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Comparing BDB/BDB.pm (file contents):
Revision 1.23 by root, Mon Dec 10 04:45:52 2007 UTC vs.
Revision 1.41 by root, Wed Jul 9 12:15:36 2008 UTC

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
32 # automatic event loop intergration with AnyEvent:
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:
107use strict 'vars'; 109use strict 'vars';
108 110
109use base 'Exporter'; 111use base 'Exporter';
110 112
111BEGIN { 113BEGIN {
112 our $VERSION = '1.3'; 114 our $VERSION = '1.6';
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 db_env_dbrename db_env_dbremove
117 db_open db_close db_compact db_sync db_put db_get db_pget db_del db_key_range 119 db_open db_close db_compact db_sync db_upgrade
120 db_put db_get db_pget db_del db_key_range
118 db_txn_commit db_txn_abort db_txn_finish 121 db_txn_commit db_txn_abort db_txn_finish
119 db_c_close db_c_count db_c_put db_c_get db_c_pget db_c_del 122 db_c_close db_c_count db_c_put db_c_get db_c_pget db_c_del
120 db_sequence_open db_sequence_close 123 db_sequence_open db_sequence_close
121 db_sequence_get db_sequence_remove 124 db_sequence_get db_sequence_remove
122 ); 125 );
130 133
131 require XSLoader; 134 require XSLoader;
132 XSLoader::load ("BDB", $VERSION); 135 XSLoader::load ("BDB", $VERSION);
133} 136}
134 137
138=head2 WIN32 FILENAMES/DATABASE NAME MESS
139
140Perl on Win32 supports only ASCII filenames (the reason is that it abuses
141an internal flag to store wether a filename is Unicode or ANSI, but that
142flag is used for somethign else in the perl core, so there is no way to
143detect wether a filename is ANSI or Unicode-encoded). The BDB module
144tries to work around this issue by assuming that the filename is an ANSI
145filename and BDB was built for unicode support.
146
135=head2 BERKELEYDB FUNCTIONS 147=head2 BERKELEYDB FUNCTIONS
136 148
137All of these are functions. The create functions simply return a new 149All of these are functions. The create functions simply return a new
138object and never block. All the remaining functions all take an optional 150object and never block. All the remaining functions take an optional
139callback as last argument that gets passed the return value. If it is 151callback as last argument. If it is missing, then the function will be
140missing, then the function will be executed synchronously, and the return 152executed synchronously. In both cases, C<$!> will reflect the return value
141value is returned as normally. 153of the function.
142 154
143BDB functions that cannot block (mostly functions that manipulate 155BDB functions that cannot block (mostly functions that manipulate
144settings) are method calls on the relevant objects, so the rule of thumb 156settings) are method calls on the relevant objects, so the rule of thumb
145is: if its a method, its not blocking, if its a function, it takes a 157is: if it's a method, it's not blocking, if it's a function, it takes a
146callback as last argument. 158callback as last argument.
147 159
148In the following, C<$int> signifies an integer return value, 160In the following, C<$int> signifies an integer return value,
149C<octetstring> is a "binary string" (i.e. a perl string with no character 161C<bdb_filename> is a "filename" (octets on unix, madness on windows),
150indices >255), C<U32> is an unsigned 32 bit integer, C<int> is some 162C<U32> is an unsigned 32 bit integer, C<int> is some integer, C<NV> is a
151integer, C<NV> is a floating point value. 163floating point value.
152 164
153The C<SV *> types are generic perl scalars (for input and output of data 165Most C<SV *> types are generic perl scalars (for input and output of data
154values), and the C<SV *callback> is the optional callback function to call 166values).
155when the request is completed.
156 167
157The various C<DB_ENV> etc. arguments are handles return by 168The various C<DB_ENV> etc. arguments are handles return by
158C<db_env_create>, C<db_create>, C<txn_begin> and so on. If they have an 169C<db_env_create>, C<db_create>, C<txn_begin> and so on. If they have an
159appended C<_ornull> this means they are optional and you can pass C<undef> 170appended C<_ornull> this means they are optional and you can pass C<undef>
160for them, resulting a NULL pointer on the C level. 171for them, resulting a NULL pointer on the C level.
