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Comparing BDB/BDB.pm (file contents):
Revision 1.34 by root, Sun Mar 30 06:17:31 2008 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:
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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 = '1.44'; 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 );
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134 136
135 require XSLoader; 137 require XSLoader;
136 XSLoader::load ("BDB", $VERSION); 138 XSLoader::load ("BDB", $VERSION);
137} 139}
138 140
139=head2 FILENAMES/DATABASE NAMES
140
141The BDB expects "binary" filenames (octet strings) for pathnames on POSIX
142systems, and "unicode" filenames (strings with characters potentially
143>255) on Win32 (expecting a Unicode win32 build - win32 is a total mess).
144
145=head2 BERKELEYDB FUNCTIONS 141=head1 BERKELEYDB FUNCTIONS
146 142
147All of these are functions. The create functions simply return a new 143All of these are functions. The create functions simply return a new
148object and never block. All the remaining functions take an optional 144object and never block. All the remaining functions take an optional
149callback as last argument. If it is missing, then the function will be 145callback as last argument. If it is missing, then the function will be
150executed synchronously. In both cases, C<$!> will reflect the return value 146executed synchronously. In both cases, C<$!> will reflect the return value
… …
154settings) are method calls on the relevant objects, so the rule of thumb 150settings) are method calls on the relevant objects, so the rule of thumb
155is: if it's a method, it's not blocking, if it's a function, it takes a 151is: if it's a method, it's not blocking, if it's a function, it takes a
156callback as last argument. 152callback as last argument.
157 153
158In the following, C<$int> signifies an integer return value, 154In the following, C<$int> signifies an integer return value,
159C<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),
160indices >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
161integer, C<NV> is a floating point value. 157floating point value.
162 158
163The 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
164values), and the C<SV *callback> is the optional callback function to call 160values).
165when the request is completed.
166 161
167The various C<DB_ENV> etc. arguments are handles return by 162The various C<DB_ENV> etc. arguments are handles return by
168C<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
169appended 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>
170for them, resulting a NULL pointer on the C level. 165for them, resulting a NULL pointer on the C level.
171 166
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
172=head3 BDB functions 190=head2 BDB functions
173 191
174Functions in the BDB namespace, exported by default: 192Functions in the BDB namespace, exported by default:
175 193
176 $env = db_env_create (U32 env_flags = 0) 194 $env = db_env_create (U32 env_flags = 0)
177 flags: RPCCLIENT 195 flags: RPCCLIENT
178 196
179 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)
180 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
181 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)
182 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)
183 flags: FORCE 201 flags: FORCE
184 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)
185 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
186 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)
187 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)
188 209
189 $db = db_create (DB_ENV *env = 0, U32 flags = 0) 210 $db = db_create (DB_ENV *env = 0, U32 flags = 0)
190 flags: XA_CREATE 211 flags: XA_CREATE
191 212
192 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)
193 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
194 db_close (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) 215 db_close (DB *db, U32 flags = 0, SV *callback = 0)
195 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)
196 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)
197 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)
198 flags: FREELIST_ONLY FREE_SPACE 220 flags: FREELIST_ONLY FREE_SPACE
199 db_sync (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) 221 db_sync (DB *db, U32 flags = 0, SV *callback = 0)
200 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)
201 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)
202 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)
203 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)
204 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
205 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)
206 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
207 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)
208 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)
209 flags: TXN_NOSYNC TXN_SYNC 232 flags: TXN_NOSYNC TXN_SYNC
210 db_txn_abort (DB_TXN *txn, SV *callback = &PL_sv_undef) 233 db_txn_abort (DB_TXN *txn, SV *callback = 0)
211 234
212 db_c_close (DBC *dbc, SV *callback = &PL_sv_undef) 235 db_c_close (DBC *dbc, SV *callback = 0)
213 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)
214 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)
215 flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA 238 flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA
216 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)
217 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
218 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)
219 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)
220 243
221 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)
222 flags: CREATE EXCL 245 flags: CREATE EXCL
223 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)
224 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)
225 flags: TXN_NOSYNC 248 flags: TXN_NOSYNC
226 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)
227 flags: TXN_NOSYNC 250 flags: TXN_NOSYNC
228 251
229=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)
230 253
231This is not actually a Berkeley DB function but a BDB module 254This is not actually a Berkeley DB function but a BDB module
232extension. The background for this exytension is: It is very annoying to 255extension. The background for this exytension is: It is very annoying to
233have 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
234codepath out of your transaction. While the BDB module still makes this 257codepath out of your transaction. While the BDB module still makes this
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260 283
261You can use the C<< $txn->failed >> method to check wether a transaction 284You can use the C<< $txn->failed >> method to check wether a transaction
262has failed in this way and abort further processing (excluding 285has failed in this way and abort further processing (excluding
263C<db_txn_finish>). 286C<db_txn_finish>).
