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Comparing BDB/BDB.pm (file contents):
Revision 1.30 by root, Tue Dec 25 14:23:21 2007 UTC vs.
Revision 1.56 by root, Fri Jan 9 22:32:12 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 intergration 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:
… …
109no warnings; 108no warnings;
110use strict 'vars'; 109use strict 'vars';
111 110
112use base 'Exporter'; 111use base 'Exporter';
113 112
113our $VERSION;
114
114BEGIN { 115BEGIN {
115 our $VERSION = '1.42'; 116 $VERSION = '1.83';
116 117
117 our @BDB_REQ = qw( 118 our @BDB_REQ = qw(
118 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
119 db_env_memp_sync db_env_memp_trickle 120 db_env_memp_sync db_env_memp_trickle db_env_dbrename db_env_dbremove
121 db_env_log_archive
120 db_open db_close db_compact db_sync db_upgrade 122 db_open db_close db_compact db_sync db_verify db_upgrade
121 db_put db_get db_pget db_del db_key_range 123 db_put db_exists db_get db_pget db_del db_key_range
122 db_txn_commit db_txn_abort db_txn_finish 124 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 125 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 126 db_sequence_open db_sequence_close
125 db_sequence_get db_sequence_remove 127 db_sequence_get db_sequence_remove
126 ); 128 );
… …
134 136
135 require XSLoader; 137 require XSLoader;
136 XSLoader::load ("BDB", $VERSION); 138 XSLoader::load ("BDB", $VERSION);
137} 139}
138 140
139=head2 BERKELEYDB FUNCTIONS 141=head1 BERKELEYDB FUNCTIONS
140 142
141All of these are functions. The create functions simply return a new 143All of these are functions. The create functions simply return a new
142object and never block. All the remaining functions all take an optional 144object and never block. All the remaining functions take an optional
143callback as last argument. If it is missing, then the function will be 145callback as last argument. If it is missing, then the function will be
144executed synchronously. In both cases, C<$!> will reflect the return value 146executed synchronously. In both cases, C<$!> will reflect the return value
145of the function. 147of the function.
146 148
147BDB functions that cannot block (mostly functions that manipulate 149BDB functions that cannot block (mostly functions that manipulate
148settings) are method calls on the relevant objects, so the rule of thumb 150settings) are method calls on the relevant objects, so the rule of thumb
149is: if its a method, its not blocking, if its a function, it takes a 151is: if it's a method, it's not blocking, if it's a function, it takes a
150callback as last argument. 152callback as last argument.
151 153
152In the following, C<$int> signifies an integer return value, 154In the following, C<$int> signifies an integer return value,
153C<octetstring> is a "binary string" (i.e. a perl string with no character 155C<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 156C<U32> is an unsigned 32 bit integer, C<int> is some integer, C<NV> is a
155integer, C<NV> is a floating point value. 157floating point value.
156 158
157The C<SV *> types are generic perl scalars (for input and output of data 159Most 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 160values).
159when the request is completed.
160 161
161The various C<DB_ENV> etc. arguments are handles return by 162The 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 163C<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> 164appended C<_ornull> this means they are optional and you can pass C<undef>
164for them, resulting a NULL pointer on the C level. 165for them, resulting a NULL pointer on the C level.
165 166
167The C<SV *callback> is the optional callback function to call when the
168request is completed. This last callback argument is special: the callback
169is simply the last argument passed. If there are "optional" arguments
170before the callback they can be left out. The callback itself can be left
171out or specified as C<undef>, in which case the function will be executed
172synchronously.
