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Comparing BDB/BDB.pm (file contents):
Revision 1.31 by root, Sun Jan 13 09:43:21 2008 UTC vs.
Revision 1.58 by root, Fri Jul 17 04:18:49 2009 UTC

… …
27 db_sync $db; 27 db_sync $db;
28 28
29 # when you also use Coro, management is easy: 29 # when you also use Coro, management is easy:
30 use Coro::BDB; 30 use Coro::BDB;
31 31
32 # automatic result processing with AnyEvent: 32 # automatic event loop integration with AnyEvent:
33 our $FH; open $FH, "<&=" . BDB::poll_fileno; 33 use AnyEvent::BDB;
34 our $WATCHER = AnyEvent->io (fh => $FH, poll => 'r', cb => \&BDB::poll_cb);
35 34
36 # automatic result processing with EV: 35 # automatic result processing with EV:
37 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;
38 37
39 # with Glib: 38 # with Glib:
… …
104 103
105=cut 104=cut
106 105
107package BDB; 106package BDB;
108 107
109no warnings; 108use common::sense;
110use strict 'vars';
111 109
112use base 'Exporter'; 110use base 'Exporter';
113 111
112our $VERSION;
113
114BEGIN { 114BEGIN {
115 our $VERSION = '1.43'; 115 $VERSION = '1.84';
116 116
117 our @BDB_REQ = qw( 117 our @BDB_REQ = qw(
118 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
119 db_env_memp_sync db_env_memp_trickle 119 db_env_memp_sync db_env_memp_trickle db_env_dbrename db_env_dbremove
120 db_env_log_archive
120 db_open db_close db_compact db_sync db_upgrade 121 db_open db_close db_compact db_sync db_verify db_upgrade
121 db_put db_get db_pget db_del db_key_range 122 db_put db_exists db_get db_pget db_del db_key_range
122 db_txn_commit db_txn_abort db_txn_finish 123 db_txn_commit db_txn_abort db_txn_finish
123 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
124 db_sequence_open db_sequence_close 125 db_sequence_open db_sequence_close
125 db_sequence_get db_sequence_remove 126 db_sequence_get db_sequence_remove
126 ); 127 );
… …
134 135
135 require XSLoader; 136 require XSLoader;
136 XSLoader::load ("BDB", $VERSION); 137 XSLoader::load ("BDB", $VERSION);
137} 138}
138 139
139=head2 BERKELEYDB FUNCTIONS 140=head1 BERKELEYDB FUNCTIONS
140 141
141All of these are functions. The create functions simply return a new 142All of these are functions. The create functions simply return a new
142object and never block. All the remaining functions all take an optional 143object and never block. All the remaining functions take an optional
143callback as last argument. If it is missing, then the function will be 144callback as last argument. If it is missing, then the function will be
144executed synchronously. In both cases, C<$!> will reflect the return value 145executed synchronously. In both cases, C<$!> will reflect the return value
145of the function. 146of the function.
146 147
147BDB functions that cannot block (mostly functions that manipulate 148BDB functions that cannot block (mostly functions that manipulate
148settings) are method calls on the relevant objects, so the rule of thumb 149settings) are method calls on the relevant objects, so the rule of thumb
149is: if its a method, its not blocking, if its a function, it takes a 150is: if it's a method, it's not blocking, if it's a function, it takes a
150callback as last argument. 151callback as last argument.
151 152
152In the following, C<$int> signifies an integer return value, 153In the following, C<$int> signifies an integer return value,
153C<octetstring> is a "binary string" (i.e. a perl string with no character 154C<bdb_filename> is a "filename" (octets on unix, madness on windows),
154indices >255), C<U32> is an unsigned 32 bit integer, C<int> is some 155C<U32> is an unsigned 32 bit integer, C<int> is some integer, C<NV> is a
155integer, C<NV> is a floating point value. 156floating point value.
