d989e31392b06ac8d189f0d573e
@@ -361,6 +361,7 @@ F test/cse.test 277350a26264495e86b1785f34d2d0c8600e021c
 F test/ctime.test 7f0bd5084d9dd7da9ad46901810896edd2ebb463
 F test/date.test a18a2ce81add84b17b06559e82ad7bb91bc6ddff
 F test/dbstatus.test a719af0f226bd280748a4bb9054c0a5a9fc1b16c
+F test/dbstatus2.test dc57b0d9610851c0ff58a8e1b5b191678398b72a
 F test/default.test 6faf23ccb300114924353007795aa9a8ec0aa9dc
 F test/delete.test a065b05d2ebf60fd16639c579a4adfb7c381c701
 F test/delete2.test 3a03f2cca1f9a67ec469915cb8babd6485db43fa
@@ -963,7 +964,7 @@ F tool/symbols.sh caaf6ccc7300fd43353318b44524853e222557d5
 F tool/tostr.awk e75472c2f98dd76e06b8c9c1367f4ab07e122d06
 F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
 F tool/warnings.sh b7fdb2cc525f5ef4fa43c80e771636dd3690f9d2
-P af1c5718292c0326b785416b7109eafefaeb59a7
+P 14e28eb9546906b33eb03e596ad104c8ca049d6c
-R 683508422a28a1700de71635798902cb
+R 9879b749e51ddd30db2e7953d801cb26
-U drh
+U dan
-Z fbf5cbfa4acf8c5482bae2d6dc544add
+Z f68e24447a093110c356752c29a0f88a

manifest.uuid

@@ -1 +1 @@
-14e28eb9546906b33eb03e596ad104c8ca049d6c
+5100b6e9dc5107f0f835d0aac26fe6d4938ffc73

src/pager.c

@@ -670,8 +670,8 @@ struct Pager {
   char *zJournal;             /* Name of the journal file */
   int (*xBusyHandler)(void*); /* Function to call when busy */
   void *pBusyHandlerArg;      /* Context argument for xBusyHandler */
+  int nHit, nMiss;            /* Total cache hits and misses */
 #ifdef SQLITE_TEST
-  int nHit, nMiss;            /* Cache hits and missing */
   int nRead, nWrite;          /* Database pages read/written */
 #endif
   void (*xReiniter)(DbPage*); /* Call this routine when reloading pages */
@@ -4169,7 +4169,7 @@ static int pagerStress(void *p, PgHdr *pPg){
   **
   ** Spilling is also prohibited when in an error state since that could
   ** lead to database corruption.   In the current implementaton it 
-  ** is impossible for sqlite3PCacheFetch() to be called with createFlag==1
+  ** is impossible for sqlite3PcacheFetch() to be called with createFlag==1
   ** while in the error state, hence it is impossible for this routine to
   ** be called in the error state.  Nevertheless, we include a NEVER()
   ** test for the error state as a safeguard against future changes.
@@ -5005,14 +5005,13 @@ int sqlite3PagerAcquire(
     /* In this case the pcache already contains an initialized copy of
     ** the page. Return without further ado.  */
     assert( pgno<=PAGER_MAX_PGNO && pgno!=PAGER_MJ_PGNO(pPager) );
-    PAGER_INCR(pPager->nHit);
+    pPager->nHit++;
     return SQLITE_OK;
 
   }else{
     /* The pager cache has created a new page. Its content needs to 
     ** be initialized.  */
 
-    PAGER_INCR(pPager->nMiss);
     pPg = *ppPage;
     pPg->pPager = pPager;
 
@@ -5048,6 +5047,7 @@ int sqlite3PagerAcquire(
       IOTRACE(("ZERO %p %d\n", pPager, pgno));
     }else{
       assert( pPg->pPager==pPager );
+      pPager->nMiss++;
       rc = readDbPage(pPg);
       if( rc!=SQLITE_OK ){
         goto pager_acquire_err;
@@ -6082,6 +6082,31 @@ int *sqlite3PagerStats(Pager *pPager){
 }
 #endif
 