173
174For example, C<db_env_txn_checkpoint> usually is called with all integer
175arguments zero. These can be left out, so all of these specify a call
176to C<< DB_ENV->txn_checkpoint >>, to be executed asynchronously with a
177callback 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
183While these all specify a call to C<< DB_ENV->txn_checkpoint >> to be
184executed 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
166=head3 BDB functions 190=head2 BDB functions
167 191
168Functions in the BDB namespace, exported by default: 192Functions in the BDB namespace, exported by default:
169 193
170 $env = db_env_create (U32 env_flags = 0) 194 $env = db_env_create (U32 env_flags = 0)
171 flags: RPCCLIENT 195 flags: RPCCLIENT
172 196
173 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 = 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 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
175 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 = 0)
176 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 = 0)
177 flags: FORCE 201 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) 202 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 203 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) 204 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) 205 db_env_memp_trickle (DB_ENV *env, int percent, SV *dummy = 0, SV *callback = 0)
206 db_env_dbremove (DB_ENV *env, DB_TXN_ornull *txnid, bdb_filename file, bdb_filename database, U32 flags = 0, SV *callback = 0)
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 = 0)
208 db_env_log_archive (DB_ENV *env, SV *listp, U32 flags = 0, SV *callback = 0)
182 209
183 $db = db_create (DB_ENV *env = 0, U32 flags = 0) 210 $db = db_create (DB_ENV *env = 0, U32 flags = 0)
184 flags: XA_CREATE 211 flags: XA_CREATE
185 212
186 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 = 0)
187 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
188 db_close (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) 215 db_close (DB *db, U32 flags = 0, SV *callback = 0)
189 flags: DB_NOSYNC 216 flags: DB_NOSYNC
217 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) 218 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) 219 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 220 flags: FREELIST_ONLY FREE_SPACE
193 db_sync (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) 221 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) 222 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) 223 db_put (DB *db, DB_TXN_ornull *txn, SV *key, SV *data, U32 flags = 0, SV *callback = 0)
196 flags: APPEND NODUPDATA NOOVERWRITE 224 flags: APPEND NODUPDATA NOOVERWRITE
225 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) 226 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 227 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) 228 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 229 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) 230 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) 231 db_txn_commit (DB_TXN *txn, U32 flags = 0, SV *callback = 0)
203 flags: TXN_NOSYNC TXN_SYNC 232 flags: TXN_NOSYNC TXN_SYNC
204 db_txn_abort (DB_TXN *txn, SV *callback = &PL_sv_undef) 233 db_txn_abort (DB_TXN *txn, SV *callback = 0)
205 234
206 db_c_close (DBC *dbc, SV *callback = &PL_sv_undef) 235 db_c_close (DBC *dbc, SV *callback = 0)
207 db_c_count (DBC *dbc, SV *count, U32 flags = 0, SV *callback = &PL_sv_undef) 236 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) 237 db_c_put (DBC *dbc, SV *key, SV *data, U32 flags = 0, SV *callback = 0)
209 flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA 238 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) 239 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 240 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) 241 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) 242 db_c_del (DBC *dbc, U32 flags = 0, SV *callback = 0)
214 243
215 db_sequence_open (DB_SEQUENCE *seq, DB_TXN_ornull *txnid, SV *key, U32 flags = 0, SV *callback = &PL_sv_undef) 244 db_sequence_open (DB_SEQUENCE *seq, DB_TXN_ornull *txnid, SV *key, U32 flags = 0, SV *callback = 0)
216 flags: CREATE EXCL 245 flags: CREATE EXCL
217 db_sequence_close (DB_SEQUENCE *seq, U32 flags = 0, SV *callback = &PL_sv_undef) 246 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) 247 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 248 flags: TXN_NOSYNC
220 db_sequence_remove (DB_SEQUENCE *seq, DB_TXN_ornull *txnid = 0, U32 flags = 0, SV *callback = &PL_sv_undef) 249 db_sequence_remove (DB_SEQUENCE *seq, DB_TXN_ornull *txnid = 0, U32 flags = 0, SV *callback = 0)
221 flags: TXN_NOSYNC 250 flags: TXN_NOSYNC
222 251
223=head4 db_txn_finish (DB_TXN *txn, U32 flags = 0, SV *callback = &PL_sv_undef) 252=head3 db_txn_finish (DB_TXN *txn, U32 flags = 0, SV *callback = 0)
224 253
225This is not actually a Berkeley DB function but a BDB module 254This is not actually a Berkeley DB function but a BDB module
226extension. The background for this exytension is: It is very annoying to 255extension. The background for this exytension is: It is very annoying to
227have to check every single BDB function for error returns and provide a 256have to check every single BDB function for error returns and provide a
228codepath out of your transaction. While the BDB module still makes this 257codepath out of your transaction. While the BDB module still makes this
… …
254 283
255You can use the C<< $txn->failed >> method to check wether a transaction 284You can use the C<< $txn->failed >> method to check wether a transaction
256has failed in this way and abort further processing (excluding 285has failed in this way and abort further processing (excluding
257C<db_txn_finish>). 286C<db_txn_finish>).
