[ViewVC] Diff of: cvs/BDB/BDB.pm

Comparing BDB/BDB.pm (file contents):
Revision 1.25 by root, Mon Dec 10 21:19:06 2007 UTC vs.
Revision 1.53 by root, Tue Oct 21 02:21:25 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:
…		…
106	no warnings;	108	no warnings;
107	use strict 'vars';	109	use strict 'vars';
108		110
109	use base 'Exporter';	111	use base 'Exporter';
110		112
		113	our $VERSION;
		114
111	BEGIN {	115	BEGIN {
112	our $VERSION = '1.3';	116	$VERSION = '1.81';
113		117
114	our @BDB_REQ = qw(	118	our @BDB_REQ = qw(
115	db_env_open db_env_close db_env_txn_checkpoint db_env_lock_detect	119	db_env_open db_env_close db_env_txn_checkpoint db_env_lock_detect
116	db_env_memp_sync db_env_memp_trickle	120	db_env_memp_sync db_env_memp_trickle db_env_dbrename db_env_dbremove
		121	db_env_log_archive
117	db_open db_close db_compact db_sync db_upgrade	122	db_open db_close db_compact db_sync db_upgrade
118	db_put db_get db_pget db_del db_key_range	123	db_put db_exists db_get db_pget db_del db_key_range
119	db_txn_commit db_txn_abort db_txn_finish	124	db_txn_commit db_txn_abort db_txn_finish
120	db_c_close db_c_count db_c_put db_c_get db_c_pget db_c_del	125	db_c_close db_c_count db_c_put db_c_get db_c_pget db_c_del
121	db_sequence_open db_sequence_close	126	db_sequence_open db_sequence_close
122	db_sequence_get db_sequence_remove	127	db_sequence_get db_sequence_remove
123	);	128	);
…		…
131		136
132	require XSLoader;	137	require XSLoader;
133	XSLoader::load ("BDB", $VERSION);	138	XSLoader::load ("BDB", $VERSION);
134	}	139	}
135		140
136	=head2 BERKELEYDB FUNCTIONS	141	=head1 BERKELEYDB FUNCTIONS
137		142
138	All of these are functions. The create functions simply return a new	143	All of these are functions. The create functions simply return a new
139	object and never block. All the remaining functions all take an optional	144	object and never block. All the remaining functions take an optional
140	callback as last argument. If it is missing, then the function will be	145	callback as last argument. If it is missing, then the function will be
141	executed synchronously. In both cases, C<$!> will reflect the return value	146	executed synchronously. In both cases, C<$!> will reflect the return value
142	of the function.	147	of the function.
143		148
144	BDB functions that cannot block (mostly functions that manipulate	149	BDB functions that cannot block (mostly functions that manipulate
145	settings) are method calls on the relevant objects, so the rule of thumb	150	settings) are method calls on the relevant objects, so the rule of thumb
146	is: if its a method, its not blocking, if its a function, it takes a	151	is: if it's a method, it's not blocking, if it's a function, it takes a
147	callback as last argument.	152	callback as last argument.
148		153
149	In the following, C<$int> signifies an integer return value,	154	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	155	C<bdb_filename> is a "filename" (octets on unix, madness on windows),
151	indices >255), C<U32> is an unsigned 32 bit integer, C<int> is some	156	C<U32> is an unsigned 32 bit integer, C<int> is some integer, C<NV> is a
152	integer, C<NV> is a floating point value.	157	floating point value.
153		158
154	The C<SV *> types are generic perl scalars (for input and output of data	159	Most C<SV *> types are generic perl scalars (for input and output of data
155	values), and the C<SV *callback> is the optional callback function to call	160	values).
156	when the request is completed.
157		161
158	The various C<DB_ENV> etc. arguments are handles return by	162	The various C<DB_ENV> etc. arguments are handles return by
159	C<db_env_create>, C<db_create>, C<txn_begin> and so on. If they have an	163	C<db_env_create>, C<db_create>, C<txn_begin> and so on. If they have an
160	appended C<_ornull> this means they are optional and you can pass C<undef>	164	appended C<_ornull> this means they are optional and you can pass C<undef>
161	for them, resulting a NULL pointer on the C level.	165	for them, resulting a NULL pointer on the C level.