+/*
+** Parameter eStat must be either SQLITE_DBSTATUS_CACHE_HIT or
+** SQLITE_DBSTATUS_CACHE_MISS. Before returning, *pnVal is incremented by the
+** current cache hit or miss count, according to the value of eStat. If the 
+** reset parameter is non-zero, the cache hit or miss count is zeroed before 
+** returning.
+*/
+void sqlite3PagerCacheStat(Pager *pPager, int eStat, int reset, int *pnVal){
+  int *piStat;
+
+  assert( eStat==SQLITE_DBSTATUS_CACHE_HIT
+       || eStat==SQLITE_DBSTATUS_CACHE_MISS
+  );
+  if( eStat==SQLITE_DBSTATUS_CACHE_HIT ){
+    piStat = &pPager->nHit;
+  }else{
+    piStat = &pPager->nMiss;
+  }
+
+  *pnVal += *piStat;
+  if( reset ){
+    *piStat = 0;
+  }
+}
+
 /*
 ** Return true if this is an in-memory pager.
 */

src/pager.h

@@ -155,6 +155,7 @@ const char *sqlite3PagerJournalname(Pager*);
 int sqlite3PagerNosync(Pager*);
 void *sqlite3PagerTempSpace(Pager*);
 int sqlite3PagerIsMemdb(Pager*);
+void sqlite3PagerCacheStat(Pager *, int, int, int *);
 
 /* Functions used to truncate the database file. */
 void sqlite3PagerTruncateImage(Pager*,Pgno);

src/sqlite.h.in

@@ -5810,6 +5810,18 @@ int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
 ** the database connection.)^
 ** ^The highwater mark associated with SQLITE_DBSTATUS_STMT_USED is always 0.
 ** </dd>
+**
+** [[SQLITE_DBSTATUS_CACHE_HIT]] ^(<dt>SQLITE_DBSTATUS_CACHE_HIT</dt>
+** <dd>This parameter returns the number of pager cache hits that have
+** occurred. ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_HIT 
+** is always 0.
+** </dd>
+**
+** [[SQLITE_DBSTATUS_CACHE_MISS]] ^(<dt>SQLITE_DBSTATUS_CACHE_MISS</dt>
+** <dd>This parameter returns the number of pager cache misses that have
+** occurred. ^The highwater mark associated with SQLITE_DBSTATUS_CACHE_MISS 
+** is always 0.
+** </dd>
 ** </dl>
 */
 #define SQLITE_DBSTATUS_LOOKASIDE_USED       0
@@ -5819,7 +5831,9 @@ int sqlite3_db_status(sqlite3*, int op, int *pCur, int *pHiwtr, int resetFlg);
 #define SQLITE_DBSTATUS_LOOKASIDE_HIT        4
 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE  5
 #define SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL  6
-#define SQLITE_DBSTATUS_MAX                  6   /* Largest defined DBSTATUS */
+#define SQLITE_DBSTATUS_CACHE_HIT            7
+#define SQLITE_DBSTATUS_CACHE_MISS           8
+#define SQLITE_DBSTATUS_MAX                  8   /* Largest defined DBSTATUS */
 
 
 /*
@@ -5873,7 +5887,6 @@ int sqlite3_stmt_status(sqlite3_stmt*, int op,int resetFlg);
 ** A non-zero value in this counter may indicate an opportunity to
 ** improvement performance by adding permanent indices that do not
 ** need to be reinitialized each time the statement is run.</dd>
-**
 ** </dl>
 */
 #define SQLITE_STMTSTATUS_FULLSCAN_STEP     1

src/status.c

@@ -218,6 +218,28 @@ int sqlite3_db_status(
       break;
     }
 
+    /*
+    ** Set *pCurrent to the total cache hits or misses encountered by all
+    ** pagers the database handle is connected to. *pHighwater is always set 
+    ** to zero.
+    */
+    case SQLITE_DBSTATUS_CACHE_HIT:
+    case SQLITE_DBSTATUS_CACHE_MISS: {
+      int i;
+      int nRet = 0;
+      assert( SQLITE_DBSTATUS_CACHE_MISS==SQLITE_DBSTATUS_CACHE_HIT+1 );
+
+      for(i=0; i<db->nDb; i++){
+        if( db->aDb[i].pBt ){
+          Pager *pPager = sqlite3BtreePager(db->aDb[i].pBt);
+          sqlite3PagerCacheStat(pPager, op, resetFlag, &nRet);
+        }
+      }
+      *pHighwater = 0;
+      *pCurrent = nRet;
+      break;
+    }
+
     default: {
       rc = SQLITE_ERROR;
     }