264 287
288
265=head3 DB_ENV/database environment methods 289=head2 DB_ENV/database environment methods
266 290
267Methods available on DB_ENV/$env handles: 291Methods available on DB_ENV/$env handles:
268 292
269 DESTROY (DB_ENV_ornull *env) 293 DESTROY (DB_ENV_ornull *env)
270 CODE: 294 CODE:
… …
274 $int = $env->set_data_dir (const char *dir) 298 $int = $env->set_data_dir (const char *dir)
275 $int = $env->set_tmp_dir (const char *dir) 299 $int = $env->set_tmp_dir (const char *dir)
276 $int = $env->set_lg_dir (const char *dir) 300 $int = $env->set_lg_dir (const char *dir)
277 $int = $env->set_shm_key (long shm_key) 301 $int = $env->set_shm_key (long shm_key)
278 $int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0) 302 $int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0)
279 $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)
280 $env->set_errfile (FILE *errfile = 0) 306 $env->set_errfile (FILE *errfile = 0)
281 $env->set_msgfile (FILE *msgfile = 0) 307 $env->set_msgfile (FILE *msgfile = 0)
282 $int = $env->set_verbose (U32 which, int onoff = 1) 308 $int = $env->set_verbose (U32 which, int onoff = 1)
283 $int = $env->set_encrypt (const char *password, U32 flags = 0) 309 $int = $env->set_encrypt (const char *password, U32 flags = 0)
284 $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)
… …
296 $int = $env->mutex_set_max (U32 max) 322 $int = $env->mutex_set_max (U32 max)
297 $int = $env->mutex_set_align (U32 align) 323 $int = $env->mutex_set_align (U32 align)
298 324
299 $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)
300 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)
301 328
302=head4 Example: 329=head3 Example:
303 330
304 use AnyEvent; 331 use AnyEvent;
305 use BDB; 332 use BDB;
306 333
307 our $FH; open $FH, "<&=" . BDB::poll_fileno; 334 our $FH; open $FH, "<&=" . BDB::poll_fileno;
… …
319 0600; 346 0600;
320 347
321 $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1); 348 $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1);
322 349
323 350
324=head3 DB/database methods 351=head2 DB/database methods
325 352
326Methods available on DB/$db handles: 353Methods available on DB/$db handles:
327 354
328 DESTROY (DB_ornull *db) 355 DESTROY (DB_ornull *db)
329 CODE: 356 CODE:
… …
355 382
356 $dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0) 383 $dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0)
357 flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT 384 flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT
358 $seq = $db->sequence (U32 flags = 0) 385 $seq = $db->sequence (U32 flags = 0)
359 386
360=head4 Example: 387=head3 Example:
361 388
362 my $db = db_create $env; 389 my $db = db_create $env;
363 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;
364 391
365 for (1..1000) { 392 for (1..1000) {
… …
372 db_del $db, undef, "key $_" for 1..1000; 399 db_del $db, undef, "key $_" for 1..1000;
373 400
374 db_sync $db; 401 db_sync $db;
375 402
376 403
377=head3 DB_TXN/transaction methods 404=head2 DB_TXN/transaction methods
378 405
379Methods available on DB_TXN/$txn handles: 406Methods available on DB_TXN/$txn handles:
380 407
381 DESTROY (DB_TXN_ornull *txn) 408 DESTROY (DB_TXN_ornull *txn)
382 CODE: 409 CODE:
… …
388 415
389 $bool = $txn->failed 416 $bool = $txn->failed
390 # see db_txn_finish documentation, above 417 # see db_txn_finish documentation, above
391 418
392 419
393=head3 DBC/cursor methods 420=head2 DBC/cursor methods
394 421
395Methods available on DBC/$dbc handles: 422Methods available on DBC/$dbc handles:
396 423
397 DESTROY (DBC_ornull *dbc) 424 DESTROY (DBC_ornull *dbc)
398 CODE: 425 CODE:
399 if (dbc) 426 if (dbc)
400 dbc->c_close (dbc); 427 dbc->c_close (dbc);
401 428
402 $int = $cursor->set_priority ($priority = PRIORITY_*) 429 $int = $cursor->set_priority ($priority = PRIORITY_*) (v4.6)
403 430
404=head4 Example: 431=head3 Example:
405 432
406 my $c = $db->cursor; 433 my $c = $db->cursor;
407 434
408 for (;;) { 435 for (;;) {
409 db_c_get $c, my $key, my $data, BDB::NEXT; 436 db_c_get $c, my $key, my $data, BDB::NEXT;
… …
412 } 439 }
413 440
414 db_c_close $c; 441 db_c_close $c;
415 442
416 443
417=head3 DB_SEQUENCE/sequence methods 444=head2 DB_SEQUENCE/sequence methods
418 445
419Methods available on DB_SEQUENCE/$seq handles: 446Methods available on DB_SEQUENCE/$seq handles:
420 447
421 DESTROY (DB_SEQUENCE_ornull *seq) 448 DESTROY (DB_SEQUENCE_ornull *seq)
422 CODE: 449 CODE:
… …
427 $int = $seq->set_cachesize (U32 size) 454 $int = $seq->set_cachesize (U32 size)
428 $int = $seq->set_flags (U32 flags) 455 $int = $seq->set_flags (U32 flags)
429 flags: SEQ_DEC SEQ_INC SEQ_WRAP 456 flags: SEQ_DEC SEQ_INC SEQ_WRAP
430 $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)
431 458
432=head4 Example: 459=head3 Example:
433 460
434 my $seq = $db->sequence; 461 my $seq = $db->sequence;
435 462
436 db_sequence_open $seq, undef, "seq", BDB::CREATE; 463 db_sequence_open $seq, undef, "seq", BDB::CREATE;
437 db_sequence_get $seq, undef, 1, my $value; 464 db_sequence_get $seq, undef, 1, my $value;
438 465
439 466
440=head2 SUPPORT FUNCTIONS 467=head1 SUPPORT FUNCTIONS
441 468
442=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 469=head2 EVENT PROCESSING AND EVENT LOOP INTEGRATION
443 470
444=over 4 471=over 4
445 472
446=item $msg = BDB::strerror [$errno] 473=item $msg = BDB::strerror [$errno]
447 474
… …
534 BDB::poll_wait, BDB::poll_cb 561 BDB::poll_wait, BDB::poll_cb
535 while BDB::nreqs; 562 while BDB::nreqs;
536 563
537=back 564=back
538 565
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
539=head3 CONTROLLING THE NUMBER OF THREADS 632=head2 CONTROLLING THE NUMBER OF THREADS
540 633
541=over 4 634=over 4
542 635
543=item BDB::min_parallel $nthreads 636=item BDB::min_parallel $nthreads
544 637
… …
605 698
606You can still queue as many requests as you want. Therefore, 699You can still queue as many requests as you want. Therefore,
607C<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
608as 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).
