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

Comparing BDB/BDB.pm (file contents):
Revision 1.24 by root, Mon Dec 10 04:57:14 2007 UTC vs.
Revision 1.55 by root, Sun Jan 4 10:48:15 2009 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 = '1.82';
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
117	db_open db_close db_compact db_sync db_put db_get db_pget db_del db_key_range	121	db_env_log_archive
		122	db_open db_close db_compact db_sync db_upgrade
		123	db_put db_exists db_get db_pget db_del db_key_range
118	db_txn_commit db_txn_abort db_txn_finish	124	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	125	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	126	db_sequence_open db_sequence_close
121	db_sequence_get db_sequence_remove	127	db_sequence_get db_sequence_remove
122	);	128	);
…		…
130		136
131	require XSLoader;	137	require XSLoader;
132	XSLoader::load ("BDB", $VERSION);	138	XSLoader::load ("BDB", $VERSION);
133	}	139	}
134		140
135	=head2 BERKELEYDB FUNCTIONS	141	=head1 BERKELEYDB FUNCTIONS
136		142
137	All of these are functions. The create functions simply return a new	143	All of these are functions. The create functions simply return a new
138	object and never block. All the remaining functions all take an optional	144	object and never block. All the remaining functions take an optional
139	callback as last argument. If it is missing, then the function will be	145	callback as last argument. If it is missing, then the function will be
140	executed synchronously. In both cases, C<$!> will reflect the return value	146	executed synchronously. In both cases, C<$!> will reflect the return value
141	of the function.	147	of the function.
142		148
143	BDB functions that cannot block (mostly functions that manipulate	149	BDB functions that cannot block (mostly functions that manipulate
144	settings) are method calls on the relevant objects, so the rule of thumb	150	settings) are method calls on the relevant objects, so the rule of thumb
145	is: if its a method, its not blocking, if its a function, it takes a	151	is: if it's a method, it's not blocking, if it's a function, it takes a
146	callback as last argument.	152	callback as last argument.
147		153
148	In the following, C<$int> signifies an integer return value,	154	In the following, C<$int> signifies an integer return value,
149	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),
150	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
151	integer, C<NV> is a floating point value.	157	floating point value.
152		158
153	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
154	values), and the C<SV *callback> is the optional callback function to call	160	values).
155	when the request is completed.
156		161
157	The various C<DB_ENV> etc. arguments are handles return by	162	The various C<DB_ENV> etc. arguments are handles return by
158	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
159	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>
160	for them, resulting a NULL pointer on the C level.	165	for them, resulting a NULL pointer on the C level.
161		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
162	=head3 BDB functions	190	=head2 BDB functions
163		191
164	Functions in the BDB namespace, exported by default:	192	Functions in the BDB namespace, exported by default:
165		193
166	$env = db_env_create (U32 env_flags = 0)	194	$env = db_env_create (U32 env_flags = 0)
167	flags: RPCCLIENT	195	flags: RPCCLIENT
168		196
169	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)
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	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
171	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)
172	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)
173	flags: FORCE	201	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)	202	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	203	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)	204	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)	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)
178		209
179	$db = db_create (DB_ENV *env = 0, U32 flags = 0)	210	$db = db_create (DB_ENV *env = 0, U32 flags = 0)
180	flags: XA_CREATE	211	flags: XA_CREATE
181		212
182	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)
183	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
184	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)
185	flags: DB_NOSYNC	216	flags: DB_NOSYNC
		217	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)	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)
187	flags: FREELIST_ONLY FREE_SPACE	219	flags: FREELIST_ONLY FREE_SPACE
188	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)
189	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)
190	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)
191	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)
192	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)
193	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
194	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)
195	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
196	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)
…		…
213	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)
214	flags: TXN_NOSYNC	247	flags: TXN_NOSYNC
215	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)
216	flags: TXN_NOSYNC	249	flags: TXN_NOSYNC
217		250
218	=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)
219		252
220	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
221	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
222	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
223	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
…		…
249		282
250	You can use the C<< $txn->failed >> method to check wether a transaction	283	You can use the C<< $txn->failed >> method to check wether a transaction
251	has failed in this way and abort further processing (excluding	284	has failed in this way and abort further processing (excluding