156 157
157The C<SV *> types are generic perl scalars (for input and output of data 158Most C<SV *> types are generic perl scalars (for input and output of data
158values), and the C<SV *callback> is the optional callback function to call 159values).
159when the request is completed.
160 160
161The various C<DB_ENV> etc. arguments are handles return by 161The various C<DB_ENV> etc. arguments are handles return by
162C<db_env_create>, C<db_create>, C<txn_begin> and so on. If they have an 162C<db_env_create>, C<db_create>, C<txn_begin> and so on. If they have an
163appended C<_ornull> this means they are optional and you can pass C<undef> 163appended C<_ornull> this means they are optional and you can pass C<undef>
164for them, resulting a NULL pointer on the C level. 164for them, resulting a NULL pointer on the C level.
165 165
166The C<SV *callback> is the optional callback function to call when the
167request is completed. This last callback argument is special: the callback
168is simply the last argument passed. If there are "optional" arguments
169before the callback they can be left out. The callback itself can be left
170out or specified as C<undef>, in which case the function will be executed
171synchronously.
172
173For example, C<db_env_txn_checkpoint> usually is called with all integer
174arguments zero. These can be left out, so all of these specify a call
175to C<< DB_ENV->txn_checkpoint >>, to be executed asynchronously with a
176callback 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
182While these all specify a call to C<< DB_ENV->txn_checkpoint >> to be
183executed 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
166=head3 BDB functions 189=head2 BDB functions
167 190
168Functions in the BDB namespace, exported by default: 191Functions in the BDB namespace, exported by default:
169 192
170 $env = db_env_create (U32 env_flags = 0) 193 $env = db_env_create (U32 env_flags = 0)
171 flags: RPCCLIENT 194 flags: RPCCLIENT
172 195
173 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)
174 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
175 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)
176 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)
177 flags: FORCE 200 flags: FORCE
178 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)
179 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
180 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)
181 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)
182 208
183 $db = db_create (DB_ENV *env = 0, U32 flags = 0) 209 $db = db_create (DB_ENV *env = 0, U32 flags = 0)
184 flags: XA_CREATE 210 flags: XA_CREATE
185 211
186 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)
187 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
188 db_close (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) 214 db_close (DB *db, U32 flags = 0, SV *callback = 0)
189 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)
190 db_upgrade (DB *db, octetstring file, U32 flags = 0, SV *callback = &PL_sv_undef) 217 db_upgrade (DB *db, bdb_filename file, U32 flags = 0, SV *callback = 0)
191 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)
192 flags: FREELIST_ONLY FREE_SPACE 219 flags: FREELIST_ONLY FREE_SPACE
193 db_sync (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) 220 db_sync (DB *db, U32 flags = 0, SV *callback = 0)
194 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)
195 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)
196 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)
197 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)
198 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
199 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)
200 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
201 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)
202 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)
203 flags: TXN_NOSYNC TXN_SYNC 231 flags: TXN_NOSYNC TXN_SYNC
204 db_txn_abort (DB_TXN *txn, SV *callback = &PL_sv_undef) 232 db_txn_abort (DB_TXN *txn, SV *callback = 0)
205 233
206 db_c_close (DBC *dbc, SV *callback = &PL_sv_undef) 234 db_c_close (DBC *dbc, SV *callback = 0)
207 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)
208 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)
209 flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA 237 flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA
210 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)
211 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
212 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)
213 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)
214 242
215 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)
216 flags: CREATE EXCL 244 flags: CREATE EXCL
217 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)
218 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)
219 flags: TXN_NOSYNC 247 flags: TXN_NOSYNC
220 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)
221 flags: TXN_NOSYNC 249 flags: TXN_NOSYNC
222 250
223=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)
224 252
225This is not actually a Berkeley DB function but a BDB module 253This is not actually a Berkeley DB function but a BDB module
226extension. The background for this exytension is: It is very annoying to 254extension. The background for this exytension is: It is very annoying to
227have to check every single BDB function for error returns and provide a 255have to check every single BDB function for error returns and provide a
228codepath out of your transaction. While the BDB module still makes this 256codepath out of your transaction. While the BDB module still makes this
… …
254 282
255You can use the C<< $txn->failed >> method to check wether a transaction 283You can use the C<< $txn->failed >> method to check wether a transaction
256has failed in this way and abort further processing (excluding 284has failed in this way and abort further processing (excluding
257C<db_txn_finish>). 285C<db_txn_finish>).
