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SQLite training in Houston TX on 2019-11-05 (details)
Part of the 2019 Tcl Conference

Artifact 167eb4652eccbedb199b6f21850346c3f5d779fb:


# 2001 September 15
#
# 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 implements regression tests for SQLite library.
#
# The focus of this file is testing the ability of the database to
# uses its rollback journal to recover intact (no database corruption)
# from a power failure during the middle of a COMMIT.  The OS interface
# modules are overloaded using the modified I/O routines found in test6.c.  
# These routines allow us to simulate the kind of file damage that 
# occurs after a power failure.
#
# $Id: crash.test,v 1.23 2007/03/17 10:26:59 danielk1977 Exp $

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

ifcapable !crashtest {
  finish_test
  return
}

# set repeats 100
set repeats 10

# The following procedure computes a "signature" for table "abc".  If
# abc changes in any way, the signature should change.  
proc signature {} {
  return [db eval {SELECT count(*), md5sum(a), md5sum(b), md5sum(c) FROM abc}]
}
proc signature2 {} {
  return [db eval {SELECT count(*), md5sum(a), md5sum(b), md5sum(c) FROM abc2}]
}

#--------------------------------------------------------------------------
# Simple crash test:
#
# crash-1.1: Create a database with a table with two rows.
# crash-1.2: Run a 'DELETE FROM abc WHERE a = 1' that crashes during
#            the first journal-sync.
# crash-1.3: Ensure the database is in the same state as after crash-1.1.
# crash-1.4: Run a 'DELETE FROM abc WHERE a = 1' that crashes during
#            the first database-sync.
# crash-1.5: Ensure the database is in the same state as after crash-1.1.
# crash-1.6: Run a 'DELETE FROM abc WHERE a = 1' that crashes during
#            the second journal-sync.
# crash-1.7: Ensure the database is in the same state as after crash-1.1.
#
# Tests 1.8 through 1.11 test for crashes on the third journal sync and
# second database sync.  Neither of these is required in such a small test
# case, so these tests are just to verify that the test infrastructure
# operates as expected.
#
do_test crash-1.1 {
  execsql {
    CREATE TABLE abc(a, b, c);
    INSERT INTO abc VALUES(1, 2, 3);
    INSERT INTO abc VALUES(4, 5, 6);
  }
  set ::sig [signature]
  expr 0
} {0}
do_test crash-1.2 {
  crashsql -delay 1 -file test.db-journal {
    DELETE FROM abc WHERE a = 1;
  }
} {1 {child process exited abnormally}}
do_test crash-1.3 {
  signature
} $::sig
do_test crash-1.4 {
  crashsql -delay 1 -file test.db {
    DELETE FROM abc WHERE a = 1;
  }
} {1 {child process exited abnormally}}
do_test crash-1.5 {
  signature
} $::sig
do_test crash-1.6 {
  crashsql -delay 2 -file test.db-journal {
    DELETE FROM abc WHERE a = 1;
  }
} {1 {child process exited abnormally}}
do_test crash-1.7 {
  catchsql {
    SELECT * FROM abc;
  }
} {0 {1 2 3 4 5 6}}

do_test crash-1.8 {
  crashsql -delay 3 -file test.db-journal {
    DELETE FROM abc WHERE a = 1;
  }
} {0 {}}
do_test crash-1.9 {
  catchsql {
    SELECT * FROM abc;
  }
} {0 {4 5 6}}
do_test crash-1.10 {
  crashsql -delay 2 -file test.db {
    DELETE FROM abc WHERE a = 4;
  }
} {0 {}}
do_test crash-1.11 {
  catchsql {
    SELECT * FROM abc;
  }
} {0 {}}

#--------------------------------------------------------------------------
# The following tests test recovery when both the database file and the the
# journal file contain corrupt data. This can happen after pages are
# written to the database file before a transaction is committed due to
# cache-pressure.
#
# crash-2.1: Insert 18 pages of data into the database.
# crash-2.2: Check the database file size looks ok.
# crash-2.3: Delete 15 or so pages (with a 10 page page-cache), then crash.
# crash-2.4: Ensure the database is in the same state as after crash-2.1.
#
# Test cases crash-2.5 and crash-2.6 check that the database is OK if the 
# crash occurs during the main database file sync. But this isn't really
# different from the crash-1.* cases.
#
do_test crash-2.1 {
  execsql { BEGIN }
  for {set n 0} {$n < 1000} {incr n} {
    execsql "INSERT INTO abc VALUES($n, [expr 2*$n], [expr 3*$n])"
  }
  execsql { COMMIT }
  set ::sig [signature]
  execsql { SELECT sum(a), sum(b), sum(c) from abc }
} {499500 999000 1498500}
do_test crash-2.2 {
  expr ([file size test.db] / 1024)>16
} {1}
do_test crash-2.3 {
  crashsql -delay 2 -file test.db-journal {
    DELETE FROM abc WHERE a < 800;
  }
} {1 {child process exited abnormally}}
do_test crash-2.4 {
  signature
} $sig
do_test crash-2.5 {
  crashsql -delay 1 -file test.db {
    DELETE FROM abc WHERE a<800;
  }
} {1 {child process exited abnormally}}
do_test crash-2.6 {
  signature
} $sig

