… | |
… | |
24 | db_put $db, undef, "key", "data", 0, sub { |
24 | db_put $db, undef, "key", "data", 0, sub { |
25 | db_del $db, undef, "key"; |
25 | db_del $db, undef, "key"; |
26 | }; |
26 | }; |
27 | db_sync $db; |
27 | db_sync $db; |
28 | |
28 | |
29 | # automatic result processing with AnyEvent: |
29 | # when you also use Coro, management is easy: |
30 | our $FH; open $FH, "<&=" . BDB::poll_fileno; |
30 | use Coro::BDB; |
31 | our $WATCHER = AnyEvent->io (fh => $FH, poll => 'r', cb => \&BDB::poll_cb); |
31 | |
|
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32 | # automatic event loop intergration with AnyEvent: |
|
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33 | use AnyEvent::BDB; |
32 | |
34 | |
33 | # automatic result processing with EV: |
35 | # automatic result processing with EV: |
34 | my $WATCHER = EV::io BDB::poll_fileno, EV::READ, \&BDB::poll_cb; |
36 | my $WATCHER = EV::io BDB::poll_fileno, EV::READ, \&BDB::poll_cb; |
35 | |
37 | |
36 | # with Glib: |
38 | # with Glib: |
… | |
… | |
107 | use strict 'vars'; |
109 | use strict 'vars'; |
108 | |
110 | |
109 | use base 'Exporter'; |
111 | use base 'Exporter'; |
110 | |
112 | |
111 | BEGIN { |
113 | BEGIN { |
112 | our $VERSION = '1.3'; |
114 | our $VERSION = '1.5'; |
113 | |
115 | |
114 | our @BDB_REQ = qw( |
116 | our @BDB_REQ = qw( |
115 | db_env_open db_env_close db_env_txn_checkpoint db_env_lock_detect |
117 | db_env_open db_env_close db_env_txn_checkpoint db_env_lock_detect |
116 | db_env_memp_sync db_env_memp_trickle |
118 | db_env_memp_sync db_env_memp_trickle |
117 | db_open db_close db_compact db_sync db_upgrade |
119 | db_open db_close db_compact db_sync db_upgrade |
… | |
… | |
131 | |
133 | |
132 | require XSLoader; |
134 | require XSLoader; |
133 | XSLoader::load ("BDB", $VERSION); |
135 | XSLoader::load ("BDB", $VERSION); |
134 | } |
136 | } |
135 | |
137 | |
|
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138 | =head2 WIN32 FILENAMES/DATABASE NAME MESS |
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139 | |
|
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140 | Perl on Win32 supports only ASCII filenames (the reason is that it abuses |
|
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141 | an internal flag to store wether a filename is Unicode or ANSI, but that |
|
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142 | flag is used for somethign else in the perl core, so there is no way to |
|
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143 | detect wether a filename is ANSI or Unicode-encoded). The BDB module |
|
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144 | tries to work around this issue by assuming that the filename is an ANSI |
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145 | filename and BDB was built for unicode support. |
|
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146 | |
136 | =head2 BERKELEYDB FUNCTIONS |
147 | =head2 BERKELEYDB FUNCTIONS |
137 | |
148 | |
138 | All of these are functions. The create functions simply return a new |
149 | All of these are functions. The create functions simply return a new |
139 | object and never block. All the remaining functions all take an optional |
150 | object and never block. All the remaining functions take an optional |
140 | callback as last argument. If it is missing, then the function will be |
151 | callback as last argument. If it is missing, then the function will be |
141 | executed synchronously. In both cases, C<$!> will reflect the return value |
152 | executed synchronously. In both cases, C<$!> will reflect the return value |
142 | of the function. |
153 | of the function. |
143 | |
154 | |
144 | BDB functions that cannot block (mostly functions that manipulate |
155 | BDB functions that cannot block (mostly functions that manipulate |
145 | settings) are method calls on the relevant objects, so the rule of thumb |
156 | settings) are method calls on the relevant objects, so the rule of thumb |
146 | is: if its a method, its not blocking, if its a function, it takes a |
157 | is: if it's a method, it's not blocking, if it's a function, it takes a |
147 | callback as last argument. |
158 | callback as last argument. |
148 | |
159 | |
149 | In the following, C<$int> signifies an integer return value, |
160 | In the following, C<$int> signifies an integer return value, |
150 | C<octetstring> is a "binary string" (i.e. a perl string with no character |
161 | C<octetstring> is a "binary string" (i.e. a perl string with no character |
151 | indices >255), C<U32> is an unsigned 32 bit integer, C<int> is some |
162 | indices >255), C<U32> is an unsigned 32 bit integer, C<int> is some |
… | |
… | |
388 | DESTROY (DBC_ornull *dbc) |
399 | DESTROY (DBC_ornull *dbc) |
389 | CODE: |
400 | CODE: |
390 | if (dbc) |
