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

Comparing BDB/BDB.pm (file contents):
Revision 1.20 by root, Fri Dec 7 13:14:41 2007 UTC vs.
Revision 1.57 by root, Tue Jul 14 19:29:23 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:
…		…
101		103
102	=cut	104	=cut
103		105
104	package BDB;	106	package BDB;
105		107
106	no warnings;	108	use common::sense;
107	use strict 'vars';
108		109
109	use base 'Exporter';	110	use base 'Exporter';
110		111
		112	our $VERSION;
		113
111	BEGIN {	114	BEGIN {
112	our $VERSION = '1.2';	115	$VERSION = '1.84';
113		116
114	our @BDB_REQ = qw(	117	our @BDB_REQ = qw(
115	db_env_open db_env_close db_env_txn_checkpoint db_env_lock_detect	118	db_env_open db_env_close db_env_txn_checkpoint db_env_lock_detect
116	db_env_memp_sync db_env_memp_trickle	119	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	120	db_env_log_archive
		121	db_open db_close db_compact db_sync db_verify db_upgrade
		122	db_put db_exists db_get db_pget db_del db_key_range
118	db_txn_commit db_txn_abort db_txn_finish	123	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	124	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	125	db_sequence_open db_sequence_close
121	db_sequence_get db_sequence_remove	126	db_sequence_get db_sequence_remove
122	);	127	);
…		…
130		135
131	require XSLoader;	136	require XSLoader;
132	XSLoader::load ("BDB", $VERSION);	137	XSLoader::load ("BDB", $VERSION);
133	}	138	}
134		139
135	=head2 BERKELEYDB FUNCTIONS	140	=head1 BERKELEYDB FUNCTIONS
136		141
137	All of these are functions. The create functions simply return a new	142	All of these are functions. The create functions simply return a new
138	object and never block. All the remaining functions all take an optional	143	object and never block. All the remaining functions take an optional
139	callback as last argument. If it is missing, then the fucntion will be	144	callback as last argument. If it is missing, then the function will be
140	executed synchronously.	145	executed synchronously. In both cases, C<$!> will reflect the return value
		146	of the function.
141		147
142	BDB functions that cannot block (mostly functions that manipulate	148	BDB functions that cannot block (mostly functions that manipulate
143	settings) are method calls on the relevant objects, so the rule of thumb	149	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	150	is: if it's a method, it's not blocking, if it's a function, it takes a
145	callback as last argument.	151	callback as last argument.
146		152
147	In the following, C<$int> signifies an integer return value,	153	In the following, C<$int> signifies an integer return value,
148	C<octetstring> is a "binary string" (i.e. a perl string with no character	154	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	155	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.	156	floating point value.
151		157
152	The C<SV *> types are generic perl scalars (for input and output of data	158	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	159	values).
154	when the request is completed.
155		160
156	The various C<DB_ENV> etc. arguments are handles return by	161	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	162	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>	163	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.	164	for them, resulting a NULL pointer on the C level.
160		165
		166	The C<SV *callback> is the optional callback function to call when the
		167	request is completed. This last callback argument is special: the callback
		168	is simply the last argument passed. If there are "optional" arguments
		169	before the callback they can be left out. The callback itself can be left
		170	out or specified as C<undef>, in which case the function will be executed
		171	synchronously.
