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-Implement emulated autocommit for SQLite backend. Mixing and matching autocommit semantics was creating a deadlock. Emulated autocomment does not guarantee rollback to go back as far as one may expect

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git-svn-id: https://svn.code.sf.net/p/xcat/code/xcat-core/trunk@4374 8638fb3e-16cb-4fca-ae20-7b5d299a9bcd
This commit is contained in:
jbjohnso 2009-10-13 19:37:41 +00:00
parent edd7d19f6c
commit 4fb91472c7
1 changed files with 35 additions and 6 deletions
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41
perl-xCAT/xCAT/Table.pm
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@ -24,6 +24,13 @@
#Some known weird behaviors
#creating new sqlite db files when only requested to read non-existant table, easy to fix,
#class xcattable
#FYI on emulated AutoCommit:
#SQLite specific behavior has Table layer implementing AutoCommit. There
#is a significant limitation, 'rollback' may not roll all the way back
#if an intermediate transaction occured on the same table
#TODO: short term, have tabutils implement it's own rollback (the only consumer)
#TODO: longer term, either figure out a way to properly implement it or
# document it as a limitation for SQLite configurations
package xCAT::Table;
use xCAT::MsgUtils;
use Sys::Syslog;
@ -507,6 +514,7 @@ sub new
my $create = 1;
if (exists($otherargs{'-create'}) && ($otherargs{'-create'}==0)) {$create = 0;}
$self->{autocommit} = $otherargs{'-autocommit'};
$self->{realautocommit} = $self->{autocommit}; #Assume we let the DB do the work, i.e. the autocommit is either not used or is not emulated by Table.pm
unless (defined($self->{autocommit}))
{
$self->{autocommit} = 1;
@ -531,6 +539,7 @@ sub new
if ($xcatcfg =~ /^SQLite:/)
{
$self->{backend_type} = 'sqlite';
$self->{realautocommit} = 0; #We will emulate autocommit if autocommit is requested
my @path = split(':', $xcatcfg, 2);
unless (-e $path[1] . "/" . $self->{tabname} . ".sqlite" || $create)
{
@ -554,13 +563,13 @@ sub new
#return undef;
}
my $oldumask= umask 0077;
unless ($::XCAT_DBHS->{$self->{connstring},$self->{dbuser},$self->{dbpass},$self->{autocommit}}) { #= $self->{tabname};
$::XCAT_DBHS->{$self->{connstring},$self->{dbuser},$self->{dbpass},$self->{autocommit}} =
DBI->connect($self->{connstring}, $self->{dbuser}, $self->{dbpass}, {AutoCommit => $self->{autocommit}});
unless ($::XCAT_DBHS->{$self->{connstring},$self->{dbuser},$self->{dbpass},$self->{realautocommit}}) { #= $self->{tabname};
$::XCAT_DBHS->{$self->{connstring},$self->{dbuser},$self->{dbpass},$self->{realautocommit}} =
DBI->connect($self->{connstring}, $self->{dbuser}, $self->{dbpass}, {AutoCommit => $self->{realautocommit}});
}
umask $oldumask;
$self->{dbh} = $::XCAT_DBHS->{$self->{connstring},$self->{dbuser},$self->{dbpass},$self->{autocommit}};
$self->{dbh} = $::XCAT_DBHS->{$self->{connstring},$self->{dbuser},$self->{dbpass},$self->{realautocommit}};
#Store the Table object reference as afflicted by changes to the DBH
#This for now is ok, as either we aren't in DB worker mode, in which case this structure would be short lived...
#or we are in db worker mode, in which case Table objects live indefinitely
@ -584,6 +593,7 @@ sub new
$xCAT::Schema::tabspec{$self->{tabname}},
$xcatcfg);
$self->{dbh}->do($str);
$self->{dbh}->commit;
}
else { return undef; }
}
@ -754,6 +764,9 @@ sub updateschema
my $stmt =
"ALTER TABLE " . $self->{tabname} . " ADD $dcol $datatype";
$self->{dbh}->do($stmt);
if ($self->{autocommit} and not $self->{realautocommit}) {
$self->{dbh}->commit;
}
}
}
@ -845,6 +858,9 @@ sub updateschema
$str = "DROP TABLE $btn";
$self->{dbh}->do($str);
}
if ($self->{autocommit} and not $self->{realautocommit}) {
$self->{dbh}->commit;
}
}
}
}
@ -987,6 +1003,10 @@ sub addAttribs
xCAT::NotifHandler->notify("a", $self->{tabname}, [0],
\%new_notif_data);
}
if ($self->{autocommit} and not $self->{realautocommit}) {
$self->{dbh}->commit();
}
$sth->finish();
}
@ -1205,7 +1225,10 @@ sub setAttribs
{
return (undef, $sth->errstr);
}
$sth->finish;
$sth->finish;
if ($self->{autocommit} and not $self->{realautocommit}) {
$self->{dbh}->commit;
}
}
else
{
@ -1248,7 +1271,10 @@ sub setAttribs
{
return (undef, $sth->errstr);
}
$sth->finish;
$sth->finish;
if ($self->{autocommit} and not $self->{realautocommit}) {
$self->{dbh}->commit();
}
}
#notify the interested parties
@ -1365,6 +1391,9 @@ sub setAttribsWhere
\@notif_data, \%new_notif_data);
}
$sth->finish;
if ($self->{autocommit} and not $self->{realautocommit}) {
$self->{dbh}->commit;
}
return 0;
}