162		166
		167	The C<SV *callback> is the optional callback function to call when the
		168	request is completed. This last callback argument is special: the callback
		169	is simply the last argument passed. If there are "optional" arguments
		170	before the callback they can be left out. The callback itself can be left
		171	out or specified as C<undef>, in which case the function will be executed
		172	synchronously.
		173
		174	For example, C<db_env_txn_checkpoint> usually is called with all integer
		175	arguments zero. These can be left out, so all of these specify a call
		176	to C<< DB_ENV->txn_checkpoint >>, to be executed asynchronously with a
		177	callback to be called:
		178
		179	db_env_txn_checkpoint $db_env, 0, 0, 0, sub { };
		180	db_env_txn_checkpoint $db_env, 0, 0, sub { };
		181	db_env_txn_checkpoint $db_env, sub { };
		182
		183	While these all specify a call to C<< DB_ENV->txn_checkpoint >> to be
		184	executed synchronously:
		185
		186	db_env_txn_checkpoint $db_env, 0, 0, 0, undef;
		187	db_env_txn_checkpoint $db_env, 0, 0, 0;
		188	db_env_txn_checkpoint $db_env, 0;
		189
163	=head3 BDB functions	190	=head2 BDB functions
164		191
165	Functions in the BDB namespace, exported by default:	192	Functions in the BDB namespace, exported by default:
166		193
167	$env = db_env_create (U32 env_flags = 0)	194	$env = db_env_create (U32 env_flags = 0)
168	flags: RPCCLIENT	195	flags: RPCCLIENT
169		196
170	db_env_open (DB_ENV env, octetstring db_home, U32 open_flags, int mode, SV callback = &PL_sv_undef)	197	db_env_open (DB_ENV env, bdb_filename db_home, U32 open_flags, int mode, SV callback = &PL_sv_undef)
171	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	198	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
172	db_env_close (DB_ENV env, U32 flags = 0, SV callback = &PL_sv_undef)	199	db_env_close (DB_ENV env, U32 flags = 0, SV callback = &PL_sv_undef)
173	db_env_txn_checkpoint (DB_ENV env, U32 kbyte = 0, U32 min = 0, U32 flags = 0, SV callback = &PL_sv_undef)	200	db_env_txn_checkpoint (DB_ENV env, U32 kbyte = 0, U32 min = 0, U32 flags = 0, SV callback = &PL_sv_undef)
174	flags: FORCE	201	flags: FORCE
175	db_env_lock_detect (DB_ENV env, U32 flags = 0, U32 atype = DB_LOCK_DEFAULT, SV dummy = 0, SV *callback = &PL_sv_undef)	202	db_env_lock_detect (DB_ENV env, U32 flags = 0, U32 atype = DB_LOCK_DEFAULT, SV dummy = 0, SV *callback = &PL_sv_undef)
176	atype: LOCK_DEFAULT LOCK_EXPIRE LOCK_MAXLOCKS LOCK_MAXWRITE LOCK_MINLOCKS LOCK_MINWRITE LOCK_OLDEST LOCK_RANDOM LOCK_YOUNGEST	203	atype: LOCK_DEFAULT LOCK_EXPIRE LOCK_MAXLOCKS LOCK_MAXWRITE LOCK_MINLOCKS LOCK_MINWRITE LOCK_OLDEST LOCK_RANDOM LOCK_YOUNGEST
177	db_env_memp_sync (DB_ENV env, SV dummy = 0, SV *callback = &PL_sv_undef)	204	db_env_memp_sync (DB_ENV env, SV dummy = 0, SV *callback = &PL_sv_undef)
178	db_env_memp_trickle (DB_ENV env, int percent, SV dummy = 0, SV *callback = &PL_sv_undef)	205	db_env_memp_trickle (DB_ENV env, int percent, SV dummy = 0, SV *callback = &PL_sv_undef)
		206	db_env_dbremove (DB_ENV env, DB_TXN_ornull txnid, bdb_filename file, bdb_filename database, U32 flags = 0, SV *callback = &PL_sv_undef)
		207	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)