252	C<db_txn_finish>).	285	C<db_txn_finish>).
253		286
		287
254	=head3 DB_ENV/database environment methods	288	=head2 DB_ENV/database environment methods
255		289
256	Methods available on DB_ENV/$env handles:	290	Methods available on DB_ENV/$env handles:
257		291
258	DESTROY (DB_ENV_ornull *env)	292	DESTROY (DB_ENV_ornull *env)
259	CODE:	293	CODE:
…		…
263	$int = $env->set_data_dir (const char *dir)	297	$int = $env->set_data_dir (const char *dir)
264	$int = $env->set_tmp_dir (const char *dir)	298	$int = $env->set_tmp_dir (const char *dir)
265	$int = $env->set_lg_dir (const char *dir)	299	$int = $env->set_lg_dir (const char *dir)
266	$int = $env->set_shm_key (long shm_key)	300	$int = $env->set_shm_key (long shm_key)
267	$int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0)	301	$int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0)
268	$int = $env->set_flags (U32 flags, int onoff)	302	$int = $env->set_flags (U32 flags, int onoff = 1)
		303	$int = $env->log_set_config (U32 flags, int onoff = 1) (v4.7)
		304	$int = $env->set_intermediate_dir_mode (const char *modestring) (v4.7)
269	$env->set_errfile (FILE *errfile = 0)	305	$env->set_errfile (FILE *errfile = 0)
270	$env->set_msgfile (FILE *msgfile = 0)	306	$env->set_msgfile (FILE *msgfile = 0)
271	$int = $env->set_verbose (U32 which, int onoff = 1)	307	$int = $env->set_verbose (U32 which, int onoff = 1)
272	$int = $env->set_encrypt (const char *password, U32 flags = 0)	308	$int = $env->set_encrypt (const char *password, U32 flags = 0)
273	$int = $env->set_timeout (NV timeout_seconds, U32 flags = SET_TXN_TIMEOUT)	309	$int = $env->set_timeout (NV timeout_seconds, U32 flags = SET_TXN_TIMEOUT)
…		…
285	$int = $env->mutex_set_max (U32 max)	321	$int = $env->mutex_set_max (U32 max)
286	$int = $env->mutex_set_align (U32 align)	322	$int = $env->mutex_set_align (U32 align)
287		323
288	$txn = $env->txn_begin (DB_TXN_ornull *parent = 0, U32 flags = 0)	324	$txn = $env->txn_begin (DB_TXN_ornull *parent = 0, U32 flags = 0)
289	flags: READ_COMMITTED READ_UNCOMMITTED TXN_NOSYNC TXN_NOWAIT TXN_SNAPSHOT TXN_SYNC TXN_WAIT TXN_WRITE_NOSYNC	325	flags: READ_COMMITTED READ_UNCOMMITTED TXN_NOSYNC TXN_NOWAIT TXN_SNAPSHOT TXN_SYNC TXN_WAIT TXN_WRITE_NOSYNC
		326	$txn = $env->cdsgroup_begin; (v4.5)
290		327
291	=head4 Example:	328	=head3 Example:
292		329
293	use AnyEvent;	330	use AnyEvent;
294	use BDB;	331	use BDB;
295		332
296	our $FH; open $FH, "<&=" . BDB::poll_fileno;	333	our $FH; open $FH, "<&=" . BDB::poll_fileno;
…		…
308	0600;	345	0600;
309		346
310	$env->set_flags (BDB::AUTO_COMMIT \| BDB::TXN_NOSYNC, 1);	347	$env->set_flags (BDB::AUTO_COMMIT \| BDB::TXN_NOSYNC, 1);
311		348
312		349
313	=head3 DB/database methods	350	=head2 DB/database methods
314		351
315	Methods available on DB/$db handles:	352	Methods available on DB/$db handles:
316		353
317	DESTROY (DB_ornull *db)	354	DESTROY (DB_ornull *db)
318	CODE:	355	CODE:
…		…
344		381
345	$dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0)	382	$dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0)
346	flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT	383	flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT
347	$seq = $db->sequence (U32 flags = 0)	384	$seq = $db->sequence (U32 flags = 0)
