This causes an infinite loop, because for each iteration, Perl is calling
FETCH() on the $db handle, resulting in a "new" hash for foo every time, so
it effectively keeps returning the first key over and over again. Instead,
-assign a temporary variable to C<$db->{foo}>, then pass that to each().
+assign a temporary variable to C<<$db->{foo}>>, then pass that to each().
=head2 Arrays
my $copy = $db->clone();
-B<Note>: Since clone() here is cloning the object, not the database location, any
-modifications to either $db or $copy will be visible to both.
+B<Note>: Since clone() here is cloning the object, not the database location,
+any modifications to either $db or $copy will be visible to both.
+
+=head2 Stale References
+
+If you take a reference to an array or hash from the database, it is tied
+to the database itself. This means that if the datum in question is subsequentl
+an invalid location and unpredictable things will happen if you try to use
+it.
+
+So a seemingly innocuous piece of code like this:
+
+ my %hash = %{ $db->{some_hash} };
+
+can fail if another process deletes or clobbers C<< $db->{some_hash} >>
+while the data are being extracted, since S<C<%{ ... }>> is not atomic.
+(This actually happened.) The solution is to lock the database before
+reading the data:
+
+ $db->lock_exclusive;
+ my %hash = %{ $db->{some_hash} };
+ $db->unlock;
=head2 Large Arrays
B<NOTE:> This does not affect importing because imports do a walk over the
reference to be imported in order to explicitly leave it untied.
+=head2 Stale References
+
+If you take a reference to an array or hash from the database, it is tied
+to the database itself. This means that if the datum in question is subsequently deleted from the database, the reference to it will point to
+an invalid location and unpredictable things will happen if you try to use
+it.
+
+So a seemingly innocuous piece of code like this:
+
+ my %hash = %{ $db->{some_hash} };
+
+can fail if another process deletes or clobbers C<< $db->{some_hash} >>
+while the data are being extracted, since S<C<%{ ... }>> is not atomic.
+(This actually happened.) The solution is to lock the database before
+reading the data:
+
+ $db->lock_exclusive;
+ my %hash = %{ $db->{some_hash} };
+ $db->unlock;
+
=head1 CODE COVERAGE
L<Devel::Cover> is used to test the code coverage of the tests. Below is the
L<Devel::Cover> report on this distribution's test suite.
- ------------------------------------------ ------ ------ ------ ------ ------
- File stmt bran cond sub total
- ------------------------------------------ ------ ------ ------ ------ ------
- blib/lib/DBM/Deep.pm 97.2 90.9 83.3 100.0 95.4
- blib/lib/DBM/Deep/Array.pm 100.0 95.7 100.0 100.0 99.0
- blib/lib/DBM/Deep/Engine.pm 95.6 84.7 81.6 98.4 92.5
- blib/lib/DBM/Deep/File.pm 97.2 81.6 66.7 100.0 91.9
- blib/lib/DBM/Deep/Hash.pm 100.0 100.0 100.0 100.0 100.0
- Total 96.7 87.5 82.2 99.2 94.1
- ------------------------------------------ ------ ------ ------ ------ ------
+ ---------------------------- ------ ------ ------ ------ ------ ------ ------
+ File stmt bran cond sub pod time total
+ ---------------------------- ------ ------ ------ ------ ------ ------ ------
+ blib/lib/DBM/Deep.pm 100.0 89.1 82.9 100.0 100.0 32.5 98.1
+ blib/lib/DBM/Deep/Array.pm 100.0 94.4 100.0 100.0 100.0 5.2 98.8
+ blib/lib/DBM/Deep/Engine.pm 100.0 92.9 100.0 100.0 100.0 7.4 100.0
+ ...ib/DBM/Deep/Engine/DBI.pm 95.0 73.1 100.0 100.0 100.0 1.5 90.4
+ ...b/DBM/Deep/Engine/File.pm 92.3 78.5 88.9 100.0 100.0 4.9 90.3
+ blib/lib/DBM/Deep/Hash.pm 100.0 100.0 100.0 100.0 100.0 3.8 100.0
+ .../lib/DBM/Deep/Iterator.pm 100.0 n/a n/a 100.0 100.0 0.0 100.0
+ .../DBM/Deep/Iterator/DBI.pm 100.0 100.0 n/a 100.0 100.0 1.2 100.0
+ ...DBM/Deep/Iterator/File.pm 92.5 84.6 n/a 100.0 66.7 0.6 90.0
+ ...erator/File/BucketList.pm 100.0 75.0 n/a 100.0 66.7 0.4 93.8
+ ...ep/Iterator/File/Index.pm 100.0 100.0 n/a 100.0 100.0 0.2 100.0
+ blib/lib/DBM/Deep/Null.pm 87.5 n/a n/a 75.0 n/a 0.0 83.3
+ blib/lib/DBM/Deep/Sector.pm 91.7 n/a n/a 83.3 0.0 6.7 74.4
+ ...ib/DBM/Deep/Sector/DBI.pm 96.8 83.3 n/a 100.0 0.0 1.0 89.8
+ ...p/Sector/DBI/Reference.pm 100.0 95.5 100.0 100.0 0.0 2.2 91.2
+ ...Deep/Sector/DBI/Scalar.pm 100.0 100.0 n/a 100.0 0.0 1.1 92.9
+ ...b/DBM/Deep/Sector/File.pm 96.0 87.5 100.0 92.3 25.0 2.2 91.0
+ ...Sector/File/BucketList.pm 98.2 85.7 83.3 100.0 0.0 3.3 89.4
+ .../Deep/Sector/File/Data.pm 100.0 n/a n/a 100.0 0.0 0.1 90.9
+ ...Deep/Sector/File/Index.pm 100.0 80.0 33.3 100.0 0.0 0.8 83.1
+ .../Deep/Sector/File/Null.pm 100.0 100.0 n/a 100.0 0.0 0.0 91.7
+ .../Sector/File/Reference.pm 100.0 90.0 80.0 100.0 0.0 1.4 91.5
+ ...eep/Sector/File/Scalar.pm 98.4 87.5 n/a 100.0 0.0 0.8 91.9
+ blib/lib/DBM/Deep/Storage.pm 100.0 n/a n/a 100.0 100.0 0.0 100.0
+ ...b/DBM/Deep/Storage/DBI.pm 97.3 70.8 n/a 100.0 38.5 6.7 87.0
+ .../DBM/Deep/Storage/File.pm 96.6 77.1 80.0 95.7 100.0 16.0 91.8
+ Total 99.3 85.2 84.9 99.8 63.3 100.0 97.6
+ ---------------------------- ------ ------ ------ ------ ------ ------ ------
=head1 MORE INFORMATION
projects / dbsrgits/DBM-Deep.git / blobdiff