258 286
287
259=head3 DB_ENV/database environment methods 288=head2 DB_ENV/database environment methods
260 289
261Methods available on DB_ENV/$env handles: 290Methods available on DB_ENV/$env handles:
262 291
263 DESTROY (DB_ENV_ornull *env) 292 DESTROY (DB_ENV_ornull *env)
264 CODE: 293 CODE:
… …
268 $int = $env->set_data_dir (const char *dir) 297 $int = $env->set_data_dir (const char *dir)
269 $int = $env->set_tmp_dir (const char *dir) 298 $int = $env->set_tmp_dir (const char *dir)
270 $int = $env->set_lg_dir (const char *dir) 299 $int = $env->set_lg_dir (const char *dir)
271 $int = $env->set_shm_key (long shm_key) 300 $int = $env->set_shm_key (long shm_key)
272 $int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0) 301 $int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0)
273 $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)
274 $env->set_errfile (FILE *errfile = 0) 305 $env->set_errfile (FILE *errfile = 0)
275 $env->set_msgfile (FILE *msgfile = 0) 306 $env->set_msgfile (FILE *msgfile = 0)
276 $int = $env->set_verbose (U32 which, int onoff = 1) 307 $int = $env->set_verbose (U32 which, int onoff = 1)
277 $int = $env->set_encrypt (const char *password, U32 flags = 0) 308 $int = $env->set_encrypt (const char *password, U32 flags = 0)
278 $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)
… …
290 $int = $env->mutex_set_max (U32 max) 321 $int = $env->mutex_set_max (U32 max)
291 $int = $env->mutex_set_align (U32 align) 322 $int = $env->mutex_set_align (U32 align)
292 323
293 $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)
294 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)
295 327
296=head4 Example: 328=head3 Example:
297 329
298 use AnyEvent; 330 use AnyEvent;
299 use BDB; 331 use BDB;
300 332
301 our $FH; open $FH, "<&=" . BDB::poll_fileno; 333 our $FH; open $FH, "<&=" . BDB::poll_fileno;
… …
313 0600; 345 0600;
314 346
315 $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1); 347 $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1);
316 348
317 349
318=head3 DB/database methods 350=head2 DB/database methods
319 351
320Methods available on DB/$db handles: 352Methods available on DB/$db handles:
321 353
322 DESTROY (DB_ornull *db) 354 DESTROY (DB_ornull *db)
323 CODE: 355 CODE:
… …
349 381
350 $dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0) 382 $dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0)
351 flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT 383 flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT
352 $seq = $db->sequence (U32 flags = 0) 384 $seq = $db->sequence (U32 flags = 0)
353 385
354=head4 Example: 386=head3 Example:
355 387
356 my $db = db_create $env; 388 my $db = db_create $env;
357 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;
358 390
359 for (1..1000) { 391 for (1..1000) {
… …
366 db_del $db, undef, "key $_" for 1..1000; 398 db_del $db, undef, "key $_" for 1..1000;
367 399
368 db_sync $db; 400 db_sync $db;
369 401
370 402
371=head3 DB_TXN/transaction methods 403=head2 DB_TXN/transaction methods
372 404
373Methods available on DB_TXN/$txn handles: 405Methods available on DB_TXN/$txn handles:
374 406
375 DESTROY (DB_TXN_ornull *txn) 407 DESTROY (DB_TXN_ornull *txn)
376 CODE: 408 CODE:
… …
382 414
383 $bool = $txn->failed 415 $bool = $txn->failed
384 # see db_txn_finish documentation, above 416 # see db_txn_finish documentation, above