#--------------------------------------------------------------------------
# The crash-3.* test cases are essentially the same test as test case
# crash-2.*, but with a more complicated data set. 
#
# The test is repeated a few times with different seeds for the random
# number generator in the crashing executable. Because there is no way to
# seed the random number generator directly, some SQL is added to the test
# case to 'use up' a different quantity random numbers before the test SQL
# is executed.
#

# Make sure the file is much bigger than the pager-cache (10 pages). This
# ensures that cache-spills happen regularly.
do_test crash-3.0 {
  execsql {
    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;
  }
  expr ([file size test.db] / 1024) > 450
} {1}
for {set i 1} {$i < $repeats} {incr i} {
  set sig [signature]
  do_test crash-3.$i.1 {
     crashsql -delay [expr $i%5 + 1] -file test.db-journal "
       BEGIN;
       SELECT random() FROM abc LIMIT $i;
       INSERT INTO abc VALUES(randstr(10,10), 0, 0);
       DELETE FROM abc WHERE random()%10!=0;
       COMMIT;
     "
  } {1 {child process exited abnormally}}
  do_test crash-3.$i.2 {
    signature
  } $sig
} 

#--------------------------------------------------------------------------
# The following test cases - crash-4.* - test the correct recovery of the
# database when a crash occurs during a multi-file transaction.
#
# crash-4.1.*: Test recovery when crash occurs during sync() of the 
#              main database journal file.
# crash-4.2.*: Test recovery when crash occurs during sync() of an 
#              attached database journal file.
# crash-4.3.*: Test recovery when crash occurs during sync() of the master
#              journal file. 
#
do_test crash-4.0 {
  file delete -force test2.db
  file delete -force test2.db-journal
  execsql {
    ATTACH 'test2.db' AS aux;
    PRAGMA aux.default_cache_size = 10;
    CREATE TABLE aux.abc2 AS SELECT 2*a as a, 2*b as b, 2*c as c FROM abc;
  }
  expr ([file size test2.db] / 1024) > 450
} {1}

for {set i 1} {$i<$repeats} {incr i} {
  set sig [signature]
  set sig2 [signature2]
  do_test crash-4.1.$i.1 {
     set c [crashsql -delay $i -file test.db-journal "
       ATTACH 'test2.db' AS aux;
       BEGIN;
       SELECT random() FROM abc LIMIT $i;
       INSERT INTO abc VALUES(randstr(10,10), 0, 0);
       DELETE FROM abc WHERE random()%10!=0;
       INSERT INTO abc2 VALUES(randstr(10,10), 0, 0);
       DELETE FROM abc2 WHERE random()%10!=0;
       COMMIT;
     "]
     set c
  } {1 {child process exited abnormally}}
  do_test crash-4.1.$i.2 {
    signature
  } $sig
  do_test crash-4.1.$i.3 {
    signature2
  } $sig2
} 
set i 0
while {[incr i]} {
  set sig [signature]
  set sig2 [signature2]
  set ::fin 0
  do_test crash-4.2.$i.1 {
     set c [crashsql -delay $i -file test2.db-journal "
       ATTACH 'test2.db' AS aux;
       BEGIN;
       SELECT random() FROM abc LIMIT $i;
       INSERT INTO abc VALUES(randstr(10,10), 0, 0);
       DELETE FROM abc WHERE random()%10!=0;
       INSERT INTO abc2 VALUES(randstr(10,10), 0, 0);
       DELETE FROM abc2 WHERE random()%10!=0;
       COMMIT;
     "]
     if { $c == {0 {}} } {
       set ::fin 1
       set c {1 {child process exited abnormally}}
     }
     set c
  } {1 {child process exited abnormally}}
  if { $::fin } break
  do_test crash-4.2.$i.2 {
    signature
  } $sig
  do_test crash-4.2.$i.3 {
    signature2
  } $sig2
} 
for {set i 1} {$i < 5} {incr i} {
  set sig [signature]
  set sig2 [signature2]
  do_test crash-4.3.$i.1 {
     crashsql -delay 1 -file test.db-mj* "
       ATTACH 'test2.db' AS aux;
       BEGIN;
       SELECT random() FROM abc LIMIT $i;
       INSERT INTO abc VALUES(randstr(10,10), 0, 0);
       DELETE FROM abc WHERE random()%10!=0;
       INSERT INTO abc2 VALUES(randstr(10,10), 0, 0);
       DELETE FROM abc2 WHERE random()%10!=0;
       COMMIT;
     "
  } {1 {child process exited abnormally}}
  do_test crash-4.3.$i.2 {
    signature
  } $sig
  do_test crash-4.3.$i.3 {
    signature2
  } $sig2
}