258 287
288
259=head3 DB_ENV/database environment methods 289=head2 DB_ENV/database environment methods
260 290
261Methods available on DB_ENV/$env handles: 291Methods available on DB_ENV/$env handles:
262 292
263 DESTROY (DB_ENV_ornull *env) 293 DESTROY (DB_ENV_ornull *env)
264 CODE: 294 CODE:
… …
268 $int = $env->set_data_dir (const char *dir) 298 $int = $env->set_data_dir (const char *dir)
269 $int = $env->set_tmp_dir (const char *dir) 299 $int = $env->set_tmp_dir (const char *dir)
270 $int = $env->set_lg_dir (const char *dir) 300 $int = $env->set_lg_dir (const char *dir)
271 $int = $env->set_shm_key (long shm_key) 301 $int = $env->set_shm_key (long shm_key)
272 $int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0) 302 $int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0)
273 $int = $env->set_flags (U32 flags, int onoff) 303 $int = $env->set_flags (U32 flags, int onoff = 1)
304 $int = $env->log_set_config (U32 flags, int onoff = 1) (v4.7)
305 $int = $env->set_intermediate_dir_mode (const char *modestring) (v4.7)
274 $env->set_errfile (FILE *errfile = 0) 306 $env->set_errfile (FILE *errfile = 0)
275 $env->set_msgfile (FILE *msgfile = 0) 307 $env->set_msgfile (FILE *msgfile = 0)
276 $int = $env->set_verbose (U32 which, int onoff = 1) 308 $int = $env->set_verbose (U32 which, int onoff = 1)
277 $int = $env->set_encrypt (const char *password, U32 flags = 0) 309 $int = $env->set_encrypt (const char *password, U32 flags = 0)
278 $int = $env->set_timeout (NV timeout_seconds, U32 flags = SET_TXN_TIMEOUT) 310 $int = $env->set_timeout (NV timeout_seconds, U32 flags = SET_TXN_TIMEOUT)
… …
290 $int = $env->mutex_set_max (U32 max) 322 $int = $env->mutex_set_max (U32 max)
291 $int = $env->mutex_set_align (U32 align) 323 $int = $env->mutex_set_align (U32 align)
292 324
293 $txn = $env->txn_begin (DB_TXN_ornull *parent = 0, U32 flags = 0) 325 $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 326 flags: READ_COMMITTED READ_UNCOMMITTED TXN_NOSYNC TXN_NOWAIT TXN_SNAPSHOT TXN_SYNC TXN_WAIT TXN_WRITE_NOSYNC
327 $txn = $env->cdsgroup_begin; (v4.5)
295 328
296=head4 Example: 329=head3 Example:
297 330
298 use AnyEvent; 331 use AnyEvent;
299 use BDB; 332 use BDB;
300 333
301 our $FH; open $FH, "<&=" . BDB::poll_fileno; 334 our $FH; open $FH, "<&=" . BDB::poll_fileno;
… …
313 0600; 346 0600;
314 347
315 $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1); 348 $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1);
316 349
317 350
318=head3 DB/database methods 351=head2 DB/database methods
319 352
320Methods available on DB/$db handles: 353Methods available on DB/$db handles:
321 354
322 DESTROY (DB_ornull *db) 355 DESTROY (DB_ornull *db)
323 CODE: 356 CODE:
… …
349 382
350 $dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0) 383 $dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0)
351 flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT 384 flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT
352 $seq = $db->sequence (U32 flags = 0) 385 $seq = $db->sequence (U32 flags = 0)
353 386
354=head4 Example: 387=head3 Example:
355 388
356 my $db = db_create $env; 389 my $db = db_create $env;