		208	db_env_log_archive (DB_ENV env, SV listp, U32 flags = 0, SV *callback = &PL_sv_undef)
179		209
180	$db = db_create (DB_ENV *env = 0, U32 flags = 0)	210	$db = db_create (DB_ENV *env = 0, U32 flags = 0)
181	flags: XA_CREATE	211	flags: XA_CREATE
182		212
183	db_open (DB db, DB_TXN_ornull txnid, octetstring file, octetstring database, int type, U32 flags, int mode, SV *callback = &PL_sv_undef)	213	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)
184	flags: AUTO_COMMIT CREATE EXCL MULTIVERSION NOMMAP RDONLY READ_UNCOMMITTED THREAD TRUNCATE	214	flags: AUTO_COMMIT CREATE EXCL MULTIVERSION NOMMAP RDONLY READ_UNCOMMITTED THREAD TRUNCATE
185	db_close (DB db, U32 flags = 0, SV callback = &PL_sv_undef)	215	db_close (DB db, U32 flags = 0, SV callback = &PL_sv_undef)
186	flags: DB_NOSYNC	216	flags: DB_NOSYNC
187	db_upgrade (DB db, octetstring file, U32 flags = 0, SV callback = &PL_sv_undef)	217	db_upgrade (DB db, bdb_filename file, U32 flags = 0, SV callback = &PL_sv_undef)
188	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)	218	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)
189	flags: FREELIST_ONLY FREE_SPACE	219	flags: FREELIST_ONLY FREE_SPACE
190	db_sync (DB db, U32 flags = 0, SV callback = &PL_sv_undef)	220	db_sync (DB db, U32 flags = 0, SV callback = &PL_sv_undef)
191	db_key_range (DB db, DB_TXN_ornull txn, SV key, SV key_range, U32 flags = 0, SV *callback = &PL_sv_undef)	221	db_key_range (DB db, DB_TXN_ornull txn, SV key, SV key_range, U32 flags = 0, SV *callback = &PL_sv_undef)
192	db_put (DB db, DB_TXN_ornull txn, SV key, SV data, U32 flags = 0, SV *callback = &PL_sv_undef)	222	db_put (DB db, DB_TXN_ornull txn, SV key, SV data, U32 flags = 0, SV *callback = &PL_sv_undef)
193	flags: APPEND NODUPDATA NOOVERWRITE	223	flags: APPEND NODUPDATA NOOVERWRITE
		224	db_exists (DB db, DB_TXN_ornull txn, SV key, U32 flags = 0, SV callback = 0) (v4.6)
194	db_get (DB db, DB_TXN_ornull txn, SV key, SV data, U32 flags = 0, SV *callback = &PL_sv_undef)	225	db_get (DB db, DB_TXN_ornull txn, SV key, SV data, U32 flags = 0, SV *callback = &PL_sv_undef)
195	flags: CONSUME CONSUME_WAIT GET_BOTH SET_RECNO MULTIPLE READ_COMMITTED READ_UNCOMMITTED RMW	226	flags: CONSUME CONSUME_WAIT GET_BOTH SET_RECNO MULTIPLE READ_COMMITTED READ_UNCOMMITTED RMW
196	db_pget (DB db, DB_TXN_ornull txn, SV key, SV pkey, SV data, U32 flags = 0, SV callback = &PL_sv_undef)	227	db_pget (DB db, DB_TXN_ornull txn, SV key, SV pkey, SV data, U32 flags = 0, SV callback = &PL_sv_undef)
197	flags: CONSUME CONSUME_WAIT GET_BOTH SET_RECNO MULTIPLE READ_COMMITTED READ_UNCOMMITTED RMW	228	flags: CONSUME CONSUME_WAIT GET_BOTH SET_RECNO MULTIPLE READ_COMMITTED READ_UNCOMMITTED RMW
198	db_del (DB db, DB_TXN_ornull txn, SV key, U32 flags = 0, SV callback = &PL_sv_undef)	229	db_del (DB db, DB_TXN_ornull txn, SV key, U32 flags = 0, SV callback = &PL_sv_undef)
…		…
215	db_sequence_get (DB_SEQUENCE seq, DB_TXN_ornull txnid, int delta, SV seq_value, U32 flags = DB_TXN_NOSYNC, SV callback = &PL_sv_undef)	246	db_sequence_get (DB_SEQUENCE seq, DB_TXN_ornull txnid, int delta, SV seq_value, U32 flags = DB_TXN_NOSYNC, SV callback = &PL_sv_undef)
216	flags: TXN_NOSYNC	247	flags: TXN_NOSYNC
