📄 lock_test.pl
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#!/usr/bin/perl# This is a test with uses two processes to a database.# The other inserts records in two tables, the other does a lot of joins# on these.# Every time the read thread outputs info, it does a ALTER TABLE command# which should stop the insert thread until the ALTER TABLE command is ready.## Warning, the output from this test will differ in 'found' from time to time,# but there should never be any errors#$host = shift || "";$test_db="test";$test_count=10000;srand 0; # Repeatable testuse Mysql;$|= 1; # Autoflush$dbh = Mysql->Connect($host) || die "Can't connect: $Mysql::db_errstr\n";$dbh->SelectDB($test_db) || die "Can't use database $test_db: $Mysql::db_errstr\n";$firsttable = "test_lock_1";$secondtable = "test_lock_2";$dbh->Query("drop table $firsttable");$dbh->Query("drop table $secondtable");print "Creating tables $firsttable and $secondtable in database $test_db\n";$dbh->Query("create table $firsttable (id int(6) not null, info char(32), auto int(11) not null auto_increment, primary key(id),key(auto))") or die $Mysql::db_errstr;$dbh->Query("create table $secondtable (id int(6) not null, info varchar(32), key(id))") or die $Mysql::db_errstr;$dbh=0; # Close handlerif (fork() == 0){ # Insert process $dbh = Mysql->Connect($host) || die "Can't connect: $Mysql::db_errstr\n"; $dbh->SelectDB($test_db) || die "Can't use database $test_db: $Mysql::db_errstr\n"; $first_id=1; $second_id=1; $first_count=$second_count=0; print "Writing started\n"; for ($i=1 ; $i <= $test_count ; $i++) { if (rand(3) <= 1) { $sth=$dbh->Query("insert into $firsttable values ($first_id,'This is entry $i',NULL)") || die "Got error on insert: $Mysql::db_errstr\n"; die "Row not inserted, aborting\n" if ($sth->affected_rows != 1); $first_id++; $first_count++; } else { $sth=$dbh->Query("insert into $secondtable values ($second_id,'This is entry $i')") || die "Got error on insert: $Mysql::db_errstr\n"; die "Row not inserted, aborting\n" if ($sth->affected_rows != 1); $second_id++ if (rand(10) <= 1); # Don't always count it up $second_count++; } print "Write: $i\n" if ($i % 1000 == 0); } print "Writing done ($first_count $second_count)\n";}else{ $dbh = Mysql->Connect($host) || die "Can't connect: $Mysql::db_errstr\n"; $dbh->SelectDB($test_db) || die "Can't use database $test_db: $Mysql::db_errstr\n"; $locked=$found=0; print "Reading started\n"; for ($i=1 ; $i <= $test_count ; $i++) { $id=int(rand($test_count)/3)+1; $sth=$dbh->Query("select count(*) from $firsttable,$secondtable where $firsttable.id = $secondtable.id and $firsttable.id=$id") || die "Got error on select: $Mysql::db_errstr\n"; $found++ if ($sth->numrows); if ($i % 1000 == 0) { print "Read: $i Found: $found\n"; if ($found) { $locked=1-$locked; if ($locked) { $sth=$dbh->Query("lock tables $firsttable write,$secondtable write"); } $sth=$dbh->Query("alter table $firsttable CHANGE id id int(6) not null") || die "Got error on ALTER TABLE: $Mysql::db_errstr\n"; $sth=$dbh->Query("alter table $secondtable CHANGE info info char(32) not null") || die "Got error on ALTER TABLE: $Mysql::db_errstr\n"; if ($locked) { $sth=$dbh->Query("unlock tables"); } } } } print "Reading done Found: $found\n";}
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