		172
		173	For example, C<db_env_txn_checkpoint> usually is called with all integer
		174	arguments zero. These can be left out, so all of these specify a call
		175	to C<< DB_ENV->txn_checkpoint >>, to be executed asynchronously with a
		176	callback to be called:
		177
		178	db_env_txn_checkpoint $db_env, 0, 0, 0, sub { };
		179	db_env_txn_checkpoint $db_env, 0, 0, sub { };
		180	db_env_txn_checkpoint $db_env, sub { };
		181
		182	While these all specify a call to C<< DB_ENV->txn_checkpoint >> to be
		183	executed synchronously:
		184
		185	db_env_txn_checkpoint $db_env, 0, 0, 0, undef;
		186	db_env_txn_checkpoint $db_env, 0, 0, 0;
		187	db_env_txn_checkpoint $db_env, 0;
		188
161	=head3 BDB functions	189	=head2 BDB functions
162		190
163	Functions in the BDB namespace, exported by default:	191	Functions in the BDB namespace, exported by default:
164		192
165	$env = db_env_create (U32 env_flags = 0)	193	$env = db_env_create (U32 env_flags = 0)
166	flags: RPCCLIENT	194	flags: RPCCLIENT
167		195
168	db_env_open (DB_ENV env, octetstring db_home, U32 open_flags, int mode, SV callback = &PL_sv_undef)	196	db_env_open (DB_ENV env, bdb_filename db_home, U32 open_flags, int mode, SV callback = 0)
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	197	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)	198	db_env_close (DB_ENV env, U32 flags = 0, SV callback = 0)
171	db_env_txn_checkpoint (DB_ENV env, U32 kbyte = 0, U32 min = 0, U32 flags = 0, SV callback = &PL_sv_undef)	199	db_env_txn_checkpoint (DB_ENV env, U32 kbyte = 0, U32 min = 0, U32 flags = 0, SV callback = 0)
172	flags: FORCE	200	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)	201	db_env_lock_detect (DB_ENV env, U32 flags = 0, U32 atype = DB_LOCK_DEFAULT, SV dummy = 0, SV *callback = 0)
174	atype: LOCK_DEFAULT LOCK_EXPIRE LOCK_MAXLOCKS LOCK_MAXWRITE LOCK_MINLOCKS LOCK_MINWRITE LOCK_OLDEST LOCK_RANDOM LOCK_YOUNGEST	202	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)	203	db_env_memp_sync (DB_ENV env, SV dummy = 0, SV *callback = 0)
176	db_env_memp_trickle (DB_ENV env, int percent, SV dummy = 0, SV *callback = &PL_sv_undef)	204	db_env_memp_trickle (DB_ENV env, int percent, SV dummy = 0, SV *callback = 0)
		205	db_env_dbremove (DB_ENV env, DB_TXN_ornull txnid, bdb_filename file, bdb_filename database, U32 flags = 0, SV *callback = 0)
		206	db_env_dbrename (DB_ENV env, DB_TXN_ornull txnid, bdb_filename file, bdb_filename database, bdb_filename newname, U32 flags = 0, SV *callback = 0)
		207	db_env_log_archive (DB_ENV env, SV listp, U32 flags = 0, SV *callback = 0)
177		208
178	$db = db_create (DB_ENV *env = 0, U32 flags = 0)	209	$db = db_create (DB_ENV *env = 0, U32 flags = 0)
179	flags: XA_CREATE	210	flags: XA_CREATE
180		211
181	db_open (DB db, DB_TXN_ornull txnid, octetstring file, octetstring database, int type, U32 flags, int mode, SV *callback = &PL_sv_undef)	212	db_open (DB db, DB_TXN_ornull txnid, bdb_filename file, bdb_filename database, int type, U32 flags, int mode, SV *callback = 0)
182	flags: AUTO_COMMIT CREATE EXCL MULTIVERSION NOMMAP RDONLY READ_UNCOMMITTED THREAD TRUNCATE	213	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)	214	db_close (DB db, U32 flags = 0, SV callback = 0)
184	flags: DB_NOSYNC	215	flags: DB_NOSYNC
		216	db_verify (DB db, bdb_filename file, bdb_filename database = 0, SV dummy = 0, U32 flags = 0, SV *callback = 0)
		217	db_upgrade (DB db, bdb_filename file, U32 flags = 0, SV callback = 0)
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 = 0)
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 = 0)
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 = 0)
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 = 0)
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 = 0)
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 = 0)
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 = 0)
196	db_txn_commit (DB_TXN txn, U32 flags = 0, SV callback = &PL_sv_undef)	230	db_txn_commit (DB_TXN txn, U32 flags = 0, SV callback = 0)