161 172
173The C<SV *callback> is the optional callback function to call when the
174request is completed. This last callback argument is special: the callback
175is simply the last argument passed. If there are "optional" arguments
176before the callback they can be left out. The callback itself can be left
177out or specified as C<undef>, in which case the function will be executed
178synchronously.
179
180For example, C<db_env_txn_checkpoint> usually is called with all integer
181arguments zero. These can be left out, so all of these specify a call
182to C<< DB_ENV->txn_checkpoint >>, to be executed asynchronously with a
183callback to be called:
184
185 db_env_txn_checkpoint $db_env, 0, 0, 0, sub { };
186 db_env_txn_checkpoint $db_env, 0, 0, sub { };
187 db_env_txn_checkpoint $db_env, sub { };
188
189While these all specify a call to C<< DB_ENV->txn_checkpoint >> to be
190executed synchronously:
191
192 db_env_txn_checkpoint $db_env, 0, 0, 0, undef;
193 db_env_txn_checkpoint $db_env, 0, 0, 0;
194 db_env_txn_checkpoint $db_env, 0;
195
162=head3 BDB functions 196=head3 BDB functions
163 197
164Functions in the BDB namespace, exported by default: 198Functions in the BDB namespace, exported by default:
165 199
166 $env = db_env_create (U32 env_flags = 0) 200 $env = db_env_create (U32 env_flags = 0)
167 flags: RPCCLIENT 201 flags: RPCCLIENT
168 202
169 db_env_open (DB_ENV *env, octetstring db_home, U32 open_flags, int mode, SV *callback = &PL_sv_undef) 203 db_env_open (DB_ENV *env, bdb_filename db_home, U32 open_flags, int mode, SV *callback = &PL_sv_undef)
170 open_flags: INIT_CDB INIT_LOCK INIT_LOG INIT_MPOOL INIT_REP INIT_TXN RECOVER RECOVER_FATAL USE_ENVIRON USE_ENVIRON_ROOT CREATE LOCKDOWN PRIVATE REGISTER SYSTEM_MEM 204 open_flags: INIT_CDB INIT_LOCK INIT_LOG INIT_MPOOL INIT_REP INIT_TXN RECOVER RECOVER_FATAL USE_ENVIRON USE_ENVIRON_ROOT CREATE LOCKDOWN PRIVATE REGISTER SYSTEM_MEM
171 db_env_close (DB_ENV *env, U32 flags = 0, SV *callback = &PL_sv_undef) 205 db_env_close (DB_ENV *env, U32 flags = 0, SV *callback = &PL_sv_undef)
172 db_env_txn_checkpoint (DB_ENV *env, U32 kbyte = 0, U32 min = 0, U32 flags = 0, SV *callback = &PL_sv_undef) 206 db_env_txn_checkpoint (DB_ENV *env, U32 kbyte = 0, U32 min = 0, U32 flags = 0, SV *callback = &PL_sv_undef)
173 flags: FORCE 207 flags: FORCE
174 db_env_lock_detect (DB_ENV *env, U32 flags = 0, U32 atype = DB_LOCK_DEFAULT, SV *dummy = 0, SV *callback = &PL_sv_undef) 208 db_env_lock_detect (DB_ENV *env, U32 flags = 0, U32 atype = DB_LOCK_DEFAULT, SV *dummy = 0, SV *callback = &PL_sv_undef)
175 atype: LOCK_DEFAULT LOCK_EXPIRE LOCK_MAXLOCKS LOCK_MAXWRITE LOCK_MINLOCKS LOCK_MINWRITE LOCK_OLDEST LOCK_RANDOM LOCK_YOUNGEST 209 atype: LOCK_DEFAULT LOCK_EXPIRE LOCK_MAXLOCKS LOCK_MAXWRITE LOCK_MINLOCKS LOCK_MINWRITE LOCK_OLDEST LOCK_RANDOM LOCK_YOUNGEST
176 db_env_memp_sync (DB_ENV *env, SV *dummy = 0, SV *callback = &PL_sv_undef) 210 db_env_memp_sync (DB_ENV *env, SV *dummy = 0, SV *callback = &PL_sv_undef)