357 db_open $db, undef, "table", undef, BDB::BTREE, BDB::AUTO_COMMIT | BDB::CREATE | BDB::READ_UNCOMMITTED, 0600; 390 db_open $db, undef, "table", undef, BDB::BTREE, BDB::AUTO_COMMIT | BDB::CREATE | BDB::READ_UNCOMMITTED, 0600;
358 391
359 for (1..1000) { 392 for (1..1000) {
… …
366 db_del $db, undef, "key $_" for 1..1000; 399 db_del $db, undef, "key $_" for 1..1000;
367 400
368 db_sync $db; 401 db_sync $db;
369 402
370 403
371=head3 DB_TXN/transaction methods 404=head2 DB_TXN/transaction methods
372 405
373Methods available on DB_TXN/$txn handles: 406Methods available on DB_TXN/$txn handles:
374 407
375 DESTROY (DB_TXN_ornull *txn) 408 DESTROY (DB_TXN_ornull *txn)
376 CODE: 409 CODE:
… …
382 415
383 $bool = $txn->failed 416 $bool = $txn->failed
384 # see db_txn_finish documentation, above 417 # see db_txn_finish documentation, above
385 418
386 419
387=head3 DBC/cursor methods 420=head2 DBC/cursor methods
388 421
389Methods available on DBC/$dbc handles: 422Methods available on DBC/$dbc handles:
390 423
391 DESTROY (DBC_ornull *dbc) 424 DESTROY (DBC_ornull *dbc)
392 CODE: 425 CODE:
393 if (dbc) 426 if (dbc)
394 dbc->c_close (dbc); 427 dbc->c_close (dbc);
395 428
396 $int = $cursor->set_priority ($priority = PRIORITY_*) 429 $int = $cursor->set_priority ($priority = PRIORITY_*) (v4.6)
397 430
398=head4 Example: 431=head3 Example:
399 432
400 my $c = $db->cursor; 433 my $c = $db->cursor;
401 434
402 for (;;) { 435 for (;;) {
403 db_c_get $c, my $key, my $data, BDB::NEXT; 436 db_c_get $c, my $key, my $data, BDB::NEXT;
… …
406 } 439 }
407 440
408 db_c_close $c; 441 db_c_close $c;
409 442
410 443
411=head3 DB_SEQUENCE/sequence methods 444=head2 DB_SEQUENCE/sequence methods
412 445
413Methods available on DB_SEQUENCE/$seq handles: 446Methods available on DB_SEQUENCE/$seq handles:
414 447
415 DESTROY (DB_SEQUENCE_ornull *seq) 448 DESTROY (DB_SEQUENCE_ornull *seq)
416 CODE: 449 CODE:
… …
421 $int = $seq->set_cachesize (U32 size) 454 $int = $seq->set_cachesize (U32 size)
422 $int = $seq->set_flags (U32 flags) 455 $int = $seq->set_flags (U32 flags)
423 flags: SEQ_DEC SEQ_INC SEQ_WRAP 456 flags: SEQ_DEC SEQ_INC SEQ_WRAP
424 $int = $seq->set_range (db_seq_t min, db_seq_t max) 457 $int = $seq->set_range (db_seq_t min, db_seq_t max)
425 458
426=head4 Example: 459=head3 Example:
427 460
428 my $seq = $db->sequence; 461 my $seq = $db->sequence;
429 462
430 db_sequence_open $seq, undef, "seq", BDB::CREATE; 463 db_sequence_open $seq, undef, "seq", BDB::CREATE;
431 db_sequence_get $seq, undef, 1, my $value; 464 db_sequence_get $seq, undef, 1, my $value;
432 465
433 466
434=head2 SUPPORT FUNCTIONS 467=head1 SUPPORT FUNCTIONS
435 468
436=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 469=head2 EVENT PROCESSING AND EVENT LOOP INTEGRATION
437 470
438=over 4 471=over 4
439 472
440=item $msg = BDB::strerror [$errno] 473=item $msg = BDB::strerror [$errno]
441 474
442Returns the string corresponding to the given errno value. If no argument 475Returns the string corresponding to the given errno value. If no argument
443is given, use C<$!>. 476is given, use C<$!>.
477
478Note that the BDB module also patches the C<$!> variable directly, so you
479should be able to get a bdb error string by simply stringifying C<$!>.
