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

Comparing BDB/BDB.pm (file contents):
Revision 1.19 by root, Wed Dec 5 13:01:46 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 = '1.2';	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
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", $VERSION);
133	}	139	}
134		140
135	=head2 BERKELEYDB FUNCTIONS	141	=head1 BERKELEYDB FUNCTIONS
136		142
137	All of these are functions. The create functions simply return a new	143	All of these are functions. The create functions simply return a new
138	object and never block. All the remaining functions all take an optional	144	object and never block. All the remaining functions take an optional
139	callback as last argument. If it is missing, then the fucntion will be	145	callback as last argument. If it is missing, then the function will be
140	executed synchronously.	146	executed synchronously. In both cases, C<$!> will reflect the return value
		147	of the function.
141		148
142	BDB functions that cannot block (mostly functions that manipulate	149	BDB functions that cannot block (mostly functions that manipulate
143	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
144	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
145	callback as last argument.	152	callback as last argument.
146		153
147	In the following, C<$int> signifies an integer return value,	154	In the following, C<$int> signifies an integer return value,
148	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),
149	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
150	integer, C<NV> is a floating point value.	157	floating point value.
151		158
152	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
153	values), and the C<SV *callback> is the optional callback function to call	160	values).
154	when the request is completed.
155		161
156	The various C<DB_ENV> etc. arguments are handles return by	162	The various C<DB_ENV> etc. arguments are handles return by
157	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
158	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>
159	for them, resulting a NULL pointer on the C level.	165	for them, resulting a NULL pointer on the C level.
160		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
161	=head3 BDB functions	190	=head2 BDB functions
162		191
163	Functions in the BDB namespace, exported by default:	192	Functions in the BDB namespace, exported by default:
164		193
165	$env = db_env_create (U32 env_flags = 0)	194	$env = db_env_create (U32 env_flags = 0)
166	flags: RPCCLIENT	195	flags: RPCCLIENT
167		196
168	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)
169	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
170	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)
171	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)
172	flags: FORCE	201	flags: FORCE
173	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)
174	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
175	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)
176	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)
177		209
178	$db = db_create (DB_ENV *env = 0, U32 flags = 0)	210	$db = db_create (DB_ENV *env = 0, U32 flags = 0)
179	flags: XA_CREATE	211	flags: XA_CREATE
180		212
181	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)
182	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
183	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)
184	flags: DB_NOSYNC	216	flags: DB_NOSYNC
		217	db_upgrade (DB db, bdb_filename file, U32 flags = 0, SV callback = &PL_sv_undef)
185	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)
186	flags: FREELIST_ONLY FREE_SPACE	219	flags: FREELIST_ONLY FREE_SPACE
187	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)
188	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)
189	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)
190	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)
191	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)
192	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
193	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)
194	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
195	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)
…		…
212	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)
213	flags: TXN_NOSYNC	247	flags: TXN_NOSYNC
214	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)
215	flags: TXN_NOSYNC	249	flags: TXN_NOSYNC
216		250
217	=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)
218		252
219	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
220	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
221	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
222	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
…		…
248		282
249	You can use the C<< $txn->failed >> method to check wether a transaction	283	You can use the C<< $txn->failed >> method to check wether a transaction
250	has failed in this way and abort further processing (excluding	284	has failed in this way and abort further processing (excluding
251	C<db_txn_finish>).	285	C<db_txn_finish>).
252		286
253	=head3 DB_ENV/database environment methods	287	=head2 DB_ENV/database environment methods
254		288
255	Methods available on DB_ENV/$env handles:	289	Methods available on DB_ENV/$env handles:
256		290
257	DESTROY (DB_ENV_ornull *env)	291	DESTROY (DB_ENV_ornull *env)
258	CODE:	292	CODE:
