SQLite

/*
** 2004 April 6
**
** 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.
**
*************************************************************************
** $Id: btree.c,v 1.302 2006/01/19 08:43:31 danielk1977 Exp $
**
** This file implements a external (disk-based) database using BTrees.
** For a detailed discussion of BTrees, refer to
**
**     Donald E. Knuth, THE ART OF COMPUTER PROGRAMMING, Volume 3:
**     "Sorting And Searching", pages 473-480. Addison-Wesley
**     Publishing Company, Reading, Massachusetts.

** read cursors on the table.  Open write cursors are moved to the
** root of the table.
*/
int sqlite3BtreeClearTable(Btree *p, int iTable){
  int rc;
  BtCursor *pCur;
  BtShared *pBt = p->pBt;
  sqlite3 *db = p->pSqlite;
  if( p->inTrans!=TRANS_WRITE ){
    return pBt->readOnly ? SQLITE_READONLY : SQLITE_ERROR;
  }

  /* If this connection is not in read-uncommitted mode and currently has
  ** a read-cursor open on the table being cleared, return SQLITE_LOCKED.
  */
  if( 0==db || 0==(db->flags&SQLITE_ReadUncommitted) ){
    for(pCur=pBt->pCursor; pCur; pCur=pCur->pNext){
      if( pCur->pBtree==p && pCur->pgnoRoot==(Pgno)iTable ){
        if( 0==pCur->wrFlag ){
          return SQLITE_LOCKED;
        }
        moveToRoot(pCur);
      }
    }




  }

  /* Save the position of all cursors open on this table */
  if( SQLITE_OK!=(rc = saveAllCursors(pBt, iTable, 0)) ){
    return rc;
  }

  return clearDatabasePage(pBt, (Pgno)iTable, 0, 0);
}

/*
** Erase all information in a table and add the root of the table to
** the freelist.  Except, the root of the principle table (the one on
** page 1) is never added to the freelist.
**

#    May you share freely, never taking more than you give.
#
#***********************************************************************
#
# This file contains test cases focused on the two memory-management APIs, 
# sqlite3_soft_heap_limit() and sqlite3_release_memory().
#
# $Id: malloc5.test,v 1.7 2006/01/19 08:43:32 danielk1977 Exp $

#---------------------------------------------------------------------------
# NOTES ON EXPECTED BEHAVIOUR
#
#---------------------------------------------------------------------------

  execsql {BEGIN;}
  execsql {DELETE FROM abc;}
  for {set i 0} {$i < 10000} {incr i} {
    execsql "INSERT INTO abc VALUES($i, $i, '[string repeat X 100]');"
  }
  execsql {COMMIT;}
  set ::nMaxBytes [sqlite_malloc_outstanding -maxbytes]
  if {$::nMaxBytes==""} {set ::nMaxBytes 1000001}
  expr $::nMaxBytes > 1000000
} {1}
do_test malloc5-4.2 {
  sqlite3_release_memory
  sqlite_malloc_outstanding -clearmaxbytes
  sqlite3_soft_heap_limit 100000
  execsql {BEGIN;}
  for {set i 0} {$i < 10000} {incr i} {
    execsql "INSERT INTO abc VALUES($i, $i, '[string repeat X 100]');"
  }
  execsql {COMMIT;}
  set ::nMaxBytes [sqlite_malloc_outstanding -maxbytes]
  if {$::nMaxBytes==""} {set ::nMaxBytes 0}
  expr $::nMaxBytes <= 100000
} {1}
do_test malloc5-4.3 {
  # Check that the content of table abc is at least roughly as expected.
  execsql {
    SELECT count(*), sum(a), sum(b) FROM abc;
  }

# 2005 December 30
#
# 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.
#
#***********************************************************************
#
# $Id: shared.test,v 1.19 2006/01/19 08:43:32 danielk1977 Exp $

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

ifcapable !shared_cache {
  finish_test

#             external locking protocol is still working.
# shared-3.*: Simple test of read-uncommitted mode.
# shared-4.*: Check that the schema is locked and unlocked correctly.
# shared-5.*: Test that creating/dropping schema items works when databases
#             are attached in different orders to different handles.
# shared-6.*: Locking, UNION ALL queries and sub-queries.
# shared-7.*: Autovacuum and shared-cache.
# shared-8.*: Tests related to the text encoding of shared-cache databases.
# shared-9.*: TEMP triggers and shared-cache databases.
# shared-10.*: Tests of sqlite3_close().
#

do_test shared-$av.1.1 {
  # Open a second database on the file test.db. It should use the same pager
  # cache and schema as the original connection. Verify that only 1 file is 
  # opened.
  sqlite3 db2 test.db

# 2005 January 19
#
# 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.
#
#***********************************************************************
#
# $Id: shared2.test,v 1.1 2006/01/19 08:43:32 danielk1977 Exp $

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

ifcapable !shared_cache {
  finish_test
  return
}
set ::enable_shared_cache [sqlite3_enable_shared_cache 1]


# Test that if we delete all rows from a table any read-uncommitted 
# cursors are correctly invalidated. Test on both table and index btrees.
do_test shared2-1.1 {
  sqlite3 db1 test.db
  sqlite3 db2 test.db

  # Set up some data. Table "numbers" has 64 rows after this block 
  # is executed.
  execsql {
    BEGIN;
    CREATE TABLE numbers(a PRIMARY KEY, b);
    INSERT INTO numbers(oid) VALUES(NULL);
    INSERT INTO numbers(oid) SELECT NULL FROM numbers;
    INSERT INTO numbers(oid) SELECT NULL FROM numbers;
    INSERT INTO numbers(oid) SELECT NULL FROM numbers;
    INSERT INTO numbers(oid) SELECT NULL FROM numbers;
    INSERT INTO numbers(oid) SELECT NULL FROM numbers;
    INSERT INTO numbers(oid) SELECT NULL FROM numbers;
    UPDATE numbers set a = oid, b = 'abcdefghijklmnopqrstuvwxyz0123456789';
    COMMIT;
  } db1
} {}
do_test shared2-1.2 {
  # Put connection 2 in read-uncommitted mode and start a SELECT on table 
  # 'numbers'. Half way through the SELECT, use connection 1 to delete the
  # contents of this table.
  execsql {
    pragma read_uncommitted = 1;
  } db2
  set count [execsql {SELECT count(*) FROM numbers} db2]
  db2 eval {SELECT a FROM numbers ORDER BY oid} {
    if {$a==32} {
      execsql {
        BEGIN;
        DELETE FROM numbers;
      } db1
    }
  }
  list $a $count
} {32 64}
do_test shared2-1.3 {
  # Same test as 1.2, except scan using the index this time.
  execsql {
    ROLLBACK;
  } db1
  set count [execsql {SELECT count(*) FROM numbers} db2]
  db2 eval {SELECT a, b FROM numbers ORDER BY a} {
    if {$a==32} {
      execsql {
        DELETE FROM numbers;
      } db1
    }
  }
  list $a $count
} {32 64}

db1 close
db2 close

sqlite3_enable_shared_cache $::enable_shared_cache
finish_test