348		385
349	=head4 Example:	386	=head3 Example:
350		387
351	my $db = db_create $env;	388	my $db = db_create $env;
352	db_open $db, undef, "table", undef, BDB::BTREE, BDB::AUTO_COMMIT \| BDB::CREATE \| BDB::READ_UNCOMMITTED, 0600;	389	db_open $db, undef, "table", undef, BDB::BTREE, BDB::AUTO_COMMIT \| BDB::CREATE \| BDB::READ_UNCOMMITTED, 0600;
353		390
354	for (1..1000) {	391	for (1..1000) {
…		…
361	db_del $db, undef, "key $_" for 1..1000;	398	db_del $db, undef, "key $_" for 1..1000;
362		399
363	db_sync $db;	400	db_sync $db;
364		401
365		402
366	=head3 DB_TXN/transaction methods	403	=head2 DB_TXN/transaction methods
367		404
368	Methods available on DB_TXN/$txn handles:	405	Methods available on DB_TXN/$txn handles:
369		406
370	DESTROY (DB_TXN_ornull *txn)	407	DESTROY (DB_TXN_ornull *txn)
371	CODE:	408	CODE:
…		…
377		414
378	$bool = $txn->failed	415	$bool = $txn->failed
379	# see db_txn_finish documentation, above	416	# see db_txn_finish documentation, above
380		417
381		418
382	=head3 DBC/cursor methods	419	=head2 DBC/cursor methods
383		420
384	Methods available on DBC/$dbc handles:	421	Methods available on DBC/$dbc handles:
385		422
386	DESTROY (DBC_ornull *dbc)	423	DESTROY (DBC_ornull *dbc)
387	CODE:	424	CODE:
388	if (dbc)	425	if (dbc)
389	dbc->c_close (dbc);	426	dbc->c_close (dbc);
390		427
		428	$int = $cursor->set_priority ($priority = PRIORITY_*) (v4.6)
		429
391	=head4 Example:	430	=head3 Example:
392		431
393	my $c = $db->cursor;	432	my $c = $db->cursor;
394		433
395	for (;;) {	434	for (;;) {
396	db_c_get $c, my $key, my $data, BDB::NEXT;	435	db_c_get $c, my $key, my $data, BDB::NEXT;
…		…
399	}	438	}
400		439
401	db_c_close $c;	440	db_c_close $c;
402		441
403		442
404	=head3 DB_SEQUENCE/sequence methods	443	=head2 DB_SEQUENCE/sequence methods
405		444
406	Methods available on DB_SEQUENCE/$seq handles:	445	Methods available on DB_SEQUENCE/$seq handles:
407		446
408	DESTROY (DB_SEQUENCE_ornull *seq)	447	DESTROY (DB_SEQUENCE_ornull *seq)
409	CODE:	448	CODE:
…		…
414	$int = $seq->set_cachesize (U32 size)	453	$int = $seq->set_cachesize (U32 size)
415	$int = $seq->set_flags (U32 flags)	454	$int = $seq->set_flags (U32 flags)
416	flags: SEQ_DEC SEQ_INC SEQ_WRAP	455	flags: SEQ_DEC SEQ_INC SEQ_WRAP
417	$int = $seq->set_range (db_seq_t min, db_seq_t max)	456	$int = $seq->set_range (db_seq_t min, db_seq_t max)
418		457
419	=head4 Example:	458	=head3 Example:
420		459
421	my $seq = $db->sequence;	460	my $seq = $db->sequence;
422		461
423	db_sequence_open $seq, undef, "seq", BDB::CREATE;	462	db_sequence_open $seq, undef, "seq", BDB::CREATE;
424	db_sequence_get $seq, undef, 1, my $value;	463	db_sequence_get $seq, undef, 1, my $value;
425		464
426		465
427	=head2 SUPPORT FUNCTIONS	466	=head1 SUPPORT FUNCTIONS
428		467
429	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	468	=head2 EVENT PROCESSING AND EVENT LOOP INTEGRATION
430		469
431	=over 4	470	=over 4
432		471
433	=item $msg = BDB::strerror [$errno]	472	=item $msg = BDB::strerror [$errno]
434		473
435	Returns the string corresponding to the given errno value. If no argument	474	Returns the string corresponding to the given errno value. If no argument
436	is given, use C<$!>.	475	is given, use C<$!>.