217	db_sequence_remove (DB_SEQUENCE seq, DB_TXN_ornull txnid = 0, U32 flags = 0, SV *callback = &PL_sv_undef)	248	db_sequence_remove (DB_SEQUENCE seq, DB_TXN_ornull txnid = 0, U32 flags = 0, SV *callback = &PL_sv_undef)
218	flags: TXN_NOSYNC	249	flags: TXN_NOSYNC
219		250
220	=head4 db_txn_finish (DB_TXN txn, U32 flags = 0, SV callback = &PL_sv_undef)	251	=head3 db_txn_finish (DB_TXN txn, U32 flags = 0, SV callback = &PL_sv_undef)
221		252
222	This is not actually a Berkeley DB function but a BDB module	253	This is not actually a Berkeley DB function but a BDB module
223	extension. The background for this exytension is: It is very annoying to	254	extension. The background for this exytension is: It is very annoying to
224	have to check every single BDB function for error returns and provide a	255	have to check every single BDB function for error returns and provide a
225	codepath out of your transaction. While the BDB module still makes this	256	codepath out of your transaction. While the BDB module still makes this
…		…
251		282
252	You can use the C<< $txn->failed >> method to check wether a transaction	283	You can use the C<< $txn->failed >> method to check wether a transaction
253	has failed in this way and abort further processing (excluding	284	has failed in this way and abort further processing (excluding
254	C<db_txn_finish>).	285	C<db_txn_finish>).
255		286
256	=head3 DB_ENV/database environment methods	287	=head2 DB_ENV/database environment methods
257		288
258	Methods available on DB_ENV/$env handles:	289	Methods available on DB_ENV/$env handles:
259		290
260	DESTROY (DB_ENV_ornull *env)	291	DESTROY (DB_ENV_ornull *env)
261	CODE:	292	CODE:
…		…
265	$int = $env->set_data_dir (const char *dir)	296	$int = $env->set_data_dir (const char *dir)
266	$int = $env->set_tmp_dir (const char *dir)	297	$int = $env->set_tmp_dir (const char *dir)
267	$int = $env->set_lg_dir (const char *dir)	298	$int = $env->set_lg_dir (const char *dir)
268	$int = $env->set_shm_key (long shm_key)	299	$int = $env->set_shm_key (long shm_key)
269	$int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0)	300	$int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0)
270	$int = $env->set_flags (U32 flags, int onoff)	301	$int = $env->set_flags (U32 flags, int onoff = 1)
		302	$int = $env->log_set_config (U32 flags, int onoff = 1) (v4.7)
		303	$int = $env->set_intermediate_dir_mode (const char *modestring) (v4.7)
271	$env->set_errfile (FILE *errfile = 0)	304	$env->set_errfile (FILE *errfile = 0)
272	$env->set_msgfile (FILE *msgfile = 0)	305	$env->set_msgfile (FILE *msgfile = 0)
273	$int = $env->set_verbose (U32 which, int onoff = 1)	306	$int = $env->set_verbose (U32 which, int onoff = 1)
274	$int = $env->set_encrypt (const char *password, U32 flags = 0)	307	$int = $env->set_encrypt (const char *password, U32 flags = 0)
275	$int = $env->set_timeout (NV timeout_seconds, U32 flags = SET_TXN_TIMEOUT)	308	$int = $env->set_timeout (NV timeout_seconds, U32 flags = SET_TXN_TIMEOUT)
…		…
287	$int = $env->mutex_set_max (U32 max)	320	$int = $env->mutex_set_max (U32 max)
288	$int = $env->mutex_set_align (U32 align)	321	$int = $env->mutex_set_align (U32 align)
289		322
290	$txn = $env->txn_begin (DB_TXN_ornull *parent = 0, U32 flags = 0)	323	$txn = $env->txn_begin (DB_TXN_ornull *parent = 0, U32 flags = 0)