444 480
445=item $fileno = BDB::poll_fileno 481=item $fileno = BDB::poll_fileno
446 482
447Return the I<request result pipe file descriptor>. This filehandle must be 483Return the I<request result pipe file descriptor>. This filehandle must be
448polled for reading by some mechanism outside this module (e.g. Event or 484polled for reading by some mechanism outside this module (e.g. Event or
… …
525 BDB::poll_wait, BDB::poll_cb 561 BDB::poll_wait, BDB::poll_cb
526 while BDB::nreqs; 562 while BDB::nreqs;
527 563
528=back 564=back
529 565
566=head2 VERSION CHECKING
567
568BerkeleyDB comes in various versions, many of them have minor
569incompatibilities. This means that traditional "at least version x.x"
570checks are often not sufficient.
571
572Example: set the log_autoremove option in a way compatible with <v4.7 and
573v4.7. Note the use of & on the constants to avoid triggering a compiletime
574bug when the symbol isn't available.
575
576 $DB_ENV->set_flags (&BDB::LOG_AUTOREMOVE ) if BDB::VERSION v0, v4.7;
577 $DB_ENV->log_set_config (&BDB::LOG_AUTO_REMOVE) if BDB::VERSION v4.7;
578
579=over 4
580
581=item BDB::VERSION
582
583The C<BDB::VERSION> function, when called without arguments, returns the
584Berkeley DB version as a v-string (usually with 3 components). You should
585use C<lt> and C<ge> operators exclusively to make comparisons.
586
587Example: check for at least version 4.7.
588
589 BDB::VERSION ge v4.7 or die;
590
591=item BDB::VERSION min-version
592
593Returns true if the BDB version is at least the given version (specified
594as a v-string), false otherwise.
595
596Example: check for at least version 4.5.
597
598 BDB::VERSION v4.7 or die;
599
600=item BDB::VERSION min-version, max-version
601
602Returns true of the BDB version is at least version C<min-version> (specify C<undef> or C<v0> for any minimum version)
603and less then C<max-version>.
604
605Example: check wether version is strictly less then v4.7.
606
607 BDB::VERSION v0, v4.7
608 or die "version 4.7 is not yet supported";
609
610=back
611
612=cut
613
614sub VERSION {
615 # I was dumb enough to override the VERSION method here, so let's try
616 # to fix it up.
617
618 if ($_[0] eq __PACKAGE__) {
619 $VERSION
620 } else {
621 if (@_ > 0) {
622 return undef if VERSION_v lt $_[0];
623 if (@_ > 1) {
624 return undef if VERSION_v ge $_[1];
625 }
626 }
627
628 VERSION_v
629 }
630}
631
530=head3 CONTROLLING THE NUMBER OF THREADS 632=head2 CONTROLLING THE NUMBER OF THREADS
531 633
532=over 4 634=over 4
533 635
534=item BDB::min_parallel $nthreads 636=item BDB::min_parallel $nthreads
535 637
… …
596 698
597You can still queue as many requests as you want. Therefore, 699You can still queue as many requests as you want. Therefore,
598C<max_oustsanding> is mainly useful in simple scripts (with low values) or 700C<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). 701as a stop gap to shield against fatal memory overflow (with large values).
600 702
601=item BDB::set_sync_prepare $cb 703=item $old_cb = BDB::set_sync_prepare $cb
602 704
603Sets a callback that is called whenever a request is created without an 705Sets a callback that is called whenever a request is created without an
604explicit callback. It has to return two code references. The first is used 706explicit callback. It has to return two code references. The first is used
605as the request callback, and the second is called to wait until the first 707as the request callback (it should save the return status), and the second
606callback has been called. The default implementation works like this: 708is called to wait until the first callback has been called (it must set
709C<$!> to the return status).
710
711This mechanism can be used to include BDB into other event mechanisms,
712such as L<Coro::BDB>.
713
714To allow other, callback-based, events to be executed while callback-less
715ones are run, you could use this sync prepare function:
607 716
608 sub { 717 sub {
609 my $status; 718 my $status;
610 ( 719 (
611 sub { $status = $! }, 720 sub { $status = $! },
612 sub { BDB::poll while !defined $status; $! = $status }, 721 sub { BDB::poll while !defined $status; $! = $status },
613 ) 722 )
614 } 723 }
615 724
725It works by polling for results till the request has finished and then
726sets C<$!> to the return value. This means that if you don't use a
727callback, BDB would simply fall back to synchronous operations.