		476
		477	Note that the BDB module also patches the C<$!> variable directly, so you
		478	should be able to get a bdb error string by simply stringifying C<$!>.
437		479
438	=item $fileno = BDB::poll_fileno	480	=item $fileno = BDB::poll_fileno
439		481
440	Return the I<request result pipe file descriptor>. This filehandle must be	482	Return the I<request result pipe file descriptor>. This filehandle must be
441	polled for reading by some mechanism outside this module (e.g. Event or	483	polled for reading by some mechanism outside this module (e.g. Event or
…		…
518	BDB::poll_wait, BDB::poll_cb	560	BDB::poll_wait, BDB::poll_cb
519	while BDB::nreqs;	561	while BDB::nreqs;
520		562
521	=back	563	=back
522		564
		565	=head2 VERSION CHECKING
		566
		567	BerkeleyDB comes in various versions, many of them have minor
		568	incompatibilities. This means that traditional "at least version x.x"
		569	checks are often not sufficient.
		570
		571	Example: set the log_autoremove option in a way compatible with <v4.7 and
		572	v4.7. Note the use of & on the constants to avoid triggering a compiletime
		573	bug when the symbol isn't available.
		574
		575	$DB_ENV->set_flags (&BDB::LOG_AUTOREMOVE ) if BDB::VERSION v0, v4.7;
		576	$DB_ENV->log_set_config (&BDB::LOG_AUTO_REMOVE) if BDB::VERSION v4.7;
		577
		578	=over 4
		579
		580	=item BDB::VERSION
		581
		582	The C<BDB::VERSION> function, when called without arguments, returns the
		583	Berkeley DB version as a v-string (usually with 3 components). You should
		584	use C<lt> and C<ge> operators exclusively to make comparisons.
		585
		586	Example: check for at least version 4.7.
		587
		588	BDB::VERSION ge v4.7 or die;
		589
		590	=item BDB::VERSION min-version
		591
		592	Returns true if the BDB version is at least the given version (specified
		593	as a v-string), false otherwise.
		594
		595	Example: check for at least version 4.5.
		596
		597	BDB::VERSION v4.7 or die;
		598
		599	=item BDB::VERSION min-version, max-version
		600
		601	Returns true of the BDB version is at least version C<min-version> (specify C<undef> or C<v0> for any minimum version)
		602	and less then C<max-version>.
		603
		604	Example: check wether version is strictly less then v4.7.
		605
		606	BDB::VERSION v0, v4.7
		607	or die "version 4.7 is not yet supported";
		608
		609	=back
		610
		611	=cut
		612
		613	sub VERSION {
		614	# I was dumb enough to override the VERSION method here, so let's try
		615	# to fix it up.