291	flags: READ_COMMITTED READ_UNCOMMITTED TXN_NOSYNC TXN_NOWAIT TXN_SNAPSHOT TXN_SYNC TXN_WAIT TXN_WRITE_NOSYNC	324	flags: READ_COMMITTED READ_UNCOMMITTED TXN_NOSYNC TXN_NOWAIT TXN_SNAPSHOT TXN_SYNC TXN_WAIT TXN_WRITE_NOSYNC
		325	$txn = $env->cdsgroup_begin; (v4.5)
292		326
293	=head4 Example:	327	=head3 Example:
294		328
295	use AnyEvent;	329	use AnyEvent;
296	use BDB;	330	use BDB;
297		331
298	our $FH; open $FH, "<&=" . BDB::poll_fileno;	332	our $FH; open $FH, "<&=" . BDB::poll_fileno;
…		…
310	0600;	344	0600;
311		345
312	$env->set_flags (BDB::AUTO_COMMIT \| BDB::TXN_NOSYNC, 1);	346	$env->set_flags (BDB::AUTO_COMMIT \| BDB::TXN_NOSYNC, 1);
313		347
314		348
315	=head3 DB/database methods	349	=head2 DB/database methods
316		350
317	Methods available on DB/$db handles:	351	Methods available on DB/$db handles:
318		352
319	DESTROY (DB_ornull *db)	353	DESTROY (DB_ornull *db)
320	CODE:	354	CODE:
…		…
346		380
347	$dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0)	381	$dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0)
348	flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT	382	flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT
349	$seq = $db->sequence (U32 flags = 0)	383	$seq = $db->sequence (U32 flags = 0)
350		384
351	=head4 Example:	385	=head3 Example:
352		386
353	my $db = db_create $env;	387	my $db = db_create $env;
354	db_open $db, undef, "table", undef, BDB::BTREE, BDB::AUTO_COMMIT \| BDB::CREATE \| BDB::READ_UNCOMMITTED, 0600;	388	db_open $db, undef, "table", undef, BDB::BTREE, BDB::AUTO_COMMIT \| BDB::CREATE \| BDB::READ_UNCOMMITTED, 0600;
355		389
356	for (1..1000) {	390	for (1..1000) {
…		…
363	db_del $db, undef, "key $_" for 1..1000;	397	db_del $db, undef, "key $_" for 1..1000;
364		398
365	db_sync $db;	399	db_sync $db;
366		400
367		401
368	=head3 DB_TXN/transaction methods	402	=head2 DB_TXN/transaction methods
369		403
370	Methods available on DB_TXN/$txn handles:	404	Methods available on DB_TXN/$txn handles:
371		405
372	DESTROY (DB_TXN_ornull *txn)	406	DESTROY (DB_TXN_ornull *txn)
373	CODE:	407	CODE:
…		…
379		413
380	$bool = $txn->failed	414	$bool = $txn->failed
381	# see db_txn_finish documentation, above	415	# see db_txn_finish documentation, above
382		416
383		417
384	=head3 DBC/cursor methods	418	=head2 DBC/cursor methods
385		419
386	Methods available on DBC/$dbc handles:	420	Methods available on DBC/$dbc handles:
387		421
388	DESTROY (DBC_ornull *dbc)	422	DESTROY (DBC_ornull *dbc)
389	CODE:	423	CODE:
390	if (dbc)	424	if (dbc)
391	dbc->c_close (dbc);	425	dbc->c_close (dbc);
392		426
		427	$int = $cursor->set_priority ($priority = PRIORITY_*) (v4.6)
		428
393	=head4 Example:	429	=head3 Example:
394		430
395	my $c = $db->cursor;	431	my $c = $db->cursor;
396		432
397	for (;;) {	433	for (;;) {
398	db_c_get $c, my $key, my $data, BDB::NEXT;	434	db_c_get $c, my $key, my $data, BDB::NEXT;
…		…
401	}	437	}
402		438
403	db_c_close $c;	439	db_c_close $c;
404		440
405		441
406	=head3 DB_SEQUENCE/sequence methods	442	=head2 DB_SEQUENCE/sequence methods
407		443
408	Methods available on DB_SEQUENCE/$seq handles:	444	Methods available on DB_SEQUENCE/$seq handles:
409		445
410	DESTROY (DB_SEQUENCE_ornull *seq)	446	DESTROY (DB_SEQUENCE_ornull *seq)
411	CODE:	447	CODE:
…		…