177 db_env_memp_trickle (DB_ENV *env, int percent, SV *dummy = 0, SV *callback = &PL_sv_undef) 211 db_env_memp_trickle (DB_ENV *env, int percent, SV *dummy = 0, SV *callback = &PL_sv_undef)
212 db_env_dbremove (DB_ENV *env, DB_TXN_ornull *txnid, bdb_filename file, bdb_filename database, U32 flags = 0, SV *callback = &PL_sv_undef)
213 db_env_dbrename (DB_ENV *env, DB_TXN_ornull *txnid, bdb_filename file, bdb_filename database, bdb_filename newname, U32 flags = 0, SV *callback = &PL_sv_undef)
178 214
179 $db = db_create (DB_ENV *env = 0, U32 flags = 0) 215 $db = db_create (DB_ENV *env = 0, U32 flags = 0)
180 flags: XA_CREATE 216 flags: XA_CREATE
181 217
182 db_open (DB *db, DB_TXN_ornull *txnid, octetstring file, octetstring database, int type, U32 flags, int mode, SV *callback = &PL_sv_undef) 218 db_open (DB *db, DB_TXN_ornull *txnid, bdb_filename file, bdb_filename database, int type, U32 flags, int mode, SV *callback = &PL_sv_undef)
183 flags: AUTO_COMMIT CREATE EXCL MULTIVERSION NOMMAP RDONLY READ_UNCOMMITTED THREAD TRUNCATE 219 flags: AUTO_COMMIT CREATE EXCL MULTIVERSION NOMMAP RDONLY READ_UNCOMMITTED THREAD TRUNCATE
184 db_close (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) 220 db_close (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef)
185 flags: DB_NOSYNC 221 flags: DB_NOSYNC
222 db_upgrade (DB *db, bdb_filename file, U32 flags = 0, SV *callback = &PL_sv_undef)
186 db_compact (DB *db, DB_TXN_ornull *txn = 0, SV *start = 0, SV *stop = 0, SV *unused1 = 0, U32 flags = DB_FREE_SPACE, SV *unused2 = 0, SV *callback = &PL_sv_undef) 223 db_compact (DB *db, DB_TXN_ornull *txn = 0, SV *start = 0, SV *stop = 0, SV *unused1 = 0, U32 flags = DB_FREE_SPACE, SV *unused2 = 0, SV *callback = &PL_sv_undef)
187 flags: FREELIST_ONLY FREE_SPACE 224 flags: FREELIST_ONLY FREE_SPACE
188 db_sync (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) 225 db_sync (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef)
189 db_key_range (DB *db, DB_TXN_ornull *txn, SV *key, SV *key_range, U32 flags = 0, SV *callback = &PL_sv_undef) 226 db_key_range (DB *db, DB_TXN_ornull *txn, SV *key, SV *key_range, U32 flags = 0, SV *callback = &PL_sv_undef)
190 db_put (DB *db, DB_TXN_ornull *txn, SV *key, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) 227 db_put (DB *db, DB_TXN_ornull *txn, SV *key, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef)
263 $int = $env->set_data_dir (const char *dir) 300 $int = $env->set_data_dir (const char *dir)
264 $int = $env->set_tmp_dir (const char *dir) 301 $int = $env->set_tmp_dir (const char *dir)
265 $int = $env->set_lg_dir (const char *dir) 302 $int = $env->set_lg_dir (const char *dir)
266 $int = $env->set_shm_key (long shm_key) 303 $int = $env->set_shm_key (long shm_key)
267 $int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0) 304 $int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0)
268 $int = $env->set_flags (U32 flags, int onoff) 305 $int = $env->set_flags (U32 flags, int onoff = 1)
306 $int = $env->log_set_config (U32 flags, int onoff = 1) [v4.7]
307 $int = $env->set_intermediate_dir_mode (const char *modestring) [v4.7]
