# 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().

 #

 # Prior to version 3.6.2, calling sqlite3_release_memory() or exceeding

 # the configured soft heap limit could cause sqlite to upgrade database 

 # locks and flush dirty pages to the file system. As of 3.6.2, this is

 # no longer the case. In version 3.6.2, sqlite3_release_memory() only

 # reclaims clean pages. This test file has been updated accordingly.

 #

 # $Id: malloc5.test,v 1.20 2008/08/27 16:38:57 danielk1977 Exp $

 set testdir [file dirname $argv0]

 source $testdir/tester.tcl

 source $testdir/malloc_common.tcl

 db close

 # Only run these tests if memory debugging is turned on.

 #

 if {!$MEMDEBUG} {

    puts "Skipping malloc5 tests: not compiled with -DSQLITE_MEMDEBUG..."

    finish_test

    return

 }

 # Skip these tests if OMIT_MEMORY_MANAGEMENT was defined at compile time.

 ifcapable !memorymanage {

    finish_test

    return

 }

 sqlite3_soft_heap_limit 0

 sqlite3 db test.db

 do_test malloc5-1.1 {

   # Simplest possible test. Call sqlite3_release_memory when there is exactly

   # one unused page in a single pager cache. The page cannot be freed, as

   # it is dirty. So sqlite3_release_memory() returns 0.

   #

   execsql {

     PRAGMA auto_vacuum=OFF;

     BEGIN;

     CREATE TABLE abc(a, b, c);

   }

   sqlite3_release_memory

 } {0}

 do_test malloc5-1.2 {

   # Test that the transaction started in the above test is still active.

   # The lock on the database file should not have been upgraded (this was

   # not the case before version 3.6.2).

   #

   sqlite3 db2 test.db

   execsql { SELECT * FROM sqlite_master } db2

 } {}

 do_test malloc5-1.3 {

   # Call [sqlite3_release_memory] when there is exactly one unused page 

   # in the cache belonging to db2.

   #

   set ::pgalloc [sqlite3_release_memory]

   expr $::pgalloc > 0

 } {1}

 do_test malloc5-1.4 {

   # Commit the transaction and open a new one. Read 1 page into the cache.

   # Because the page is not dirty, it is eligible for collection even

   # before the transaction is concluded.

   #

   execsql {

     COMMIT;

     BEGIN;

     SELECT * FROM abc;

   }

   sqlite3_release_memory

 } $::pgalloc

 do_test malloc5-1.5 {

   # Conclude the transaction opened in the previous [do_test] block. This

   # causes another page (page 1) to become eligible for recycling.

   #

   execsql { COMMIT }

   sqlite3_release_memory

 } $::pgalloc

 do_test malloc5-1.6 {

   # Manipulate the cache so that it contains two unused pages. One requires 

   # a journal-sync to free, the other does not.

   db2 close

   execsql {

     BEGIN;

     SELECT * FROM abc;

     CREATE TABLE def(d, e, f);

   }

   sqlite3_release_memory 500

 } $::pgalloc

 do_test malloc5-1.7 {

   # Database should not be locked this time. 

   sqlite3 db2 test.db

   catchsql { SELECT * FROM abc } db2

 } {0 {}}

 do_test malloc5-1.8 {

   # Try to release another block of memory. This will fail as the only

   # pages currently in the cache are dirty (page 3) or pinned (page 1).

   db2 close

   sqlite3_release_memory 500

 } 0

 do_test malloc5-1.8 {

   # Database is still not locked.

   #

   sqlite3 db2 test.db

   catchsql { SELECT * FROM abc } db2

 } {0 {}}

 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).

   sqlite3_release_memory

   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

 puts "Highwater mark: [sqlite3_memory_highwater]"

 # 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]

 execsql {PRAGMA cache_size=2000}

 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;}

   sqlite3_release_memory

   sqlite3_memory_highwater 1

   execsql {SELECT * FROM abc}

   set nMaxBytes [sqlite3_memory_highwater 1]

   puts -nonewline " (Highwater mark: $nMaxBytes) "

   expr $nMaxBytes > 1000000

 } {1}

 do_test malloc5-4.2 {

   sqlite3_release_memory

   sqlite3_soft_heap_limit 100000

   sqlite3_memory_highwater 1

   execsql {SELECT * FROM abc}

   set nMaxBytes [sqlite3_memory_highwater 1]

   puts -nonewline " (Highwater mark: $nMaxBytes) "

   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 10000 [expr int(10000.0 * 4999.5)] [expr int(10000.0 * 4999.5)]]

 # Restore the soft heap limit.

 sqlite3_soft_heap_limit $::soft_limit

 # Test that there are no problems calling sqlite3_release_memory when

 # there are open in-memory databases.

 #

 # At one point these tests would cause a seg-fault.

 #

 do_test malloc5-5.1 {

   db close

   sqlite3 db :memory:

   execsql {

     BEGIN;

     CREATE TABLE abc(a, b, c);

     INSERT INTO abc VALUES('abcdefghi', 1234567890, NULL);

     INSERT INTO abc SELECT * FROM abc;

     INSERT INTO abc SELECT * FROM abc;

     INSERT INTO abc SELECT * FROM abc;

     INSERT INTO abc SELECT * FROM abc;

     INSERT INTO abc SELECT * FROM abc;

     INSERT INTO abc SELECT * FROM abc;

     INSERT INTO abc SELECT * FROM abc;

