test/malloc5.test

# 2005 November 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.
#
#***********************************************************************
#
# This file contains test cases focused on the two memory-management APIs, 
# sqlite3_soft_heap_limit() and sqlite3_release_memory().
#
# $Id: malloc5.test,v 1.4 2006/01/05 15:50:07 drh Exp $

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

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

# Only run these tests if memory debugging is turned on.
if {[info command sqlite_malloc_stat]==""} {
   puts "Skipping malloc tests: not compiled with -DSQLITE_MEMDEBUG..."
   finish_test
   return
}

do_test malloc5-1.1 {
  # Simplest possible test. Call sqlite3_release_memory when there is exactly
  # one unused page in a single pager cache. This test case set's the 
  # value of the ::pgalloc variable, which is used in subsequent tests.
  #
  # Note: Even though executing this statement on an empty database 
  # modifies 2 pages (the root of sqlite_master and the new root page), 
  # the sqlite_master root (page 1) is never freed because the btree layer
  # retains a reference to it for the entire transaction. 
  execsql {
    BEGIN;
    CREATE TABLE abc(a, b, c);
  }
  set ::pgalloc [sqlite3_release_memory]
  expr $::pgalloc > 0
} {1}
do_test malloc5-1.2 {
  # Test that the transaction started in the above test is still active.
  # Because the page freed had been written to, freeing it required a
  # journal sync and exclusive lock on the database file. Test the file
  # appears to be locked.
  sqlite3 db2 test.db
  catchsql {
    SELECT * FROM abc;
  } db2
} {1 {database is locked}}
do_test malloc5-1.3 {
  # Again call [sqlite3_release_memory] when there is exactly one unused page 
  # in the cache. The same amount of memory is required, but no journal-sync
  # or exclusive lock should be established.
  execsql {
    COMMIT;
    BEGIN;
    SELECT * FROM abc;
  }
  sqlite3_release_memory
} $::pgalloc
do_test malloc5-1.4 {
  # Database should not be locked this time.
  catchsql {
    SELECT * FROM abc;
  } db2
} {0 {}}
do_test malloc5-1.5 {
  # Manipulate the cache so that it contains two unused pages. One requires 
  # a journal-sync to free, the other does not.
  execsql {
    SELECT * FROM abc;
    CREATE TABLE def(d, e, f);
  }
  sqlite3_release_memory 500
} $::pgalloc
do_test malloc5-1.6 {
  # Database should not be locked this time. The above test case only
  # requested 500 bytes of memory, which can be obtained by freeing the page
  # that does not require an fsync().
  catchsql {
    SELECT * FROM abc;
  } db2
} {0 {}}
do_test malloc5-1.7 {
  # Release another 500 bytes of memory. This time we require a sync(), 
  # so the database file will be locked afterwards.
  sqlite3_release_memory 500
} $::pgalloc
do_test malloc5-1.8 {
  catchsql {
    SELECT * FROM abc;
  } db2
} {1 {database is locked}}
do_test malloc5-1.9 {
  execsql {
    COMMIT;
  }
} {}

do_test malloc5-2.1 {
  # Put some data in tables abc and def. Both tables are still wholly 
  # contained within their root pages.
  execsql {
    INSERT INTO abc VALUES(1, 2, 3);
    INSERT INTO abc VALUES(4, 5, 6);
    INSERT INTO def VALUES(7, 8, 9);
    INSERT INTO def VALUES(10,11,12);
  }
} {}
do_test malloc5-2.2 {
  # Load the root-page for table def into the cache. Then query table abc. 
  # Halfway through the query call sqlite3_release_memory(). The goal of this
  # test is to make sure we don't free pages that are in use (specifically, 
  # the root of table abc).
  set nRelease 0
  execsql { 
    BEGIN;
    SELECT * FROM def;
  }
  set data [list]
  db eval {SELECT * FROM abc} {
    incr nRelease [sqlite3_release_memory]
    lappend data $a $b $c
  }
  execsql {
    COMMIT;
  }
  list $nRelease $data
} [list $pgalloc [list 1 2 3 4 5 6]]

do_test malloc5-3.1 {
  # Simple test to show that if two pagers are opened from within this
  # thread, memory is freed from both when sqlite3_release_memory() is
  # called.
  execsql {
    BEGIN;
    SELECT * FROM abc;
  }
  execsql {
    SELECT * FROM sqlite_master;
    BEGIN;
    SELECT * FROM def;
  } db2
  sqlite3_release_memory
} [expr $::pgalloc * 2]
do_test malloc5-3.2 {
  concat \
    [execsql {SELECT * FROM abc; COMMIT}] \
    [execsql {SELECT * FROM def; COMMIT} db2]
} {1 2 3 4 5 6 7 8 9 10 11 12}

db2 close
sqlite_malloc_outstanding -clearmaxbytes

# The following two test cases each execute a transaction in which 
# 10000 rows are inserted into table abc. The first test case is used
# to ensure that more than 1MB of dynamic memory is used to perform
# the transaction. 
#
# The second test case sets the "soft-heap-limit" to 100,000 bytes (0.1 MB)
# and tests to see that this limit is not exceeded at any point during 
# transaction execution.
#
# Before executing malloc5-4.* we save the value of the current soft heap 
# limit in variable ::soft_limit. The original value is restored after 
# running the tests.
#
set ::soft_limit [sqlite3_soft_heap_limit -1]
do_test malloc5-4.1 {
  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]
  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]
  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;
  }
} [list 20000 [expr int(20000.0 * 4999.5)] [expr int(20000.0 * 4999.5)]]

# Restore the soft heap limit.
sqlite3_soft_heap_limit $::soft_limit

finish_test