401 | if (dbc) |
391 | dbc->c_close (dbc); |
402 | dbc->c_close (dbc); |
392 | |
403 | |
|
|
404 | $int = $cursor->set_priority ($priority = PRIORITY_*) |
|
|
405 | |
393 | =head4 Example: |
406 | =head4 Example: |
394 | |
407 | |
395 | my $c = $db->cursor; |
408 | my $c = $db->cursor; |
396 | |
409 | |
397 | for (;;) { |
410 | for (;;) { |
… | |
… | |
435 | =item $msg = BDB::strerror [$errno] |
448 | =item $msg = BDB::strerror [$errno] |
436 | |
449 | |
437 | Returns the string corresponding to the given errno value. If no argument |
450 | Returns the string corresponding to the given errno value. If no argument |
438 | is given, use C<$!>. |
451 | is given, use C<$!>. |
439 | |
452 | |
|
|
453 | Note that the BDB module also patches the C<$!> variable directly, so you |
|
|
454 | should be able to get a bdb error string by simply stringifying C<$!>. |
|
|
455 | |
440 | =item $fileno = BDB::poll_fileno |
456 | =item $fileno = BDB::poll_fileno |
441 | |
457 | |
442 | Return the I<request result pipe file descriptor>. This filehandle must be |
458 | Return the I<request result pipe file descriptor>. This filehandle must be |
443 | polled for reading by some mechanism outside this module (e.g. Event or |
459 | polled for reading by some mechanism outside this module (e.g. Event or |
444 | select, see below or the SYNOPSIS). If the pipe becomes readable you have |
460 | select, see below or the SYNOPSIS). If the pipe becomes readable you have |
… | |
… | |
595 | |
611 | |
596 | =item BDB::set_sync_prepare $cb |
612 | =item BDB::set_sync_prepare $cb |
597 | |
613 | |
598 | Sets a callback that is called whenever a request is created without an |
614 | Sets a callback that is called whenever a request is created without an |
599 | explicit callback. It has to return two code references. The first is used |
615 | explicit callback. It has to return two code references. The first is used |
600 | as the request callback, and the second is called to wait until the first |
616 | as the request callback (it should save the return status), and the second |
|
|
617 | is called to wait until the first callback has been called (it must set |
|
|
618 | C<$!> to the return status). |
|
|
619 | |
|
|
620 | This mechanism can be used to include BDB into other event mechanisms, |
|
|
621 | such as L<AnyEvent::BDB> or L<Coro::BDB>. |
|
|
622 | |
601 | callback has been called. The default implementation works like this: |
623 | The default implementation works like this: |
602 | |
624 | |
603 | sub { |
625 | sub { |
604 | my $status; |
626 | my $status; |
605 | ( |
627 | ( |
606 | sub { $status = $! }, |
628 | sub { $status = $! }, |
607 | sub { BDB::poll while !defined $status; $! = $status }, |
629 | sub { BDB::poll while !defined $status; $! = $status }, |
608 | ) |
630 | ) |
609 | } |
631 | } |
|
|
632 | |
|
|
633 | It simply blocks the process till the request has finished and then sets |
|
|
634 | C<$!> to the return value. This means that if you don't use a callback, |
|
|
635 | BDB will simply fall back to synchronous operations. |
610 | |
636 | |
611 | =back |
637 | =back |
612 | |
638 | |
613 | =head3 STATISTICAL INFORMATION |
639 | =head3 STATISTICAL INFORMATION |
614 | |
640 | |
… | |
… | |
671 | |
697 | |
672 | In short: the parent will, after a short pause, continue as if fork had |
698 | In short: the parent will, after a short pause, continue as if fork had |
673 | not been called, while the child will act as if BDB has not been used |
699 | not been called, while the child will act as if BDB has not been used |
674 | yet. |
700 | yet. |
675 | |
701 | |
|
|
702 | Win32 note: there is no fork on win32, and perls emulation of it is too |
|
|
703 | broken to be supported, so do not use BDB in a windows pseudo-fork, better |
|
|
704 | yet, switch to a more capable platform. |
|
|
705 | |
676 | =head2 MEMORY USAGE |
706 | =head2 MEMORY USAGE |
677 | |
707 | |
678 | Per-request usage: |
708 | Per-request usage: |
679 | |
709 | |
680 | Each aio request uses - depending on your architecture - around 100-200 |
710 | Each aio request uses - depending on your architecture - around 100-200 |
… | |
… | |
701 | TXN_DEADLOCK flag will be set on the transaction. See C<db_txn_finish>, |
731 | TXN_DEADLOCK flag will be set on the transaction. See C<db_txn_finish>, |
702 | above. |
732 | above. |
703 | |
733 | |
704 | =head1 SEE ALSO |
734 | =head1 SEE ALSO |
705 | |
735 | |
706 | L<Coro::BDB>, L<IO::AIO>. |
736 | L<AnyEvent::BDB> (event loop integration), L<Coro::BDB> (more natural |
|
|
737 | syntax), L<IO::AIO> (nice to have). |
707 | |
738 | |
708 | =head1 AUTHOR |
739 | =head1 AUTHOR |
709 | |
740 | |
710 | Marc Lehmann <schmorp@schmorp.de> |
741 | Marc Lehmann <schmorp@schmorp.de> |
711 | http://home.schmorp.de/ |
742 | http://home.schmorp.de/ |