728
729By default, or if the sync prepare function is set to C<undef>, is to
730execute callback-less BDB requests in the foreground thread, setting C<$!>
731to the return value, without polling for other events.
732
616=back 733=back
617 734
618=head3 STATISTICAL INFORMATION 735=head2 STATISTICAL INFORMATION
619 736
620=over 4 737=over 4
621 738
622=item BDB::nreqs 739=item BDB::nreqs
623 740
… …
641 758
642=back 759=back
643 760
644=cut 761=cut
645 762
646set_sync_prepare { 763set_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};
658 764
659min_parallel 8; 765min_parallel 8;
660 766
661END { flush } 767END { flush }
662 768
6631; 7691;
664 770
771=head1 COMMON PITFALLS
772
773=head2 Unexpected Crashes
774
775Remember that, by default, BDB will execute requests in parallel, in
776somewhat random order. That means that it is easy to run a C<db_get>
777request on thesa me database as a concurrent C<db_close> request, leading
778to a crash, silent data corruption, eventually the next world war on
779terrorism.
780
781If you only ever use foreground requests (without a callback), this will
782not be an issue.
783
784=head2 Unexpected Freezes or Deadlocks
785
786Remember that, by default, BDB will execute requests in parallel, which
787easily leads to deadlocks (even concurrent put's on the same database can
788deadlock).
789
790You either need to run deadlock detection (and handle the resulting
791errors), or make sure only one process ever updates the database, ine one
792thread, e.g. by using only foreground requests (without a callback).
793
665=head2 FORK BEHAVIOUR 794=head1 FORK BEHAVIOUR
666 795
667This module should do "the right thing" when the process using it forks: 796This module should do "the right thing" when the process using it forks:
668 797
669Before the fork, BDB enters a quiescent state where no requests 798Before the fork, BDB enters a quiescent state where no requests
670can be added in other threads and no results will be processed. After 799can be added in other threads and no results will be processed. After
… …
680 809
681Win32 note: there is no fork on win32, and perls emulation of it is too 810Win32 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 811broken to be supported, so do not use BDB in a windows pseudo-fork, better
683yet, switch to a more capable platform. 812yet, switch to a more capable platform.
684 813
685=head2 MEMORY USAGE 814=head1 MEMORY USAGE
686 815
687Per-request usage: 816Per-request usage:
688 817
689Each aio request uses - depending on your architecture - around 100-200 818Each aio request uses - depending on your architecture - around 100-200
690bytes of memory. In addition, stat requests need a stat buffer (possibly 819bytes of memory. In addition, stat requests need a stat buffer (possibly
… …
699 828
700In the execution phase, some aio requests require more memory for 829In the execution phase, some aio requests require more memory for
701temporary buffers, and each thread requires a stack and other data 830temporary buffers, and each thread requires a stack and other data
702structures (usually around 16k-128k, depending on the OS). 831structures (usually around 16k-128k, depending on the OS).
703 832
833=head1 WIN32 FILENAMES/DATABASE NAME MESS
834
835Perl on Win32 supports only ASCII filenames (the reason is that it abuses
836an internal flag to store wether a filename is Unicode or ANSI, but that
837flag is used for somethign else in the perl core, so there is no way to
838detect wether a filename is ANSI or Unicode-encoded). The BDB module
839tries to work around this issue by assuming that the filename is an ANSI
840filename and BDB was built for unicode support.
841
704=head1 KNOWN BUGS 842=head1 KNOWN BUGS
705 843
706Known bugs will be fixed in the next release, except: 844Known bugs will be fixed in the next release, except:
707 845
708 If you use a transaction in any request, and the request returns 846 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>, 848 TXN_DEADLOCK flag will be set on the transaction. See C<db_txn_finish>,
711 above. 849 above.
712 850
713=head1 SEE ALSO 851=head1 SEE ALSO
714 852
715L<Coro::BDB>, L<IO::AIO>. 853L<AnyEvent::BDB> (event loop integration), L<Coro::BDB> (more natural
854syntax), L<IO::AIO> (nice to have).
716 855
717=head1 AUTHOR 856=head1 AUTHOR
718 857
719 Marc Lehmann <schmorp@schmorp.de> 858 Marc Lehmann <schmorp@schmorp.de>
720 http://home.schmorp.de/ 859 http://home.schmorp.de/

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