385 417
386 418
387=head3 DBC/cursor methods 419=head2 DBC/cursor methods
388 420
389Methods available on DBC/$dbc handles: 421Methods available on DBC/$dbc handles:
390 422
391 DESTROY (DBC_ornull *dbc) 423 DESTROY (DBC_ornull *dbc)
392 CODE: 424 CODE:
393 if (dbc) 425 if (dbc)
394 dbc->c_close (dbc); 426 dbc->c_close (dbc);
395 427
396 $int = $cursor->set_priority ($priority = PRIORITY_*) 428 $int = $cursor->set_priority ($priority = PRIORITY_*) (v4.6)
397 429
398=head4 Example: 430=head3 Example:
399 431
400 my $c = $db->cursor; 432 my $c = $db->cursor;
401 433
402 for (;;) { 434 for (;;) {
403 db_c_get $c, my $key, my $data, BDB::NEXT; 435 db_c_get $c, my $key, my $data, BDB::NEXT;
… …
406 } 438 }
407 439
408 db_c_close $c; 440 db_c_close $c;
409 441
410 442
411=head3 DB_SEQUENCE/sequence methods 443=head2 DB_SEQUENCE/sequence methods
412 444
413Methods available on DB_SEQUENCE/$seq handles: 445Methods available on DB_SEQUENCE/$seq handles:
414 446
415 DESTROY (DB_SEQUENCE_ornull *seq) 447 DESTROY (DB_SEQUENCE_ornull *seq)
416 CODE: 448 CODE:
… …
421 $int = $seq->set_cachesize (U32 size) 453 $int = $seq->set_cachesize (U32 size)
422 $int = $seq->set_flags (U32 flags) 454 $int = $seq->set_flags (U32 flags)
423 flags: SEQ_DEC SEQ_INC SEQ_WRAP 455 flags: SEQ_DEC SEQ_INC SEQ_WRAP
424 $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)
425 457
426=head4 Example: 458=head3 Example:
427 459
428 my $seq = $db->sequence; 460 my $seq = $db->sequence;
429 461
430 db_sequence_open $seq, undef, "seq", BDB::CREATE; 462 db_sequence_open $seq, undef, "seq", BDB::CREATE;
431 db_sequence_get $seq, undef, 1, my $value; 463 db_sequence_get $seq, undef, 1, my $value;
432 464
433 465
434=head2 SUPPORT FUNCTIONS 466=head1 SUPPORT FUNCTIONS
435 467
436=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 468=head2 EVENT PROCESSING AND EVENT LOOP INTEGRATION
437 469
438=over 4 470=over 4
439 471
440=item $msg = BDB::strerror [$errno] 472=item $msg = BDB::strerror [$errno]
441 473
442Returns the string corresponding to the given errno value. If no argument 474Returns the string corresponding to the given errno value. If no argument
443is given, use C<$!>. 475is given, use C<$!>.
476
477Note that the BDB module also patches the C<$!> variable directly, so you
478should be able to get a bdb error string by simply stringifying C<$!>.
444 479
445=item $fileno = BDB::poll_fileno 480=item $fileno = BDB::poll_fileno
446 481
447Return the I<request result pipe file descriptor>. This filehandle must be 482Return the I<request result pipe file descriptor>. This filehandle must be
448polled for reading by some mechanism outside this module (e.g. Event or 483polled for reading by some mechanism outside this module (e.g. Event or
… …
525 BDB::poll_wait, BDB::poll_cb 560 BDB::poll_wait, BDB::poll_cb
526 while BDB::nreqs; 561 while BDB::nreqs;
527 562
528=back 563=back
529 564
565=head2 VERSION CHECKING
566
567BerkeleyDB comes in various versions, many of them have minor
568incompatibilities. This means that traditional "at least version x.x"
569checks are often not sufficient.
570
571Example: set the log_autoremove option in a way compatible with <v4.7 and
572v4.7. Note the use of & on the constants to avoid triggering a compiletime
573bug when the symbol isn't available.