		616
		617	if ($_[0] eq __PACKAGE__) {
		618	$VERSION
		619	} else {
		620	if (@_ > 0) {
		621	return undef if VERSION_v lt $_[0];
		622	if (@_ > 1) {
		623	return undef if VERSION_v ge $_[1];
		624	}
		625	}
		626
		627	VERSION_v
		628	}
		629	}
		630
523	=head3 CONTROLLING THE NUMBER OF THREADS	631	=head2 CONTROLLING THE NUMBER OF THREADS
524		632
525	=over 4	633	=over 4
526		634
527	=item BDB::min_parallel $nthreads	635	=item BDB::min_parallel $nthreads
528		636
…		…
589		697
590	You can still queue as many requests as you want. Therefore,	698	You can still queue as many requests as you want. Therefore,
591	C<max_oustsanding> is mainly useful in simple scripts (with low values) or	699	C<max_oustsanding> is mainly useful in simple scripts (with low values) or
592	as a stop gap to shield against fatal memory overflow (with large values).	700	as a stop gap to shield against fatal memory overflow (with large values).
593		701
594	=item BDB::set_sync_prepare $cb	702	=item $old_cb = BDB::set_sync_prepare $cb
595		703
596	Sets a callback that is called whenever a request is created without an	704	Sets a callback that is called whenever a request is created without an
597	explicit callback. It has to return two code references. The first is used	705	explicit callback. It has to return two code references. The first is used
598	as the request callback, and the second is called to wait until the first	706	as the request callback (it should save the return status), and the second
599	callback has been called. The default implementation works like this:	707	is called to wait until the first callback has been called (it must set
		708	C<$!> to the return status).
		709
		710	This mechanism can be used to include BDB into other event mechanisms,
		711	such as L<Coro::BDB>.
		712
		713	To allow other, callback-based, events to be executed while callback-less
		714	ones are run, you could use this sync prepare function:
600		715
601	sub {	716	sub {
602	my $status;	717	my $status;
603	(	718	(
604	sub { $status = $! },	719	sub { $status = $! },
605	sub { BDB::poll while !defined $status; $! = $status },	720	sub { BDB::poll while !defined $status; $! = $status },
606	)	721	)
607	}	722	}
608		723
		724	It works by polling for results till the request has finished and then
		725	sets C<$!> to the return value. This means that if you don't use a
		726	callback, BDB would simply fall back to synchronous operations.
		727
		728	By default, or if the sync prepare function is set to C<undef>, is to
		729	execute callback-less BDB requests in the foreground thread, setting C<$!>
		730	to the return value, without polling for other events.
		731
609	=back	732	=back
610		733
611	=head3 STATISTICAL INFORMATION	734	=head2 STATISTICAL INFORMATION
612		735
613	=over 4	736	=over 4
614		737
615	=item BDB::nreqs	738	=item BDB::nreqs
616		739
…		…
634		757
635	=back	758	=back
636		759
637	=cut	760	=cut
638		761
639	set_sync_prepare {	762	set_sync_prepare (undef);
640	my $status;
641	(
642	sub {
643	$status = $!;
644	},
645	sub {
646	BDB::poll while !defined $status;
647	$! = $status;
648	},
649	)
650	};
651		763
652	min_parallel 8;	764	min_parallel 8;
653		765
654	END { flush }	766	END { flush }
655		767
656	1;	768	1;
657		769
		770	=head1 COMMON PITFALLS
		771
		772	=head2 Unexpected Crashes
		773
		774	Remember that, by default, BDB will execute requests in parallel, in
		775	somewhat random order. That means that it is easy to run a C<db_get>
		776	request on thesa me database as a concurrent C<db_close> request, leading
		777	to a crash, silent data corruption, eventually the next world war on
		778	terrorism.
		779
		780	If you only ever use foreground requests (without a callback), this will
		781	not be an issue.
		782
		783	=head2 Unexpected Freezes or Deadlocks
		784
		785	Remember that, by default, BDB will execute requests in parallel, which
		786	easily leads to deadlocks (even concurrent put's on the same database can
		787	deadlock).