   }

   sqlite3_release_memory

 } 0

 do_test malloc5-5.2 {

   sqlite3_soft_heap_limit 5000

   execsql {

     COMMIT;

     PRAGMA temp_store = memory;

     SELECT * FROM abc ORDER BY a;

   }

   expr 1

 } {1}

 sqlite3_soft_heap_limit $::soft_limit

 #-------------------------------------------------------------------------

 # The following test cases (malloc5-6.*) test the new global LRU list

 # used to determine the pages to recycle when sqlite3_release_memory is

 # called and there is more than one pager open.

 #

 proc nPage {db} {

   set bt [btree_from_db $db]

   array set stats [btree_pager_stats $bt]

   set stats(page)

 }

 db close

 file delete -force test.db test.db-journal test2.db test2.db-journal

 # This block of test-cases (malloc5-6.1.*) prepares two database files

 # for the subsequent tests.

 do_test malloc5-6.1.1 {

   sqlite3 db test.db

   execsql {

     PRAGMA page_size=1024;

     PRAGMA default_cache_size=10;

   }

   execsql {

     PRAGMA temp_store = memory;

     BEGIN;

     CREATE TABLE abc(a PRIMARY KEY, b, c);

     INSERT INTO abc VALUES(randstr(50,50), randstr(75,75), randstr(100,100));

     INSERT INTO abc 

         SELECT randstr(50,50), randstr(75,75), randstr(100,100) FROM abc;

     INSERT INTO abc 

         SELECT randstr(50,50), randstr(75,75), randstr(100,100) FROM abc;

     INSERT INTO abc 

         SELECT randstr(50,50), randstr(75,75), randstr(100,100) FROM abc;

     INSERT INTO abc 

         SELECT randstr(50,50), randstr(75,75), randstr(100,100) FROM abc;

     INSERT INTO abc 

         SELECT randstr(50,50), randstr(75,75), randstr(100,100) FROM abc;

     INSERT INTO abc 

         SELECT randstr(50,50), randstr(75,75), randstr(100,100) FROM abc;

     COMMIT;

   } 

   copy_file test.db test2.db

   sqlite3 db2 test2.db

   list \

     [expr ([file size test.db]/1024)>20] [expr ([file size test2.db]/1024)>20]

 } {1 1}

 do_test malloc5-6.1.2 {

   list [execsql {PRAGMA cache_size}] [execsql {PRAGMA cache_size} db2]

 } {10 10}

 do_test malloc5-6.2.1 {

 breakpoint

   execsql {SELECT * FROM abc} db2

   execsql {SELECT * FROM abc} db

   expr [nPage db] + [nPage db2]

 } {20}

 do_test malloc5-6.2.2 {

   # If we now try to reclaim some memory, it should come from the db2 cache.

   sqlite3_release_memory 3000

   expr [nPage db] + [nPage db2]

 } {17}

 do_test malloc5-6.2.3 {

   # Access the db2 cache again, so that all the db2 pages have been used

   # more recently than all the db pages. Then try to reclaim 3000 bytes.

   # This time, 3 pages should be pulled from the db cache.

   execsql { SELECT * FROM abc } db2

   sqlite3_release_memory 3000

   expr [nPage db] + [nPage db2]

 } {17}

 do_test malloc5-6.3.1 {

   # Now open a transaction and update 2 pages in the db2 cache. Then

   # do a SELECT on the db cache so that all the db pages are more recently

   # used than the db2 pages. When we try to free memory, SQLite should

   # free the non-dirty db2 pages, then the db pages, then finally use

   # sync() to free up the dirty db2 pages. The only page that cannot be

   # freed is page1 of db2. Because there is an open transaction, the

   # btree layer holds a reference to page 1 in the db2 cache.

   execsql {

     BEGIN;

     UPDATE abc SET c = randstr(100,100) 

     WHERE rowid = 1 OR rowid = (SELECT max(rowid) FROM abc);

   } db2

   execsql { SELECT * FROM abc } db

   expr [nPage db] + [nPage db2]

 } {20}

 do_test malloc5-6.3.2 {

   # Try to release 7700 bytes. This should release all the 

   # non-dirty pages held by db2.

   sqlite3_release_memory [expr 7*1100]

   list [nPage db] [nPage db2]

 } {10 3}

 do_test malloc5-6.3.3 {

   # Try to release another 1000 bytes. This should come fromt the db

   # cache, since all three pages held by db2 are either in-use or diry.

   sqlite3_release_memory 1000

   list [nPage db] [nPage db2]

 } {9 3}

 do_test malloc5-6.3.4 {

   # Now release 9900 more (about 9 pages worth). This should expunge

   # the rest of the db cache. But the db2 cache remains intact, because

   # SQLite tries to avoid calling sync().

   sqlite3_release_memory 9900

   list [nPage db] [nPage db2]

 } {0 3}

 do_test malloc5-6.3.5 {

   # But if we are really insistent, SQLite will consent to call sync()

   # if there is no other option. UPDATE: As of 3.6.2, SQLite will not

   # call sync() in this scenario. So no further memory can be reclaimed.

   sqlite3_release_memory 1000

   list [nPage db] [nPage db2]

 } {0 3}

 do_test malloc5-6.3.6 {

   # The referenced page (page 1 of the db2 cache) will not be freed no

   # matter how much memory we ask for:

   sqlite3_release_memory 31459

   list [nPage db] [nPage db2]

 } {0 3}

 db2 close

 sqlite3_soft_heap_limit $::soft_limit

 finish_test

 catch {db close}