#--------------------------------------------------------------------------
# The following test cases - crash-5.* - exposes a bug that existed in the
# sqlite3pager_movepage() API used by auto-vacuum databases.
# database when a crash occurs during a multi-file transaction. See comments
# in test crash-5.3 for details.
#
db close
file delete -force test.db
sqlite3 db test.db
do_test crash-5.1 {
  execsql {
    CREATE TABLE abc(a, b, c);                          -- Root page 3
    INSERT INTO abc VALUES(randstr(1500,1500), 0, 0);   -- Overflow page 4
    INSERT INTO abc SELECT * FROM abc;
    INSERT INTO abc SELECT * FROM abc;
    INSERT INTO abc SELECT * FROM abc;
  }
} {}
do_test crash-5.2 {
  expr [file size test.db] / 1024
} [expr [string match [execsql {pragma auto_vacuum}] 1] ? 11 : 10]
set sig [signature]
do_test crash-5.3 {
# The SQL below is used to expose a bug that existed in
# sqlite3pager_movepage() during development of the auto-vacuum feature. It
# functions as follows:
# 
# 1: Begin a transaction.
# 2: Put page 4 on the free-list (was the overflow page for the row deleted).
# 3: Write data to page 4 (it becomes the overflow page for the row inserted).
#    The old page 4 data has been written to the journal file, but the
#    journal file has not been sync()hronized.
# 4: Create a table, which calls sqlite3pager_movepage() to move page 4
#    to the end of the database (page 12) to make room for the new root-page.
# 5: Put pressure on the pager-cache. This results in page 4 being written
#    to the database file to make space in the cache to load a new page. The
#    bug was that page 4 was written to the database file before the journal
#    is sync()hronized.
# 6: Commit. A crash occurs during the sync of the journal file.
#
# End result: Before the bug was fixed, data has been written to page 4 of the
# database file and the journal file does not contain trustworthy rollback
# data for this page.
#
  crashsql -delay 1 -file test.db-journal {
    BEGIN;                                             -- 1
    DELETE FROM abc WHERE oid = 1;                     -- 2
    INSERT INTO abc VALUES(randstr(1500,1500), 0, 0);  -- 3
    CREATE TABLE abc2(a, b, c);                        -- 4
    SELECT * FROM abc;                                 -- 5
    COMMIT;                                            -- 6
  }
} {1 {child process exited abnormally}}
integrity_check crash-5.4
do_test crash-5.5 {
  signature
} $sig

#--------------------------------------------------------------------------
# The following test cases - crash-6.* - test that a DROP TABLE operation
# is correctly rolled back in the event of a crash while the database file
# is being written. This is mainly to test that all pages are written to the
# journal file before truncation in an auto-vacuum database.
#
do_test crash-6.1 {
  crashsql -delay 1 -file test.db {
    DROP TABLE abc;
  }
} {1 {child process exited abnormally}}
do_test crash-6.2 {
  signature
} $sig

#--------------------------------------------------------------------------
# These test cases test the case where the master journal file name is 
# corrupted slightly so that the corruption has to be detected by the
# checksum.
do_test crash-7.1 {
  crashsql -delay 1 -file test.db {
    ATTACH 'test2.db' AS aux;
    BEGIN;
    INSERT INTO abc VALUES(randstr(1500,1500), 0, 0);
    INSERT INTO abc2 VALUES(randstr(1500,1500), 0, 0);
    COMMIT;
  }

  # Change the checksum value for the master journal name.
  set f [open test.db-journal a]
  fconfigure $f -encoding binary
  seek $f [expr [file size test.db-journal] - 12]
  puts -nonewline $f "\00\00\00\00"
  close $f
} {}
do_test crash-7.2 {
  signature
} $sig

finish_test