sqlite/test/mmapleak.test

# 2026 October 13
#
# 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 tests that growing an mmap() mapping of a database file
# whose page-size is not a multiple of the OS page size does not leak
# mappings in HAVE_MREMAP=0 builds.
#

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

ifcapable !mmap {
  finish_test
  return
}
if {![file readable /proc/self/maps]} {
  finish_test
  return
}

# Return the number of entries in /proc/self/maps for test.db
#
proc n_db_mappings {} {
  set path [file normalize test.db]
  set fd [open /proc/self/maps]
  set n 0
  foreach line [split [read $fd] "\n"] {
    if {[string match "*$path*" $line]} { incr n }
  }
  close $fd
  return $n
}

do_execsql_test 1.0 {
  PRAGMA page_size = 512;
  PRAGMA mmap_size = 10000000;
  CREATE TABLE t1(x);
} {10000000}

for {set ii 0} {$ii < 100} {incr ii} {
  do_execsql_test 1.$ii.1 {
    INSERT INTO t1 VALUES(randomblob(700));
    SELECT count(*) FROM t1;
  } [expr $ii+1]

  do_test 1.$ii.2 { n_db_mappings } 1
}

reset_db
do_execsql_test 2.0 {
  PRAGMA page_size = 512;
  PRAGMA auto_vacuum = full;
  PRAGMA mmap_size = 10000000;
  CREATE TABLE t1(x);
} {10000000}

for {set ii 0} {$ii < 10} {incr ii} {
  do_execsql_test 2.$ii.1 {
    WITH s(i) AS (SELECT 1 UNION ALL SELECT i+1 FROM s WHERE i<20)
    INSERT INTO t1 SELECT randomblob(700) FROM s;
    SELECT count(*) FROM t1;
  } 20

  do_execsql_test 2.$ii.2 {
    DELETE FROM t1;
    SELECT count(*) FROM t1;
  } 0

  do_test 2.$ii.3 { n_db_mappings } 1
}

finish_test