[sqlite] Remove obsolete reference version 3.8.7.4.

third_party/sqlite/sqlite-src-3080704/test/thread005.test

-# 2009 March 11
-#
-# 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.
-#
-#***********************************************************************
-#
-# Test a race-condition that shows up in shared-cache mode.
-#
-# $Id: thread005.test,v 1.5 2009/03/26 14:48:07 danielk1977 Exp $
-
-set testdir [file dirname $argv0]
-
-source $testdir/tester.tcl
-if {[run_thread_tests]==0} { finish_test ; return }
-ifcapable !shared_cache {
-  finish_test
-  return
-}
-
-db close
-
-# Use shared-cache mode for these tests.
-# 
-set ::enable_shared_cache [sqlite3_enable_shared_cache]
-sqlite3_enable_shared_cache 1
-
-#-------------------------------------------------------------------------
-# This test attempts to hit the race condition fixed by commit [6363].
-#
-proc runsql {zSql {db {}}} {
-  set rc SQLITE_OK
-  while {$rc=="SQLITE_OK" && $zSql ne ""} {
-    set STMT [sqlite3_prepare_v2 $db $zSql -1 zSql]
-    while {[set rc [sqlite3_step $STMT]] eq "SQLITE_ROW"} { }
-    set rc [sqlite3_finalize $STMT]
-  }
-  return $rc
-}
-do_test thread005-1.1 {
-  sqlite3 db test.db
-  db eval { CREATE TABLE t1(a, b) }
-  db close
-} {}
-for {set ii 2} {$ii < 500} {incr ii} {
-  unset -nocomplain finished
-  thread_spawn finished(0) {sqlite3_open test.db}
-  thread_spawn finished(1) {sqlite3_open test.db}
-  if {![info exists finished(0)]} { vwait finished(0) }
-  if {![info exists finished(1)]} { vwait finished(1) }
-
-  do_test thread005-1.$ii {
-    runsql { BEGIN }                       $finished(0)
-    runsql { INSERT INTO t1 VALUES(1, 2) } $finished(0)
-
-    # If the race-condition was hit, then $finished(0 and $finished(1)
-    # will not use the same pager cache. In this case the next statement
-    # can be executed succesfully. However, if the race-condition is not
-    # hit, then $finished(1) will be blocked by the write-lock held by 
-    # $finished(0) on the shared-cache table t1 and the statement will
-    # return SQLITE_LOCKED.
-    #
-    runsql { SELECT * FROM t1 }            $finished(1)
-  } {SQLITE_LOCKED}
-
-  sqlite3_close $finished(0)
-  sqlite3_close $finished(1)
-}
-
-
-#-------------------------------------------------------------------------
-# This test tries to exercise a race-condition that existed in shared-cache
-# mode at one point. The test uses two threads; each has a database connection
-# open on the same shared cache. The schema of the database is:
-#
-#    CREATE TABLE t1(a INTEGER PRIMARY KEY, b UNIQUE);
-#
-# One thread is a reader and the other thread a reader and a writer. The 
-# writer thread repeats the following transaction as fast as possible:
-# 
-#      BEGIN;
-#        DELETE FROM t1 WHERE a = (SELECT max(a) FROM t1);
-#        INSERT INTO t1 VALUES(NULL, NULL);
-#        UPDATE t1 SET b = a WHERE a = (SELECT max(a) FROM t1);
-#        SELECT count(*) FROM t1 WHERE b IS NULL;
-#      COMMIT;
-#
-# The reader thread does the following over and over as fast as possible:
-#
-#      BEGIN;
-#        SELECT count(*) FROM t1 WHERE b IS NULL;
-#      COMMIT;
-#
-# The test runs for 20 seconds or until one of the "SELECT count(*)" 
-# statements returns a non-zero value. If an SQLITE_LOCKED error occurs,
-# the connection issues a ROLLBACK immediately to abandon the current
-# transaction.
-#
-# If everything is working correctly, the "SELECT count(*)" statements 
-# should never return a value other than 0. The "INSERT" statement 
-# executed by the writer adds a row with "b IS NULL" to the table, but
-# the subsequent UPDATE statement sets its "b" value to an integer
-# immediately afterwards.
-#
-# However, before the race-condition was fixed, if the reader's SELECT
-# statement hit an error (say an SQLITE_LOCKED) at the same time as the
-# writer was executing the UPDATE statement, then it could incorrectly
-# rollback the statement-transaction belonging to the UPDATE statement.