		788
		789	You either need to run deadlock detection (and handle the resulting
		790	errors), or make sure only one process ever updates the database, ine one
		791	thread, e.g. by using only foreground requests (without a callback).
		792
658	=head2 FORK BEHAVIOUR	793	=head1 FORK BEHAVIOUR
659		794
660	This module should do "the right thing" when the process using it forks:	795	This module should do "the right thing" when the process using it forks:
661		796
662	Before the fork, BDB enters a quiescent state where no requests	797	Before the fork, BDB enters a quiescent state where no requests
663	can be added in other threads and no results will be processed. After	798	can be added in other threads and no results will be processed. After
…		…
669		804
670	In short: the parent will, after a short pause, continue as if fork had	805	In short: the parent will, after a short pause, continue as if fork had
671	not been called, while the child will act as if BDB has not been used	806	not been called, while the child will act as if BDB has not been used
672	yet.	807	yet.
673		808
		809	Win32 note: there is no fork on win32, and perls emulation of it is too
		810	broken to be supported, so do not use BDB in a windows pseudo-fork, better
		811	yet, switch to a more capable platform.
		812
674	=head2 MEMORY USAGE	813	=head1 MEMORY USAGE
675		814
676	Per-request usage:	815	Per-request usage:
677		816
678	Each aio request uses - depending on your architecture - around 100-200	817	Each aio request uses - depending on your architecture - around 100-200
679	bytes of memory. In addition, stat requests need a stat buffer (possibly	818	bytes of memory. In addition, stat requests need a stat buffer (possibly
…		…
688		827
689	In the execution phase, some aio requests require more memory for	828	In the execution phase, some aio requests require more memory for
690	temporary buffers, and each thread requires a stack and other data	829	temporary buffers, and each thread requires a stack and other data
691	structures (usually around 16k-128k, depending on the OS).	830	structures (usually around 16k-128k, depending on the OS).
692		831
		832	=head1 WIN32 FILENAMES/DATABASE NAME MESS
		833
		834	Perl on Win32 supports only ASCII filenames (the reason is that it abuses
		835	an internal flag to store wether a filename is Unicode or ANSI, but that
		836	flag is used for somethign else in the perl core, so there is no way to
		837	detect wether a filename is ANSI or Unicode-encoded). The BDB module
		838	tries to work around this issue by assuming that the filename is an ANSI
		839	filename and BDB was built for unicode support.
		840
693	=head1 KNOWN BUGS	841	=head1 KNOWN BUGS
694		842
695	Known bugs will be fixed in the next release, except:	843	Known bugs will be fixed in the next release, except:
696		844
697	If you use a transaction in any request, and the request returns	845	If you use a transaction in any request, and the request returns
…		…
699	TXN_DEADLOCK flag will be set on the transaction. See C<db_txn_finish>,	847	TXN_DEADLOCK flag will be set on the transaction. See C<db_txn_finish>,
700	above.	848	above.
701		849
702	=head1 SEE ALSO	850	=head1 SEE ALSO
703		851
704	L<Coro::BDB>, L<IO::AIO>.	852	L<AnyEvent::BDB> (event loop integration), L<Coro::BDB> (more natural
		853	syntax), L<IO::AIO> (nice to have).
705		854
706	=head1 AUTHOR	855	=head1 AUTHOR
707		856
708	Marc Lehmann <schmorp@schmorp.de>	857	Marc Lehmann <schmorp@schmorp.de>
709	http://home.schmorp.de/	858	http://home.schmorp.de/

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Comparing BDB/BDB.pm (file contents): Revision 1.24 by root, Mon Dec 10 04:57:14 2007 UTC vs. Revision 1.55 by root, Sun Jan 4 10:48:15 2009 UTC

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Comparing BDB/BDB.pm (file contents):
Revision 1.24 by root, Mon Dec 10 04:57:14 2007 UTC vs.
Revision 1.55 by root, Sun Jan 4 10:48:15 2009 UTC