test/cache.test

# 2007 March 24
#
# 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: cache.test,v 1.2 2007/04/06 21:42:22 drh Exp $

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

ifcapable {!pager_pragmas} {
  finish_test
  return
}

proc pager_cache_size {db} {
  set bt [btree_from_db $db]
  array set stats [btree_pager_stats $bt]
  return $stats(page)
}

do_test cache-1.1 {
  pager_cache_size db
} {0}

do_test cache-1.2 {
  execsql {
    PRAGMA auto_vacuum=OFF;
    CREATE TABLE abc(a, b, c);
    INSERT INTO abc VALUES(1, 2, 3);
  }
  pager_cache_size db
} {2}

# At one point, repeatedly locking and unlocking the cache was causing
# a resource leak of one page per repetition. The page wasn't actually
# leaked, but would not be reused until the pager-cache was full (i.e. 
# 2000 pages by default).
#
# This tests that once the pager-cache is initialised, it can be locked
# and unlocked repeatedly without internally allocating any new pages.
#
set cache_size [pager_cache_size db]
for {set ii 0} {$ii < 10} {incr ii} {

  do_test cache-1.3.$ii {
    execsql {SELECT * FROM abc}
    pager_cache_size db
  } $::cache_size

}

finish_test