416	$int = $seq->set_cachesize (U32 size)	452	$int = $seq->set_cachesize (U32 size)
417	$int = $seq->set_flags (U32 flags)	453	$int = $seq->set_flags (U32 flags)
418	flags: SEQ_DEC SEQ_INC SEQ_WRAP	454	flags: SEQ_DEC SEQ_INC SEQ_WRAP
419	$int = $seq->set_range (db_seq_t min, db_seq_t max)	455	$int = $seq->set_range (db_seq_t min, db_seq_t max)
420		456
421	=head4 Example:	457	=head3 Example:
422		458
423	my $seq = $db->sequence;	459	my $seq = $db->sequence;
424		460
425	db_sequence_open $seq, undef, "seq", BDB::CREATE;	461	db_sequence_open $seq, undef, "seq", BDB::CREATE;
426	db_sequence_get $seq, undef, 1, my $value;	462	db_sequence_get $seq, undef, 1, my $value;
427		463
428		464
429	=head2 SUPPORT FUNCTIONS	465	=head1 SUPPORT FUNCTIONS
430		466
431	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	467	=head2 EVENT PROCESSING AND EVENT LOOP INTEGRATION
432		468
433	=over 4	469	=over 4
434		470
435	=item $msg = BDB::strerror [$errno]	471	=item $msg = BDB::strerror [$errno]
436		472
437	Returns the string corresponding to the given errno value. If no argument	473	Returns the string corresponding to the given errno value. If no argument
438	is given, use C<$!>.	474	is given, use C<$!>.
		475
		476	Note that the BDB module also patches the C<$!> variable directly, so you
		477	should be able to get a bdb error string by simply stringifying C<$!>.
439		478
440	=item $fileno = BDB::poll_fileno	479	=item $fileno = BDB::poll_fileno
441		480
442	Return the I<request result pipe file descriptor>. This filehandle must be	481	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	482	polled for reading by some mechanism outside this module (e.g. Event or
…		…
520	BDB::poll_wait, BDB::poll_cb	559	BDB::poll_wait, BDB::poll_cb
521	while BDB::nreqs;	560	while BDB::nreqs;
522		561
523	=back	562	=back
524		563
		564	=head2 VERSION CHECKING
		565
		566	BerkeleyDB comes in various versions, many of them have minor
		567	incompatibilities. This means that traditional "at least version x.x"
		568	checks are often not sufficient.
		569
		570	Example: set the log_autoremove option in a way compatible with <v4.7 and
		571	v4.7. Note the use of & on the constants to avoid triggering a compiletime
		572	bug when the symbol isn't available.
		573
		574	$DB_ENV->set_flags (&BDB::LOG_AUTOREMOVE ) if BDB::VERSION v0, v4.7;
		575	$DB_ENV->log_set_config (&BDB::LOG_AUTO_REMOVE) if BDB::VERSION v4.7;
		576
		577	=over 4
		578
		579	=item BDB::VERSION
		580
		581	The C<BDB::VERSION> function, when called without arguments, returns the
		582	Berkeley DB version as a v-string (usually with 3 components). You should
		583	use C<lt> and C<ge> operators exclusively to make comparisons.
		584
		585	Example: check for at least version 4.7.
		586
		587	BDB::VERSION ge v4.7 or die;
		588
		589	=item BDB::VERSION min-version
		590
		591	Returns true if the BDB version is at least the given version (specified
		592	as a v-string), false otherwise.
		593
		594	Example: check for at least version 4.5.
		595
		596	BDB::VERSION v4.7 or die;
		597
		598	=item BDB::VERSION min-version, max-version
		599
		600	Returns true of the BDB version is at least version C<min-version> (specify C<undef> or C<v0> for any minimum version)
		601	and less then C<max-version>.