…		…
262	$int = $env->set_data_dir (const char *dir)	296	$int = $env->set_data_dir (const char *dir)
263	$int = $env->set_tmp_dir (const char *dir)	297	$int = $env->set_tmp_dir (const char *dir)
264	$int = $env->set_lg_dir (const char *dir)	298	$int = $env->set_lg_dir (const char *dir)
265	$int = $env->set_shm_key (long shm_key)	299	$int = $env->set_shm_key (long shm_key)
266	$int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0)	300	$int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0)
267	$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)
268	$env->set_errfile (FILE *errfile = 0)	304	$env->set_errfile (FILE *errfile = 0)
269	$env->set_msgfile (FILE *msgfile = 0)	305	$env->set_msgfile (FILE *msgfile = 0)
270	$int = $env->set_verbose (U32 which, int onoff = 1)	306	$int = $env->set_verbose (U32 which, int onoff = 1)
271	$int = $env->set_encrypt (const char *password, U32 flags = 0)	307	$int = $env->set_encrypt (const char *password, U32 flags = 0)
272	$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)
…		…
277	$int = $env->set_lk_max_lockers (U32 max)	313	$int = $env->set_lk_max_lockers (U32 max)
278	$int = $env->set_lk_max_locks (U32 max)	314	$int = $env->set_lk_max_locks (U32 max)
279	$int = $env->set_lk_max_objects (U32 max)	315	$int = $env->set_lk_max_objects (U32 max)
280	$int = $env->set_lg_bsize (U32 max)	316	$int = $env->set_lg_bsize (U32 max)
281	$int = $env->set_lg_max (U32 max)	317	$int = $env->set_lg_max (U32 max)
		318	$int = $env->mutex_set_increment (U32 increment)
		319	$int = $env->mutex_set_tas_spins (U32 tas_spins)
		320	$int = $env->mutex_set_max (U32 max)
		321	$int = $env->mutex_set_align (U32 align)
282		322
283	$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)
284	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)
285		326
286	=head4 Example:	327	=head3 Example:
287		328
288	use AnyEvent;	329	use AnyEvent;
289	use BDB;	330	use BDB;
290		331
291	our $FH; open $FH, "<&=" . BDB::poll_fileno;	332	our $FH; open $FH, "<&=" . BDB::poll_fileno;
…		…
303	0600;	344	0600;
304		345
305	$env->set_flags (BDB::AUTO_COMMIT \| BDB::TXN_NOSYNC, 1);	346	$env->set_flags (BDB::AUTO_COMMIT \| BDB::TXN_NOSYNC, 1);
306		347
307		348
308	=head3 DB/database methods	349	=head2 DB/database methods
309		350
310	Methods available on DB/$db handles:	351	Methods available on DB/$db handles:
311		352
312	DESTROY (DB_ornull *db)	353	DESTROY (DB_ornull *db)
313	CODE:	354	CODE:
…		…
339		380
340	$dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0)	381	$dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0)
341	flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT	382	flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT
342	$seq = $db->sequence (U32 flags = 0)	383	$seq = $db->sequence (U32 flags = 0)
343		384
344	=head4 Example:	385	=head3 Example:
345		386
346	my $db = db_create $env;	387	my $db = db_create $env;
347	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;
348		389
349	for (1..1000) {	390	for (1..1000) {
…		…
356	db_del $db, undef, "key $_" for 1..1000;	397	db_del $db, undef, "key $_" for 1..1000;
357		398
358	db_sync $db;	399	db_sync $db;
359		400
360		401
361	=head3 DB_TXN/transaction methods	402	=head2 DB_TXN/transaction methods
362		403
363	Methods available on DB_TXN/$txn handles:	404	Methods available on DB_TXN/$txn handles:
364		405
365	DESTROY (DB_TXN_ornull *txn)	406	DESTROY (DB_TXN_ornull *txn)
366	CODE:	407	CODE:
…		…
372		413
373	$bool = $txn->failed	414	$bool = $txn->failed
374	# see db_txn_finish documentation, above	415	# see db_txn_finish documentation, above
375		416
376		417
377	=head3 DBC/cursor methods	418	=head2 DBC/cursor methods
378		419
379	Methods available on DBC/$dbc handles:	420	Methods available on DBC/$dbc handles:
380		421
381	DESTROY (DBC_ornull *dbc)	422	DESTROY (DBC_ornull *dbc)
382	CODE:	423	CODE:
383	if (dbc)	424	if (dbc)
384	dbc->c_close (dbc);	425	dbc->c_close (dbc);
385		426
		427	$int = $cursor->set_priority ($priority = PRIORITY_*) (v4.6)
		428
386	=head4 Example:	429	=head3 Example:
387		430
388	my $c = $db->cursor;	431	my $c = $db->cursor;
389		432
390	for (;;) {	433	for (;;) {
391	db_c_get $c, my $key, my $data, BDB::NEXT;	434	db_c_get $c, my $key, my $data, BDB::NEXT;
…		…
394	}	437	}
395		438
396	db_c_close $c;	439	db_c_close $c;
397		440
398		441
399	=head3 DB_SEQUENCE/sequence methods	442	=head2 DB_SEQUENCE/sequence methods
400		443
401	Methods available on DB_SEQUENCE/$seq handles:	444	Methods available on DB_SEQUENCE/$seq handles:
402		445
403	DESTROY (DB_SEQUENCE_ornull *seq)	446	DESTROY (DB_SEQUENCE_ornull *seq)
404	CODE:	447	CODE:
…		…
409	$int = $seq->set_cachesize (U32 size)	452	$int = $seq->set_cachesize (U32 size)
410	$int = $seq->set_flags (U32 flags)	453	$int = $seq->set_flags (U32 flags)
411	flags: SEQ_DEC SEQ_INC SEQ_WRAP	454	flags: SEQ_DEC SEQ_INC SEQ_WRAP
412	$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)
413		456
414	=head4 Example:	457	=head3 Example:
415		458
416	my $seq = $db->sequence;	459	my $seq = $db->sequence;
417		460
418	db_sequence_open $seq, undef, "seq", BDB::CREATE;	461	db_sequence_open $seq, undef, "seq", BDB::CREATE;
419	db_sequence_get $seq, undef, 1, my $value;	462	db_sequence_get $seq, undef, 1, my $value;
420		463
421		464
422	=head2 SUPPORT FUNCTIONS	465	=head1 SUPPORT FUNCTIONS
423		466