574
575 $DB_ENV->set_flags (&BDB::LOG_AUTOREMOVE ) if BDB::VERSION v0, v4.7;
576 $DB_ENV->log_set_config (&BDB::LOG_AUTO_REMOVE) if BDB::VERSION v4.7;
577
578=over 4
579
580=item BDB::VERSION
581
582The C<BDB::VERSION> function, when called without arguments, returns the
583Berkeley DB version as a v-string (usually with 3 components). You should
584use C<lt> and C<ge> operators exclusively to make comparisons.
585
586Example: check for at least version 4.7.
587
588 BDB::VERSION ge v4.7 or die;
589
590=item BDB::VERSION min-version
591
592Returns true if the BDB version is at least the given version (specified
593as a v-string), false otherwise.
594
595Example: check for at least version 4.5.
596
597 BDB::VERSION v4.7 or die;
598
599=item BDB::VERSION min-version, max-version
600
601Returns true of the BDB version is at least version C<min-version> (specify C<undef> or C<v0> for any minimum version)
602and less then C<max-version>.
603
604Example: check wether version is strictly less then v4.7.
605
606 BDB::VERSION v0, v4.7
607 or die "version 4.7 is not yet supported";
608
609=back
610
611=cut
612
613sub VERSION {
614 # I was dumb enough to override the VERSION method here, so let's try
615 # to fix it up.
616
617 if ($_[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
530=head3 CONTROLLING THE NUMBER OF THREADS 631=head2 CONTROLLING THE NUMBER OF THREADS
531 632
532=over 4 633=over 4
533 634
534=item BDB::min_parallel $nthreads 635=item BDB::min_parallel $nthreads
535 636
… …
596 697
597You can still queue as many requests as you want. Therefore, 698You can still queue as many requests as you want. Therefore,
598C<max_oustsanding> is mainly useful in simple scripts (with low values) or 699C<max_oustsanding> is mainly useful in simple scripts (with low values) or
599as a stop gap to shield against fatal memory overflow (with large values). 700as a stop gap to shield against fatal memory overflow (with large values).
600 701
601=item BDB::set_sync_prepare $cb 702=item $old_cb = BDB::set_sync_prepare $cb
602 703
603Sets a callback that is called whenever a request is created without an 704Sets a callback that is called whenever a request is created without an
604explicit callback. It has to return two code references. The first is used 705explicit callback. It has to return two code references. The first is used
605as the request callback, and the second is called to wait until the first 706as the request callback (it should save the return status), and the second
606callback has been called. The default implementation works like this: 707is called to wait until the first callback has been called (it must set
708C<$!> to the return status).
709
710This mechanism can be used to include BDB into other event mechanisms,
711such as L<Coro::BDB>.
712
713To allow other, callback-based, events to be executed while callback-less
714ones are run, you could use this sync prepare function:
607 715
608 sub { 716 sub {
609 my $status; 717 my $status;
610 ( 718 (
611 sub { $status = $! }, 719 sub { $status = $! },
612 sub { BDB::poll while !defined $status; $! = $status }, 720 sub { BDB::poll while !defined $status; $! = $status },
613 ) 721 )
614 } 722 }
615 723
724It works by polling for results till the request has finished and then
725sets C<$!> to the return value. This means that if you don't use a
726callback, BDB would simply fall back to synchronous operations.
727
728By default, or if the sync prepare function is set to C<undef>, is to
729execute callback-less BDB requests in the foreground thread, setting C<$!>
730to the return value, without polling for other events.