269 $env->set_errfile (FILE *errfile = 0) 308 $env->set_errfile (FILE *errfile = 0)
270 $env->set_msgfile (FILE *msgfile = 0) 309 $env->set_msgfile (FILE *msgfile = 0)
271 $int = $env->set_verbose (U32 which, int onoff = 1) 310 $int = $env->set_verbose (U32 which, int onoff = 1)
272 $int = $env->set_encrypt (const char *password, U32 flags = 0) 311 $int = $env->set_encrypt (const char *password, U32 flags = 0)
273 $int = $env->set_timeout (NV timeout_seconds, U32 flags = SET_TXN_TIMEOUT) 312 $int = $env->set_timeout (NV timeout_seconds, U32 flags = SET_TXN_TIMEOUT)
386 DESTROY (DBC_ornull *dbc) 425 DESTROY (DBC_ornull *dbc)
387 CODE: 426 CODE:
388 if (dbc) 427 if (dbc)
389 dbc->c_close (dbc); 428 dbc->c_close (dbc);
390 429
430 $int = $cursor->set_priority ($priority = PRIORITY_*)
431
391=head4 Example: 432=head4 Example:
392 433
393 my $c = $db->cursor; 434 my $c = $db->cursor;
394 435
395 for (;;) { 436 for (;;) {
433=item $msg = BDB::strerror [$errno] 474=item $msg = BDB::strerror [$errno]
434 475
435Returns the string corresponding to the given errno value. If no argument 476Returns the string corresponding to the given errno value. If no argument
436is given, use C<$!>. 477is given, use C<$!>.
437 478
479Note that the BDB module also patches the C<$!> variable directly, so you
480should be able to get a bdb error string by simply stringifying C<$!>.
481
438=item $fileno = BDB::poll_fileno 482=item $fileno = BDB::poll_fileno
439 483
440Return the I<request result pipe file descriptor>. This filehandle must be 484Return the I<request result pipe file descriptor>. This filehandle must be
441polled for reading by some mechanism outside this module (e.g. Event or 485polled for reading by some mechanism outside this module (e.g. Event or
442select, see below or the SYNOPSIS). If the pipe becomes readable you have 486select, see below or the SYNOPSIS). If the pipe becomes readable you have
518 BDB::poll_wait, BDB::poll_cb 562 BDB::poll_wait, BDB::poll_cb
519 while BDB::nreqs; 563 while BDB::nreqs;
520 564
521=back 565=back
522 566
567=head3 VERSION CHECKING
568
569BerkeleyDB comes in various versions, many of them have minor
570incompatibilities. This means that traditional "at least version x.x"
571checks are often not sufficient.
572
573Example: set the log_autoremove option in a way compatible with <v.47 and
574v4.7. Note the use of & on the constants to avoid triggering a compiletime
575bug when the symbol isn't available.
576
577 $DB_ENV->set_flags (&BDB::LOG_AUTOREMOVE ) if BDB::VERSION v0, v4.7;
578 $DB_ENV->log_set_config (&BDB::LOG_AUTO_REMOVE) if BDB::VERSION v4.7;
579
580=over 4
581
582=item BDB::VERSION
583
584The C<BDB::VERSION> function, when called without arguments, returns the
585Berkeley DB version as a v-string (usually with 3 components). You should
586use C<lt> and C<ge> operators exclusively to make comparisons.
587
588Example: check for at least version 4.7.
589
590 BDB::VERSION ge v4.7 or die;
591
592=item BDB::VERSION min-version
593
594Returns true if the BDB version is at least the given version (specified
595as a v-string), false otherwise.