424	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	467	=head2 EVENT PROCESSING AND EVENT LOOP INTEGRATION
425		468
426	=over 4	469	=over 4
		470
		471	=item $msg = BDB::strerror [$errno]
		472
		473	Returns the string corresponding to the given errno value. If no argument
		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<$!>.
427		478
428	=item $fileno = BDB::poll_fileno	479	=item $fileno = BDB::poll_fileno
429		480
430	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
431	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
…		…
508	BDB::poll_wait, BDB::poll_cb	559	BDB::poll_wait, BDB::poll_cb
509	while BDB::nreqs;	560	while BDB::nreqs;
510		561
511	=back	562	=back
512		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
513	=head3 CONTROLLING THE NUMBER OF THREADS	630	=head2 CONTROLLING THE NUMBER OF THREADS
514		631
515	=over 4	632	=over 4
516		633
517	=item BDB::min_parallel $nthreads	634	=item BDB::min_parallel $nthreads
518		635
…		…
579		696
580	You can still queue as many requests as you want. Therefore,	697	You can still queue as many requests as you want. Therefore,
581	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
582	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).
583		700
584	=item BDB::set_sync_prepare $cb	701	=item $old_cb = BDB::set_sync_prepare $cb
585		702
586	Sets a callback that is called whenever a request is created without an	703	Sets a callback that is called whenever a request is created without an
587	explicit callback. It has to return two code references. The first is used	704	explicit callback. It has to return two code references. The first is used
588	as the request callback, and the second is called to wait until the first	705	as the request callback (it should save the return status), and the second
589	callback has been called. The default implementation works like this:	706	is called to wait until the first callback has been called (it must set
		707	C<$!> 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:
590		714
591	sub {	715	sub {
592	my $status;	716	my $status;
593	(	717	(
594	sub { $status = $! },	718	sub { $status = $! },
595	sub { BDB::poll while !defined $status; $! = $status },	719	sub { BDB::poll while !defined $status; $! = $status },
596	)	720	)
597	}	721	}
598		722
		723	It works by polling for results till the request has finished and then
		724	sets C<$!> 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
599	=back	731	=back
600		732
601	=head3 STATISTICAL INFORMATION	733	=head2 STATISTICAL INFORMATION
602		734
603	=over 4	735	=over 4
604		736
605	=item BDB::nreqs	737	=item BDB::nreqs
606		738
…		…
624		756
625	=back	757	=back
626		758
627	=cut	759	=cut
628		760
629	set_sync_prepare {	761	set_sync_prepare (undef);
630	my $status;
631	(
632	sub {
633	$status = $!;
634	},
635	sub {
636	BDB::poll while !defined $status;
637	$! = $status;
638	},
639	)
640	};
641		762
642	min_parallel 8;	763	min_parallel 8;
643		764
644	END { flush }	765	END { flush }
645		766
646	1;	767	1;
647		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
648	=head2 FORK BEHAVIOUR	792	=head1 FORK BEHAVIOUR
649		793
650	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:
651		795
652	Before the fork, BDB enters a quiescent state where no requests	796	Before the fork, BDB enters a quiescent state where no requests
653	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
…		…
659		803
660	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
661	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
662	yet.	806	yet.
663		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
664	=head2 MEMORY USAGE	812	=head1 MEMORY USAGE
665		813
666	Per-request usage:	814	Per-request usage:
667		815
668	Each aio request uses - depending on your architecture - around 100-200	816	Each aio request uses - depending on your architecture - around 100-200
669	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
…		…
678		826
679	In the execution phase, some aio requests require more memory for	827	In the execution phase, some aio requests require more memory for
680	temporary buffers, and each thread requires a stack and other data	828	temporary buffers, and each thread requires a stack and other data
681	structures (usually around 16k-128k, depending on the OS).	829	structures (usually around 16k-128k, depending on the OS).
682		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
683	=head1 KNOWN BUGS	840	=head1 KNOWN BUGS
684		841
685	Known bugs will be fixed in the next release, except:	842	Known bugs will be fixed in the next release, except:
686		843
687	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
…		…
689	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>,
690	above.	847	above.
691		848
692	=head1 SEE ALSO	849	=head1 SEE ALSO
693		850
694	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).
695		853
696	=head1 AUTHOR	854	=head1 AUTHOR
697		855
698	Marc Lehmann <schmorp@schmorp.de>	856	Marc Lehmann <schmorp@schmorp.de>
699	http://home.schmorp.de/	857	http://home.schmorp.de/

Diff Legend

-–
+Removed lines
-+
+Added lines
-<
+Changed lines
->
+Changed lines

Comparing BDB/BDB.pm (file contents): Revision 1.19 by root, Wed Dec 5 13:01:46 2007 UTC vs. Revision 1.53 by root, Tue Oct 21 02:21:25 2008 UTC

Diff Legend

Comparing BDB/BDB.pm (file contents):
Revision 1.19 by root, Wed Dec 5 13:01:46 2007 UTC vs.
Revision 1.53 by root, Tue Oct 21 02:21:25 2008 UTC