-# The UPDATE statement would still be reported as successful to the user,
-# but it would have no effect on the database contents.
-# 
-# Note that it has so far only proved possible to hit this race-condition
-# when using an ATTACHed database. There doesn't seem to be any reason
-# for this, other than that operating on an ATTACHed database means there
-# are a few more mutex grabs and releases during the window of time open
-# for the race-condition. Maybe this encourages the scheduler to context
-# switch or something...
-#
-
-forcedelete test.db test2.db
-unset -nocomplain finished
-
-do_test thread005-2.1 {
-  sqlite3 db test.db
-  execsql { ATTACH 'test2.db' AS aux }
-  execsql {
-    CREATE TABLE aux.t1(a INTEGER PRIMARY KEY, b UNIQUE);
-    INSERT INTO t1 VALUES(1, 1);
-    INSERT INTO t1 VALUES(2, 2);
-  }
-  db close
-} {}
-
-
-set ThreadProgram {
-  proc execsql {zSql {db {}}} {
-    if {$db eq ""} {set db $::DB}
-
-    set lRes [list]
-    set rc SQLITE_OK
-
-    while {$rc=="SQLITE_OK" && $zSql ne ""} {
-      set STMT [sqlite3_prepare_v2 $db $zSql -1 zSql]
-      while {[set rc [sqlite3_step $STMT]] eq "SQLITE_ROW"} {
-        for {set i 0} {$i < [sqlite3_column_count $STMT]} {incr i} {
-          lappend lRes [sqlite3_column_text $STMT 0]
-        }
-      }
-      set rc [sqlite3_finalize $STMT]
-    }
-
-    if {$rc != "SQLITE_OK"} { error "$rc [sqlite3_errmsg $db]" }
-    return $lRes
-  }
-
-  if {$isWriter} {
-    set Sql {
-      BEGIN;
-        DELETE FROM t1 WHERE a = (SELECT max(a) FROM t1);
-        INSERT INTO t1 VALUES(NULL, NULL);
-        UPDATE t1 SET b = a WHERE a = (SELECT max(a) FROM t1);
-        SELECT count(*) FROM t1 WHERE b IS NULL;
-      COMMIT;
-    }
-  } else {
-    set Sql {
-      BEGIN;
-      SELECT count(*) FROM t1 WHERE b IS NULL;
-      COMMIT;
-    }
-  }
-
-  set ::DB [sqlite3_open test.db]
-
-  execsql { ATTACH 'test2.db' AS aux }
-
-  set result "ok"
-  set finish [expr [clock_seconds]+5]
-  while {$result eq "ok" && [clock_seconds] < $finish} {
-    set rc [catch {execsql $Sql} msg]
-    if {$rc} {
-      if {[string match "SQLITE_LOCKED*" $msg]} {
-        catch { execsql ROLLBACK }
-      } else {
-        sqlite3_close $::DB
-        error $msg
-      }
-    } elseif {$msg ne "0"} {
-      set result "failed"
-    }
-  }
-
-  sqlite3_close $::DB
-  set result
-}
-
-# There is a race-condition in btree.c that means that if two threads
-# attempt to open the same database at roughly the same time, and there
-# does not already exist a shared-cache corresponding to that database,
-# then two shared-caches can be created instead of one. Things still more
-# or less work, but the two database connections do not use the same
-# shared-cache.
-#
-# If the threads run by this test hit this race-condition, the tests
-# fail (because SQLITE_BUSY may be unexpectedly returned instead of
-# SQLITE_LOCKED). To prevent this from happening, open a couple of
-# connections to test.db and test2.db now to make sure that there are
-# already shared-caches in memory for all databases opened by the
-# test threads.
-#
-sqlite3 db test.db
-sqlite3 db test2.db
-
-puts "Running thread-tests for ~20 seconds"
-thread_spawn finished(0) {set isWriter 0} $ThreadProgram
-thread_spawn finished(1) {set isWriter 1} $ThreadProgram
-if {![info exists finished(0)]} { vwait finished(0) }
-if {![info exists finished(1)]} { vwait finished(1) }
-
-catch { db close }
-catch { db2 close }
-
-do_test thread005-2.2 {
-  list $finished(0) $finished(1)
-} {ok ok}
-
-do_test thread005-2.3 {
-  sqlite3 db test.db
-  execsql { ATTACH 'test2.db' AS aux }
-  execsql { SELECT count(*) FROM t1 WHERE b IS NULL }
-} {0}
-
-sqlite3_enable_shared_cache $::enable_shared_cache
-finish_test