197	flags: TXN_NOSYNC TXN_SYNC	231	flags: TXN_NOSYNC TXN_SYNC
198	db_txn_abort (DB_TXN txn, SV callback = &PL_sv_undef)	232	db_txn_abort (DB_TXN txn, SV callback = 0)
199		233
200	db_c_close (DBC dbc, SV callback = &PL_sv_undef)	234	db_c_close (DBC dbc, SV callback = 0)
201	db_c_count (DBC dbc, SV count, U32 flags = 0, SV *callback = &PL_sv_undef)	235	db_c_count (DBC dbc, SV count, U32 flags = 0, SV *callback = 0)
202	db_c_put (DBC dbc, SV key, SV data, U32 flags = 0, SV callback = &PL_sv_undef)	236	db_c_put (DBC dbc, SV key, SV data, U32 flags = 0, SV callback = 0)
203	flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA	237	flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA
204	db_c_get (DBC dbc, SV key, SV data, U32 flags = 0, SV callback = &PL_sv_undef)	238	db_c_get (DBC dbc, SV key, SV data, U32 flags = 0, SV callback = 0)
205	flags: CURRENT FIRST GET_BOTH GET_BOTH_RANGE GET_RECNO JOIN_ITEM LAST NEXT NEXT_DUP NEXT_NODUP PREV PREV_DUP PREV_NODUP SET SET_RANGE SET_RECNO READ_UNCOMMITTED MULTIPLE MULTIPLE_KEY RMW	239	flags: CURRENT FIRST GET_BOTH GET_BOTH_RANGE GET_RECNO JOIN_ITEM LAST NEXT NEXT_DUP NEXT_NODUP PREV PREV_DUP PREV_NODUP SET SET_RANGE SET_RECNO READ_UNCOMMITTED MULTIPLE MULTIPLE_KEY RMW
206	db_c_pget (DBC dbc, SV key, SV pkey, SV data, U32 flags = 0, SV *callback = &PL_sv_undef)	240	db_c_pget (DBC dbc, SV key, SV pkey, SV data, U32 flags = 0, SV *callback = 0)
207	db_c_del (DBC dbc, U32 flags = 0, SV callback = &PL_sv_undef)	241	db_c_del (DBC dbc, U32 flags = 0, SV callback = 0)
208		242
209	db_sequence_open (DB_SEQUENCE seq, DB_TXN_ornull txnid, SV key, U32 flags = 0, SV callback = &PL_sv_undef)	243	db_sequence_open (DB_SEQUENCE seq, DB_TXN_ornull txnid, SV key, U32 flags = 0, SV callback = 0)
210	flags: CREATE EXCL	244	flags: CREATE EXCL
211	db_sequence_close (DB_SEQUENCE seq, U32 flags = 0, SV callback = &PL_sv_undef)	245	db_sequence_close (DB_SEQUENCE seq, U32 flags = 0, SV callback = 0)
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 = 0)
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 = 0)
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 = 0)
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<< $txn->failed >> method to check wether a transaction
250	has failed in this way and abort further processing (excluding	284	has failed in this way and abort further processing (excluding
251	C<db_txn_finish>).	285	C<db_txn_finish>).
252		286
		287
253	=head3 DB_ENV/database environment methods	288	=head2 DB_ENV/database environment methods
254		289
255	Methods available on DB_ENV/$env handles:	290	Methods available on DB_ENV/$env handles:
256		291
257	DESTROY (DB_ENV_ornull *env)	292	DESTROY (DB_ENV_ornull *env)
258	CODE:	293	CODE:
…		…
262	$int = $env->set_data_dir (const char *dir)	297	$int = $env->set_data_dir (const char *dir)
263	$int = $env->set_tmp_dir (const char *dir)	298	$int = $env->set_tmp_dir (const char *dir)
264	$int = $env->set_lg_dir (const char *dir)	299	$int = $env->set_lg_dir (const char *dir)
265	$int = $env->set_shm_key (long shm_key)	300	$int = $env->set_shm_key (long shm_key)
266	$int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0)	301	$int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0)
267	$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)
268	$env->set_errfile (FILE *errfile = 0)	305	$env->set_errfile (FILE *errfile = 0)
269	$env->set_msgfile (FILE *msgfile = 0)	306	$env->set_msgfile (FILE *msgfile = 0)
270	$int = $env->set_verbose (U32 which, int onoff = 1)	307	$int = $env->set_verbose (U32 which, int onoff = 1)
271	$int = $env->set_encrypt (const char *password, U32 flags = 0)	308	$int = $env->set_encrypt (const char *password, U32 flags = 0)
272	$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)
…		…
284	$int = $env->mutex_set_max (U32 max)	321	$int = $env->mutex_set_max (U32 max)
285	$int = $env->mutex_set_align (U32 align)	322	$int = $env->mutex_set_align (U32 align)
286		323