731
616=back 732=back
617 733
618=head3 STATISTICAL INFORMATION 734=head2 STATISTICAL INFORMATION
619 735
620=over 4 736=over 4
621 737
622=item BDB::nreqs 738=item BDB::nreqs
623 739
… …
641 757
642=back 758=back
643 759
644=cut 760=cut
645 761
646set_sync_prepare { 762set_sync_prepare (undef);
647 my $status;
648 (
649 sub {
650 $status = $!;
651 },
652 sub {
653 BDB::poll while !defined $status;
654 $! = $status;
655 },
656 )
657};
658 763
659min_parallel 8; 764min_parallel 8;
660 765
661END { flush } 766END { flush }
662 767
6631; 7681;
664 769
770=head1 COMMON PITFALLS
771
772=head2 Unexpected Crashes
773
774Remember that, by default, BDB will execute requests in parallel, in
775somewhat random order. That means that it is easy to run a C<db_get>
776request on thesa me database as a concurrent C<db_close> request, leading
777to a crash, silent data corruption, eventually the next world war on
778terrorism.
779
780If you only ever use foreground requests (without a callback), this will
781not be an issue.
782
783=head2 Unexpected Freezes or Deadlocks
784
785Remember that, by default, BDB will execute requests in parallel, which
786easily leads to deadlocks (even concurrent put's on the same database can
787deadlock).
788
789You either need to run deadlock detection (and handle the resulting
790errors), or make sure only one process ever updates the database, ine one
791thread, e.g. by using only foreground requests (without a callback).
792
665=head2 FORK BEHAVIOUR 793=head1 FORK BEHAVIOUR
666 794
667This module should do "the right thing" when the process using it forks: 795This module should do "the right thing" when the process using it forks:
668 796
669Before the fork, BDB enters a quiescent state where no requests 797Before the fork, BDB enters a quiescent state where no requests
670can be added in other threads and no results will be processed. After 798can be added in other threads and no results will be processed. After
… …
680 808
681Win32 note: there is no fork on win32, and perls emulation of it is too 809Win32 note: there is no fork on win32, and perls emulation of it is too
682broken to be supported, so do not use BDB in a windows pseudo-fork, better 810broken to be supported, so do not use BDB in a windows pseudo-fork, better
683yet, switch to a more capable platform. 811yet, switch to a more capable platform.
684 812
685=head2 MEMORY USAGE 813=head1 MEMORY USAGE
686 814
687Per-request usage: 815Per-request usage:
688 816
689Each aio request uses - depending on your architecture - around 100-200 817Each aio request uses - depending on your architecture - around 100-200
690bytes of memory. In addition, stat requests need a stat buffer (possibly 818bytes of memory. In addition, stat requests need a stat buffer (possibly
… …
699 827
700In the execution phase, some aio requests require more memory for 828In the execution phase, some aio requests require more memory for
701temporary buffers, and each thread requires a stack and other data 829temporary buffers, and each thread requires a stack and other data
702structures (usually around 16k-128k, depending on the OS). 830structures (usually around 16k-128k, depending on the OS).
703 831
832=head1 WIN32 FILENAMES/DATABASE NAME MESS
833
834Perl on Win32 supports only ASCII filenames (the reason is that it abuses
835an internal flag to store wether a filename is Unicode or ANSI, but that
836flag is used for somethign else in the perl core, so there is no way to
837detect wether a filename is ANSI or Unicode-encoded). The BDB module
838tries to work around this issue by assuming that the filename is an ANSI
839filename and BDB was built for unicode support.
840
704=head1 KNOWN BUGS 841=head1 KNOWN BUGS
705 842
706Known bugs will be fixed in the next release, except: 843Known bugs will be fixed in the next release, except:
707 844
708 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
… …
710 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>,
711 above. 848 above.
712 849
713=head1 SEE ALSO 850=head1 SEE ALSO
714 851
715L<Coro::BDB>, L<IO::AIO>. 852L<AnyEvent::BDB> (event loop integration), L<Coro::BDB> (more natural
853syntax), L<IO::AIO> (nice to have).
716 854
717=head1 AUTHOR 855=head1 AUTHOR
718 856
719 Marc Lehmann <schmorp@schmorp.de> 857 Marc Lehmann <schmorp@schmorp.de>
720 http://home.schmorp.de/ 858 http://home.schmorp.de/

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