596
597Example: check for at least version 4.5.
598
599 BDB::VERSION v4.7 or die;
600
601=item BDB::VERSION min-version, max-version
602
603Returns true of the BDB version is at least version C<min-version> (specify C<undef> or C<v0> for any minimum version)
604and less then C<max-version>.
605
606Example: check wether version is strictly less then v4.7.
607
608 BDB::VERSION v0, v4.7
609 or die "version 4.7 is not yet supported";
610
611=back
612
613=cut
614
615sub VERSION {
616 if (@_ > 0) {
617 return undef if VERSION_v lt $_[0];
618 if (@_ > 1) {
619 return undef if VERSION_v ge $_[1];
620 }
621 }
622
623 VERSION_v
624}
625
523=head3 CONTROLLING THE NUMBER OF THREADS 626=head3 CONTROLLING THE NUMBER OF THREADS
524 627
525=over 4 628=over 4
526 629
527=item BDB::min_parallel $nthreads 630=item BDB::min_parallel $nthreads
593 696
594=item BDB::set_sync_prepare $cb 697=item BDB::set_sync_prepare $cb
595 698
596Sets a callback that is called whenever a request is created without an 699Sets a callback that is called whenever a request is created without an
597explicit callback. It has to return two code references. The first is used 700explicit callback. It has to return two code references. The first is used
598as the request callback, and the second is called to wait until the first 701as the request callback (it should save the return status), and the second
702is called to wait until the first callback has been called (it must set
703C<$!> to the return status).
704
705This mechanism can be used to include BDB into other event mechanisms,
706such as L<AnyEvent::BDB> or L<Coro::BDB>.
707
599callback has been called. The default implementation works like this: 708The default implementation works like this:
600 709
601 sub { 710 sub {
602 my $status; 711 my $status;
603 ( 712 (
604 sub { $status = $! }, 713 sub { $status = $! },
605 sub { BDB::poll while !defined $status; $! = $status }, 714 sub { BDB::poll while !defined $status; $! = $status },
606 ) 715 )
607 } 716 }
717
718It simply blocks the process till the request has finished and then sets
719C<$!> to the return value. This means that if you don't use a callback,
720BDB will simply fall back to synchronous operations.
608 721
609=back 722=back
610 723
611=head3 STATISTICAL INFORMATION 724=head3 STATISTICAL INFORMATION
612 725
669 782
670In short: the parent will, after a short pause, continue as if fork had 783In short: the parent will, after a short pause, continue as if fork had
671not been called, while the child will act as if BDB has not been used 784not been called, while the child will act as if BDB has not been used
672yet. 785yet.
673 786
787Win32 note: there is no fork on win32, and perls emulation of it is too
788broken to be supported, so do not use BDB in a windows pseudo-fork, better
789yet, switch to a more capable platform.
790
674=head2 MEMORY USAGE 791=head2 MEMORY USAGE
675 792
676Per-request usage: 793Per-request usage:
677 794
678Each aio request uses - depending on your architecture - around 100-200 795Each aio request uses - depending on your architecture - around 100-200
699 TXN_DEADLOCK flag will be set on the transaction. See C<db_txn_finish>, 816 TXN_DEADLOCK flag will be set on the transaction. See C<db_txn_finish>,
700 above. 817 above.
701 818
702=head1 SEE ALSO 819=head1 SEE ALSO
703 820
704L<Coro::BDB>, L<IO::AIO>. 821L<AnyEvent::BDB> (event loop integration), L<Coro::BDB> (more natural
822syntax), L<IO::AIO> (nice to have).
705 823
706=head1 AUTHOR 824=head1 AUTHOR
707 825
708 Marc Lehmann <schmorp@schmorp.de> 826 Marc Lehmann <schmorp@schmorp.de>
709 http://home.schmorp.de/ 827 http://home.schmorp.de/

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