# 2013 March 20
#
# 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.
#
#***********************************************************************
#

set testdir [file dirname $argv0]
source $testdir/tester.tcl
source $testdir/lock_common.tcl
set testprefix mmap1

proc nRead {db} {
  set bt [btree_from_db $db]
  db_enter $db
  array set stats [btree_pager_stats $bt]
  db_leave $db
  return $stats(read)
}

foreach {t mmap_size nRead} {
  1 { PRAGMA mmap_size = -65536 }   4
  2 { PRAGMA mmap_size = -50    } 156
  3 { PRAGMA mmap_size = 0      } 344
} {
  do_multiclient_test tn {
    sql1 $mmap_size

    code2 {
      set ::rcnt 0
      proc rblob {n} {
        set ::rcnt [expr (($::rcnt << 3) + $::rcnt + 456) & 0xFFFFFFFF]
        set str [format %.8x [expr $::rcnt ^ 0xbdf20da3]] 
        string range [string repeat $str [expr $n/4]] 1 $n
      }
      db2 func rblob rblob
    }

    sql2 { 
      PRAGMA auto_vacuum = 1;
      CREATE TABLE t1(a, b, UNIQUE(a, b));
      INSERT INTO t1 VALUES(rblob(500), rblob(500));
      INSERT INTO t1 SELECT rblob(500), rblob(500) FROM t1; --    2
      INSERT INTO t1 SELECT rblob(500), rblob(500) FROM t1; --    4
      INSERT INTO t1 SELECT rblob(500), rblob(500) FROM t1; --    8
      INSERT INTO t1 SELECT rblob(500), rblob(500) FROM t1; --   16
      INSERT INTO t1 SELECT rblob(500), rblob(500) FROM t1; --   32
    }
    do_test $t.$tn.1 {
      sql1 "SELECT count(*) FROM t1; PRAGMA integrity_check ; PRAGMA page_count"
    } {32 ok 77}

    # Have connection 2 shrink the file. Check connection 1 can still read it.
    sql2 { DELETE FROM t1 WHERE rowid%2; }
    do_test $t.$tn.2 {
      sql1 "SELECT count(*) FROM t1; PRAGMA integrity_check ; PRAGMA page_count"
    } {16 ok 42}

    # Have connection 2 grow the file. Check connection 1 can still read it.
    sql2 { INSERT INTO t1 SELECT rblob(500), rblob(500) FROM t1 }
    do_test $t.$tn.3 {
      sql1 "SELECT count(*) FROM t1; PRAGMA integrity_check ; PRAGMA page_count"
    } {32 ok 79}

    # Have connection 2 grow the file again. Check connection 1 is still ok.
    sql2 { INSERT INTO t1 SELECT rblob(500), rblob(500) FROM t1 }
    do_test $t.$tn.4 {
      sql1 "SELECT count(*) FROM t1; PRAGMA integrity_check ; PRAGMA page_count"
    } {64 ok 149}

    # Check that the number of pages read by connection 1 indicates that the
    # "PRAGMA mmap_size" command worked.
    do_test $t.$tn.5 { nRead db } $nRead
  }
}


finish_test