SQLite

**
** This file implements the default page cache implementation (the
** sqlite3_pcache interface). It also contains part of the implementation
** of the SQLITE_CONFIG_PAGECACHE and sqlite3_release_memory() features.
** If the default page cache implementation is overriden, then neither of
** these two features are available.
**
** @(#) $Id: pcache1.c,v 1.11.2.1 2009/05/18 16:14:25 drh Exp $
*/

#include "sqliteInt.h"

typedef struct PCache1 PCache1;
typedef struct PgHdr1 PgHdr1;
typedef struct PgFreeslot PgFreeslot;

**
** The global mutex must be held when this function is called.
*/
static void pcache1TruncateUnsafe(
  PCache1 *pCache, 
  unsigned int iLimit 
){
  TESTONLY( int nPage = 0; )      /* Used to assert pCache->nPage is correct */
  unsigned int h;
  assert( sqlite3_mutex_held(pcache1.mutex) );
  for(h=0; h<pCache->nHash; h++){
    PgHdr1 **pp = &pCache->apHash[h]; 
    PgHdr1 *pPage;
    while( (pPage = *pp)!=0 ){
      if( pPage->iKey>=iLimit ){
        pCache->nPage--;
        *pp = pPage->pNext;
        pcache1PinPage(pPage);
        pcache1FreePage(pPage);
      }else{
        pp = &pPage->pNext;
        TESTONLY( nPage++ );
      }
    }
  }
  assert( pCache->nPage==nPage );
}

/******************************************************************************/
/******** sqlite3_pcache Methods **********************************************/

/*
** Implementation of the sqlite3_pcache.xInit method.

**
** Various scripts scan this source file in order to generate HTML
** documentation, headers files, or other derived files.  The formatting
** of the code in this file is, therefore, important.  See other comments
** in this file for details.  If in doubt, do not deviate from existing
** commenting and indentation practices when changing or adding code.
**
** $Id: vdbe.c,v 1.842.2.1 2009/05/18 16:14:25 drh Exp $
*/
#include "sqliteInt.h"
#include "vdbeInt.h"

/*
** The following global variable is incremented every time a cursor
** moves, either by the OP_SeekXX, OP_Next, or OP_Prev opcodes.  The test

    opProperty = opcodeProperty[pOp->opcode];
    if( (opProperty & OPFLG_OUT2_PRERELEASE)!=0 ){
      assert( pOp->p2>0 );
      assert( pOp->p2<=p->nMem );
      pOut = &p->aMem[pOp->p2];
      sqlite3VdbeMemReleaseExternal(pOut);
      pOut->flags = MEM_Null;
      pOut->n = 0;
    }else
 
    /* Do common setup for opcodes marked with one of the following
    ** combinations of properties.
    **
    **           in1
    **           in1 in2

# 2008 August 29
#
# 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.
#
#***********************************************************************
#
# This file is focused on testing the pcache module.
#
# $Id: pcache.test,v 1.4.2.1 2009/05/18 16:14:26 drh Exp $

set testdir [file dirname $argv0]
source $testdir/tester.tcl


# The pcache module limits the number of pages available to purgeable
# caches to the sum of the 'cache_size' values for the set of open

} {current 19 max 20 min 10 recyclable 19}

do_test pcache-1.13 {
  execsql { PRAGMA cache_size = 15 }
  pcache_stats
} {current 15 max 15 min 10 recyclable 15}

do_test pcache-1.14 {
  hexio_write test.db 24 [hexio_render_int32 1000]
  execsql { SELECT * FROM sqlite_master }
  pcache_stats
} {current 2 max 15 min 10 recyclable 2}

do_test pcache-1.15 {
  execsql { 
    SELECT * FROM t1 ORDER BY a; SELECT * FROM t1;
    SELECT * FROM t2 ORDER BY a; SELECT * FROM t2;
    SELECT * FROM t3 ORDER BY a; SELECT * FROM t3;
    SELECT * FROM t4 ORDER BY a; SELECT * FROM t4;
    SELECT * FROM t5 ORDER BY a; SELECT * FROM t5;
    SELECT * FROM t6 ORDER BY a; SELECT * FROM t6;
    SELECT * FROM t7 ORDER BY a; SELECT * FROM t7;
    SELECT * FROM t8 ORDER BY a; SELECT * FROM t8;
    SELECT * FROM t9 ORDER BY a; SELECT * FROM t9;
  }
  pcache_stats
} {current 14 max 15 min 10 recyclable 14}

finish_test

#
# The ORDER BY would be dropped by the query flattener.  This used
# to not matter because aggregate functions sum(), min(), max(), avg(),
# and so forth give the same result regardless of the order of inputs.
# But with the addition of the group_concat() function, suddenly the
# order does matter.
#
# $Id: tkt2942.test,v 1.1.4.1 2009/05/18 16:14:26 drh Exp $
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl

ifcapable !subquery {
  finish_test

} {2,1,3,4}
do_test tkt2942.4 {
  execsql {
    SELECT group_concat(num) FROM (SELECT num FROM t1 ORDER BY rowid DESC);
  }
} {4,3,1,2}

do_test tkt2942-3841.1 {
  execsql {
    CREATE TABLE table2 (key TEXT, x TEXT);
    CREATE TABLE list (key TEXT, value TEXT);
  
    INSERT INTO table2 VALUES ("a", "alist");
    INSERT INTO table2 VALUES ("b", "blist");
    INSERT INTO list VALUES ("a", 1);
    INSERT INTO list VALUES ("a", 2);
    INSERT INTO list VALUES ("a", 3);
    INSERT INTO list VALUES ("b", 4);
    INSERT INTO list VALUES ("b", 5);
    INSERT INTO list VALUES ("b", 6);

    SELECT
      table2.x,
      (SELECT group_concat(list.value)
        FROM list
        WHERE list.key = table2.key)
    FROM table2;
  }
} {alist 1,2,3 blist 4,5,6}

finish_test