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Comparing BDB/BDB.pm (file contents):
Revision 1.33 by root, Sun Mar 30 04:57:55 2008 UTC vs.
Revision 1.68 by root, Tue Feb 2 04:17:03 2016 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 = '1.44'; 115 $VERSION = '1.91';
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 db_env_lsn_reset
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)
208 db_env_lsn_reset (DB_ENV *env, bdb_filename db, 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
… …
528 BDB::poll_wait, BDB::poll_cb 561 BDB::poll_wait, BDB::poll_cb
529 while BDB::nreqs; 562 while BDB::nreqs;
530 563
531=back 564=back
532 565
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
533=head3 CONTROLLING THE NUMBER OF THREADS 632=head2 CONTROLLING THE NUMBER OF THREADS
534 633
535=over 4 634=over 4
536 635
537=item BDB::min_parallel $nthreads 636=item BDB::min_parallel $nthreads
538 637
… …
599 698
600You can still queue as many requests as you want. Therefore, 699You can still queue as many requests as you want. Therefore,
601C<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
602as 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).
603 702
604=item BDB::set_sync_prepare $cb 703=item $old_cb = BDB::set_sync_prepare $cb
605 704
606Sets a callback that is called whenever a request is created without an 705Sets a callback that is called whenever a request is created without an
607explicit callback. It has to return two code references. The first is used 706explicit callback. It has to return two code references. The first is used
608as the request callback, and the second is called to wait until the first 707as the request callback (it should save the return status), and the second
609callback has been called. The default implementation works like this: 708is called to wait until the first callback has been called (it must set
709C<$!> 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:
610 716
611 sub { 717 sub {
612 my $status; 718 my $status;
613 ( 719 (
614 sub { $status = $! }, 720 sub { $status = $! },
615 sub { BDB::poll while !defined $status; $! = $status }, 721 sub { BDB::poll while !defined $status; $! = $status },
616 ) 722 )
617 } 723 }
618 724
725It works by polling for results till the request has finished and then
726sets C<$!> 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
619=back 733=back
620 734
621=head3 STATISTICAL INFORMATION 735=head2 STATISTICAL INFORMATION
622 736
623=over 4 737=over 4
624 738
625=item BDB::nreqs 739=item BDB::nreqs
626 740
… …
644 758
645=back 759=back
646 760
647=cut 761=cut
648 762
649set_sync_prepare { 763set_sync_prepare (undef);
650 my $status;
651 (
652 sub {
653 $status = $!;
654 },
655 sub {
656 BDB::poll while !defined $status;
657 $! = $status;
658 },
659 )
660};
661 764
662min_parallel 8; 765min_parallel 8;
663 766
664END { flush } 767END { flush }
665 768
6661; 7691;
667 770
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 the same 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 (unless you use threads).
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
668=head2 FORK BEHAVIOUR 794=head1 FORK BEHAVIOUR
669 795
670This 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:
671 797
672Before the fork, BDB enters a quiescent state where no requests 798Before the fork, BDB enters a quiescent state where no requests
673can 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
… …
683 809
684Win32 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
685broken 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
686yet, switch to a more capable platform. 812yet, switch to a more capable platform.
687 813
688=head2 MEMORY USAGE 814=head1 MEMORY USAGE
689 815
690Per-request usage: 816Per-request usage:
691 817
692Each aio request uses - depending on your architecture - around 100-200 818Each aio request uses - depending on your architecture - around 100-200
693bytes of memory. In addition, stat requests need a stat buffer (possibly 819bytes of memory. In addition, stat requests need a stat buffer (possibly
… …
702 828
703In the execution phase, some aio requests require more memory for 829In the execution phase, some aio requests require more memory for
704temporary buffers, and each thread requires a stack and other data 830temporary buffers, and each thread requires a stack and other data
705structures (usually around 16k-128k, depending on the OS). 831structures (usually around 16k-128k, depending on the OS).
706 832
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
707=head1 KNOWN BUGS 842=head1 KNOWN BUGS
708 843
709Known bugs will be fixed in the next release, except: 844Known bugs will be fixed in the next release, except:
710 845
711 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
… …
713 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>,
714 above. 849 above.
715 850
716=head1 SEE ALSO 851=head1 SEE ALSO
717 852
718L<Coro::BDB>, L<IO::AIO>. 853L<AnyEvent::BDB> (event loop integration), L<Coro::BDB> (more natural
854syntax), L<IO::AIO> (nice to have).
719 855
720=head1 AUTHOR 856=head1 AUTHOR
721 857
722 Marc Lehmann <schmorp@schmorp.de> 858 Marc Lehmann <schmorp@schmorp.de>
723 http://home.schmorp.de/ 859 http://home.schmorp.de/

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