		602
		603	Example: check wether version is strictly less then v4.7.
		604
		605	BDB::VERSION v0, v4.7
		606	or die "version 4.7 is not yet supported";
		607
		608	=back
		609
		610	=cut
		611
		612	sub VERSION {
		613	# I was dumb enough to override the VERSION method here, so let's try
		614	# to fix it up.
		615
		616	if ($_[0] eq __PACKAGE__) {
		617	$VERSION
		618	} else {
		619	if (@_ > 0) {
		620	return undef if VERSION_v lt $_[0];
		621	if (@_ > 1) {
		622	return undef if VERSION_v ge $_[1];
		623	}
		624	}
		625
		626	VERSION_v
		627	}
		628	}
		629
525	=head3 CONTROLLING THE NUMBER OF THREADS	630	=head2 CONTROLLING THE NUMBER OF THREADS
526		631
527	=over 4	632	=over 4
528		633
529	=item BDB::min_parallel $nthreads	634	=item BDB::min_parallel $nthreads
530		635
…		…
591		696
592	You can still queue as many requests as you want. Therefore,	697	You can still queue as many requests as you want. Therefore,
593	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	698	C<max_oustsanding> is mainly useful in simple scripts (with low values) or
594	as a stop gap to shield against fatal memory overflow (with large values).	699	as a stop gap to shield against fatal memory overflow (with large values).
595		700
596	=item BDB::set_sync_prepare $cb	701	=item $old_cb = BDB::set_sync_prepare $cb
597		702
598	Sets a callback that is called whenever a request is created without an	703	Sets a callback that is called whenever a request is created without an
599	explicit callback. It has to return two code references. The first is used	704	explicit callback. It has to return two code references. The first is used
600	as the request callback, and the second is called to wait until the first	705	as the request callback (it should save the return status), and the second
601	callback has been called. The default implementation works like this:	706	is called to wait until the first callback has been called (it must set
		707	C<$!> to the return status).
		708
		709	This mechanism can be used to include BDB into other event mechanisms,
		710	such as L<Coro::BDB>.
		711
		712	To allow other, callback-based, events to be executed while callback-less
		713	ones are run, you could use this sync prepare function:
602		714
603	sub {	715	sub {
604	my $status;	716	my $status;
605	(	717	(
606	sub { $status = $! },	718	sub { $status = $! },
607	sub { BDB::poll while !defined $status; $! = $status },	719	sub { BDB::poll while !defined $status; $! = $status },
608	)	720	)
609	}	721	}
610		722
		723	It works by polling for results till the request has finished and then
		724	sets C<$!> to the return value. This means that if you don't use a
		725	callback, BDB would simply fall back to synchronous operations.
		726
		727	By default, or if the sync prepare function is set to C<undef>, is to
		728	execute callback-less BDB requests in the foreground thread, setting C<$!>
		729	to the return value, without polling for other events.
		730
611	=back	731	=back
612		732
613	=head3 STATISTICAL INFORMATION	733	=head2 STATISTICAL INFORMATION
614		734
615	=over 4	735	=over 4
616		736
617	=item BDB::nreqs	737	=item BDB::nreqs
618		738
…		…
636		756
637	=back	757	=back
638		758
639	=cut	759	=cut
640		760
641	set_sync_prepare {	761	set_sync_prepare (undef);
642	my $status;
643	(
644	sub {
645	$status = $!;
646	},
647	sub {
648	BDB::poll while !defined $status;
649	$! = $status;
650	},
651	)
652	};
653		762
654	min_parallel 8;	763	min_parallel 8;
655		764
656	END { flush }	765	END { flush }
657		766
658	1;	767	1;
659		768
		769	=head1 COMMON PITFALLS
		770
		771	=head2 Unexpected Crashes
		772
		773	Remember that, by default, BDB will execute requests in parallel, in
		774	somewhat random order. That means that it is easy to run a C<db_get>
		775	request on thesa me database as a concurrent C<db_close> request, leading
		776	to a crash, silent data corruption, eventually the next world war on
		777	terrorism.