287	$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)
288	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)
289		327
290	=head4 Example:	328	=head3 Example:
291		329
292	use AnyEvent;	330	use AnyEvent;
293	use BDB;	331	use BDB;
294		332
295	our $FH; open $FH, "<&=" . BDB::poll_fileno;	333	our $FH; open $FH, "<&=" . BDB::poll_fileno;
…		…
307	0600;	345	0600;
308		346
309	$env->set_flags (BDB::AUTO_COMMIT \| BDB::TXN_NOSYNC, 1);	347	$env->set_flags (BDB::AUTO_COMMIT \| BDB::TXN_NOSYNC, 1);
310		348
311		349
312	=head3 DB/database methods	350	=head2 DB/database methods
313		351
314	Methods available on DB/$db handles:	352	Methods available on DB/$db handles:
315		353
316	DESTROY (DB_ornull *db)	354	DESTROY (DB_ornull *db)
317	CODE:	355	CODE:
…		…
343		381
344	$dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0)	382	$dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0)
345	flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT	383	flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT
346	$seq = $db->sequence (U32 flags = 0)	384	$seq = $db->sequence (U32 flags = 0)
347		385
348	=head4 Example:	386	=head3 Example:
349		387
350	my $db = db_create $env;	388	my $db = db_create $env;
351	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;
352		390
353	for (1..1000) {	391	for (1..1000) {
…		…
360	db_del $db, undef, "key $_" for 1..1000;	398	db_del $db, undef, "key $_" for 1..1000;
361		399
362	db_sync $db;	400	db_sync $db;
363		401
364		402
365	=head3 DB_TXN/transaction methods	403	=head2 DB_TXN/transaction methods
366		404
367	Methods available on DB_TXN/$txn handles:	405	Methods available on DB_TXN/$txn handles:
368		406
369	DESTROY (DB_TXN_ornull *txn)	407	DESTROY (DB_TXN_ornull *txn)
370	CODE:	408	CODE:
…		…
376		414
377	$bool = $txn->failed	415	$bool = $txn->failed
378	# see db_txn_finish documentation, above	416	# see db_txn_finish documentation, above
379		417
380		418
381	=head3 DBC/cursor methods	419	=head2 DBC/cursor methods
382		420
383	Methods available on DBC/$dbc handles:	421	Methods available on DBC/$dbc handles:
384		422
385	DESTROY (DBC_ornull *dbc)	423	DESTROY (DBC_ornull *dbc)
386	CODE:	424	CODE:
387	if (dbc)	425	if (dbc)
388	dbc->c_close (dbc);	426	dbc->c_close (dbc);
389		427
		428	$int = $cursor->set_priority ($priority = PRIORITY_*) (v4.6)
		429
390	=head4 Example:	430	=head3 Example:
391		431
392	my $c = $db->cursor;	432	my $c = $db->cursor;
393		433
394	for (;;) {	434	for (;;) {
395	db_c_get $c, my $key, my $data, BDB::NEXT;	435	db_c_get $c, my $key, my $data, BDB::NEXT;
…		…
398	}	438	}
399		439
400	db_c_close $c;	440	db_c_close $c;
401		441
402		442
403	=head3 DB_SEQUENCE/sequence methods	443	=head2 DB_SEQUENCE/sequence methods
404		444
405	Methods available on DB_SEQUENCE/$seq handles:	445	Methods available on DB_SEQUENCE/$seq handles:
406		446
407	DESTROY (DB_SEQUENCE_ornull *seq)	447	DESTROY (DB_SEQUENCE_ornull *seq)
408	CODE:	448	CODE:
…		…
413	$int = $seq->set_cachesize (U32 size)	453	$int = $seq->set_cachesize (U32 size)
414	$int = $seq->set_flags (U32 flags)	454	$int = $seq->set_flags (U32 flags)
415	flags: SEQ_DEC SEQ_INC SEQ_WRAP	455	flags: SEQ_DEC SEQ_INC SEQ_WRAP
416	$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)
417		457
418	=head4 Example:	458	=head3 Example:
419		459
420	my $seq = $db->sequence;	460	my $seq = $db->sequence;
421		461
422	db_sequence_open $seq, undef, "seq", BDB::CREATE;	462	db_sequence_open $seq, undef, "seq", BDB::CREATE;
423	db_sequence_get $seq, undef, 1, my $value;	463	db_sequence_get $seq, undef, 1, my $value;
424		464
425		465
426	=head2 SUPPORT FUNCTIONS	466	=head1 SUPPORT FUNCTIONS
427		467
428	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	468	=head2 EVENT PROCESSING AND EVENT LOOP INTEGRATION
429		469
430	=over 4	470	=over 4
		471
		472	=item $msg = BDB::strerror [$errno]
		473
		474	Returns the string corresponding to the given errno value. If no argument
		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<$!>.