src/test_malloc.c

@@ -1325,11 +1325,13 @@ static int test_db_status(
     { "STMT_USED",           SQLITE_DBSTATUS_STMT_USED           },
     { "LOOKASIDE_HIT",       SQLITE_DBSTATUS_LOOKASIDE_HIT       },
     { "LOOKASIDE_MISS_SIZE", SQLITE_DBSTATUS_LOOKASIDE_MISS_SIZE },
-    { "LOOKASIDE_MISS_FULL", SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL }
+    { "LOOKASIDE_MISS_FULL", SQLITE_DBSTATUS_LOOKASIDE_MISS_FULL },
+    { "CACHE_HIT",           SQLITE_DBSTATUS_CACHE_HIT           },
+    { "CACHE_MISS",          SQLITE_DBSTATUS_CACHE_MISS          }
   };
   Tcl_Obj *pResult;
   if( objc!=4 ){
-    Tcl_WrongNumArgs(interp, 1, objv, "PARAMETER RESETFLAG");
+    Tcl_WrongNumArgs(interp, 1, objv, "DB PARAMETER RESETFLAG");
     return TCL_ERROR;
   }
   if( getDbPointer(interp, Tcl_GetString(objv[1]), &db) ) return TCL_ERROR;

test/dbstatus2.test

@@ -0,0 +1,76 @@
+# 2011 September 20
+#
+# The author disclaims copyright to this source code.  In place of
+# a legal notice, here is a blessing:
+#
+#    May you do good and not evil.
+#    May you find forgiveness for yourself and forgive others.
+#    May you share freely, never taking more than you give.
+#
+#***********************************************************************
+#
+# Tests for the sqlite3_stmt_status() function
+#
+
+set testdir [file dirname $argv0]
+source $testdir/tester.tcl
+
+set ::testprefix dbstatus2
+
+do_execsql_test 1.0 {
+  PRAGMA page_size = 1024;
+  PRAGMA auto_vacuum = 0;
+
+  CREATE TABLE t1(a PRIMARY KEY, b);
+  INSERT INTO t1 VALUES(1, randomblob(600));
+  INSERT INTO t1 VALUES(2, randomblob(600));
+  INSERT INTO t1 VALUES(3, randomblob(600));
+}
+
+proc db_hit_miss {db {reset 0}} {
+  set nHit  [sqlite3_db_status $db CACHE_HIT $reset]
+  set nMiss [sqlite3_db_status $db CACHE_MISS $reset]
+  list $nHit $nMiss
+}
+
+do_test 1.1 {
+  db close
+  sqlite3 db test.db
+  expr {[file size test.db] / 1024}
+} 6
+
+do_test 1.2 {
+  execsql { SELECT b FROM t1 WHERE a=2 }
+  db_hit_miss db
+} {{0 2 0} {0 4 0}}
+
+do_test 1.3 { 
+  execsql { SELECT b FROM t1 WHERE a=2 }
+  db_hit_miss db
+} {{0 6 0} {0 4 0}}
+
+do_test 1.4 { 
+  execsql { SELECT b FROM t1 WHERE a=2 }
+  db_hit_miss db
+} {{0 10 0} {0 4 0}}
+
+do_test 1.5 { 
+  db_hit_miss db 1
+} {{0 10 0} {0 4 0}}
+
+do_test 1.6 { 
+  db_hit_miss db 0
+} {{0 0 0} {0 0 0}}
+
+do_test 1.7 {
+  set fd [db incrblob main t1 b 1]
+  fconfigure $fd -translation binary
+  set len [string length [read $fd]]
+  close $fd
+  set len
+} 600
+do_test 1.8 { sqlite3_db_status db CACHE_HIT  0 } {0 2 0}
+do_test 1.9 { sqlite3_db_status db CACHE_MISS 0 } {0 1 0}
+
+ 
+finish_test