		778
		779	If you only ever use foreground requests (without a callback), this will
		780	not be an issue.
		781
		782	=head2 Unexpected Freezes or Deadlocks
		783
		784	Remember that, by default, BDB will execute requests in parallel, which
		785	easily leads to deadlocks (even concurrent put's on the same database can
		786	deadlock).
		787
		788	You either need to run deadlock detection (and handle the resulting
		789	errors), or make sure only one process ever updates the database, ine one
		790	thread, e.g. by using only foreground requests (without a callback).
		791
660	=head2 FORK BEHAVIOUR	792	=head1 FORK BEHAVIOUR
661		793
662	This module should do "the right thing" when the process using it forks:	794	This module should do "the right thing" when the process using it forks:
663		795
664	Before the fork, BDB enters a quiescent state where no requests	796	Before the fork, BDB enters a quiescent state where no requests
665	can be added in other threads and no results will be processed. After	797	can be added in other threads and no results will be processed. After
…		…
671		803
672	In short: the parent will, after a short pause, continue as if fork had	804	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	805	not been called, while the child will act as if BDB has not been used
674	yet.	806	yet.
675		807
		808	Win32 note: there is no fork on win32, and perls emulation of it is too
		809	broken to be supported, so do not use BDB in a windows pseudo-fork, better
		810	yet, switch to a more capable platform.
		811
676	=head2 MEMORY USAGE	812	=head1 MEMORY USAGE
677		813
678	Per-request usage:	814	Per-request usage:
679		815
680	Each aio request uses - depending on your architecture - around 100-200	816	Each aio request uses - depending on your architecture - around 100-200
681	bytes of memory. In addition, stat requests need a stat buffer (possibly	817	bytes of memory. In addition, stat requests need a stat buffer (possibly
…		…
690		826
691	In the execution phase, some aio requests require more memory for	827	In the execution phase, some aio requests require more memory for
692	temporary buffers, and each thread requires a stack and other data	828	temporary buffers, and each thread requires a stack and other data
693	structures (usually around 16k-128k, depending on the OS).	829	structures (usually around 16k-128k, depending on the OS).
694		830
		831	=head1 WIN32 FILENAMES/DATABASE NAME MESS
		832
		833	Perl on Win32 supports only ASCII filenames (the reason is that it abuses
		834	an internal flag to store wether a filename is Unicode or ANSI, but that
		835	flag is used for somethign else in the perl core, so there is no way to
		836	detect wether a filename is ANSI or Unicode-encoded). The BDB module
		837	tries to work around this issue by assuming that the filename is an ANSI
		838	filename and BDB was built for unicode support.
		839
695	=head1 KNOWN BUGS	840	=head1 KNOWN BUGS
696		841
697	Known bugs will be fixed in the next release, except:	842	Known bugs will be fixed in the next release, except:
698		843
699	If you use a transaction in any request, and the request returns	844	If you use a transaction in any request, and the request returns
…		…
701	TXN_DEADLOCK flag will be set on the transaction. See C<db_txn_finish>,	846	TXN_DEADLOCK flag will be set on the transaction. See C<db_txn_finish>,
702	above.	847	above.
703		848
704	=head1 SEE ALSO	849	=head1 SEE ALSO
705		850
706	L<Coro::BDB>, L<IO::AIO>.	851	L<AnyEvent::BDB> (event loop integration), L<Coro::BDB> (more natural
		852	syntax), L<IO::AIO> (nice to have).
707		853
708	=head1 AUTHOR	854	=head1 AUTHOR
709		855
710	Marc Lehmann <schmorp@schmorp.de>	856	Marc Lehmann <schmorp@schmorp.de>
711	http://home.schmorp.de/	857	http://home.schmorp.de/

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Comparing BDB/BDB.pm (file contents): Revision 1.25 by root, Mon Dec 10 21:19:06 2007 UTC vs. Revision 1.53 by root, Tue Oct 21 02:21:25 2008 UTC

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Comparing BDB/BDB.pm (file contents):
Revision 1.25 by root, Mon Dec 10 21:19:06 2007 UTC vs.
Revision 1.53 by root, Tue Oct 21 02:21:25 2008 UTC