431		479
432	=item $fileno = BDB::poll_fileno	480	=item $fileno = BDB::poll_fileno
433		481
434	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
435	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
…		…
512	BDB::poll_wait, BDB::poll_cb	560	BDB::poll_wait, BDB::poll_cb
513	while BDB::nreqs;	561	while BDB::nreqs;
514		562
515	=back	563	=back
516		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
517	=head3 CONTROLLING THE NUMBER OF THREADS	631	=head2 CONTROLLING THE NUMBER OF THREADS
518		632
519	=over 4	633	=over 4
520		634
521	=item BDB::min_parallel $nthreads	635	=item BDB::min_parallel $nthreads
522		636
…		…
583		697
584	You can still queue as many requests as you want. Therefore,	698	You can still queue as many requests as you want. Therefore,
585	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
586	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).
587		701
588	=item BDB::set_sync_prepare $cb	702	=item $old_cb = BDB::set_sync_prepare $cb
589		703
590	Sets a callback that is called whenever a request is created without an	704	Sets a callback that is called whenever a request is created without an
591	explicit callback. It has to return two code references. The first is used	705	explicit callback. It has to return two code references. The first is used
592	as the request callback, and the second is called to wait until the first	706	as the request callback (it should save the return status), and the second
593	callback has been called. The default implementation works like this:	707	is called to wait until the first callback has been called (it must set
		708	C<$!> 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:
594		715
595	sub {	716	sub {
596	my $status;	717	my $status;
597	(	718	(
598	sub { $status = $! },	719	sub { $status = $! },
599	sub { BDB::poll while !defined $status; $! = $status },	720	sub { BDB::poll while !defined $status; $! = $status },
600	)	721	)
601	}	722	}
602		723
		724	It works by polling for results till the request has finished and then
		725	sets C<$!> 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
603	=back	732	=back
604		733
605	=head3 STATISTICAL INFORMATION	734	=head2 STATISTICAL INFORMATION
606		735
607	=over 4	736	=over 4
608		737
609	=item BDB::nreqs	738	=item BDB::nreqs
610		739
…		…
628		757
629	=back	758	=back
630		759
631	=cut	760	=cut
632		761
633	set_sync_prepare {	762	set_sync_prepare (undef);
634	my $status;
635	(
636	sub {
637	$status = $!;
638	},
639	sub {
640	BDB::poll while !defined $status;
641	$! = $status;
642	},
643	)
644	};
645		763
646	min_parallel 8;	764	min_parallel 8;
647		765
648	END { flush }	766	END { flush }
649		767
650	1;	768	1;
651		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
652	=head2 FORK BEHAVIOUR	793	=head1 FORK BEHAVIOUR
653		794
654	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:
655		796
656	Before the fork, BDB enters a quiescent state where no requests	797	Before the fork, BDB enters a quiescent state where no requests
657	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
…		…
663		804
664	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
665	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
666	yet.	807	yet.
667		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
668	=head2 MEMORY USAGE	813	=head1 MEMORY USAGE
669		814
670	Per-request usage:	815	Per-request usage:
671		816
672	Each aio request uses - depending on your architecture - around 100-200	817	Each aio request uses - depending on your architecture - around 100-200
673	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
…		…
682		827
683	In the execution phase, some aio requests require more memory for	828	In the execution phase, some aio requests require more memory for
684	temporary buffers, and each thread requires a stack and other data	829	temporary buffers, and each thread requires a stack and other data
685	structures (usually around 16k-128k, depending on the OS).	830	structures (usually around 16k-128k, depending on the OS).
686		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
687	=head1 KNOWN BUGS	841	=head1 KNOWN BUGS
688		842
689	Known bugs will be fixed in the next release, except:	843	Known bugs will be fixed in the next release, except:
690		844
691	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
…		…
693	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>,
694	above.	848	above.
695		849
696	=head1 SEE ALSO	850	=head1 SEE ALSO
697		851
698	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).
699		854
700	=head1 AUTHOR	855	=head1 AUTHOR
701		856
702	Marc Lehmann <schmorp@schmorp.de>	857	Marc Lehmann <schmorp@schmorp.de>
703	http://home.schmorp.de/	858	http://home.schmorp.de/

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Comparing BDB/BDB.pm (file contents): Revision 1.20 by root, Fri Dec 7 13:14:41 2007 UTC vs. Revision 1.57 by root, Tue Jul 14 19:29:23 2009 UTC

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Comparing BDB/BDB.pm (file contents):
Revision 1.20 by root, Fri Dec 7 13:14:41 2007 UTC vs.
Revision 1.57 by root, Tue Jul 14 19:29:23 2009 UTC