609 702
610=item BDB::set_sync_prepare $cb 703=item $old_cb = BDB::set_sync_prepare $cb
611 704
612Sets a callback that is called whenever a request is created without an 705Sets a callback that is called whenever a request is created without an
613explicit callback. It has to return two code references. The first is used 706explicit callback. It has to return two code references. The first is used
614as the request callback, and the second is called to wait until the first 707as the request callback (it should save the return status), and the second
615callback has been called. The default implementation works like this: 708is called to wait until the first callback has been called (it must set
709C<$!> 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:
616 716
617 sub { 717 sub {
618 my $status; 718 my $status;
619 ( 719 (
620 sub { $status = $! }, 720 sub { $status = $! },
621 sub { BDB::poll while !defined $status; $! = $status }, 721 sub { BDB::poll while !defined $status; $! = $status },
622 ) 722 )
623 } 723 }
624 724
725It works by polling for results till the request has finished and then
726sets C<$!> 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
625=back 733=back
626 734
627=head3 STATISTICAL INFORMATION 735=head2 STATISTICAL INFORMATION
628 736
629=over 4 737=over 4
630 738
631=item BDB::nreqs 739=item BDB::nreqs
632 740
… …
650 758
651=back 759=back
652 760
653=cut 761=cut
654 762
655set_sync_prepare { 763set_sync_prepare (undef);
656 my $status;
657 (
658 sub {
659 $status = $!;
660 },
661 sub {
662 BDB::poll while !defined $status;
663 $! = $status;
664 },
665 )
666};
667 764
668min_parallel 8; 765min_parallel 8;
669 766
670END { flush } 767END { flush }
671 768
6721; 7691;
673 770
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
674=head2 FORK BEHAVIOUR 794=head1 FORK BEHAVIOUR
675 795
676This 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:
677 797
678Before the fork, BDB enters a quiescent state where no requests 798Before the fork, BDB enters a quiescent state where no requests
679can 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
… …
689 809
690Win32 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
691broken 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
692yet, switch to a more capable platform. 812yet, switch to a more capable platform.
693 813
694=head2 MEMORY USAGE 814=head1 MEMORY USAGE
695 815
696Per-request usage: 816Per-request usage:
697 817
698Each aio request uses - depending on your architecture - around 100-200 818Each aio request uses - depending on your architecture - around 100-200
699bytes of memory. In addition, stat requests need a stat buffer (possibly 819bytes of memory. In addition, stat requests need a stat buffer (possibly
… …
708 828
709In the execution phase, some aio requests require more memory for 829In the execution phase, some aio requests require more memory for
710temporary buffers, and each thread requires a stack and other data 830temporary buffers, and each thread requires a stack and other data
711structures (usually around 16k-128k, depending on the OS). 831structures (usually around 16k-128k, depending on the OS).
712 832
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
713=head1 KNOWN BUGS 842=head1 KNOWN BUGS
714 843
715Known bugs will be fixed in the next release, except: 844Known bugs will be fixed in the next release, except:
716 845
717 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
… …
719 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>,
720 above. 849 above.
721 850
722=head1 SEE ALSO 851=head1 SEE ALSO
723 852
724L<Coro::BDB>, L<IO::AIO>. 853L<AnyEvent::BDB> (event loop integration), L<Coro::BDB> (more natural
854syntax), L<IO::AIO> (nice to have).
725 855
726=head1 AUTHOR 856=head1 AUTHOR
727 857
728 Marc Lehmann <schmorp@schmorp.de> 858 Marc Lehmann <schmorp@schmorp.de>
729 http://home.schmorp.de/ 859 http://home.schmorp.de/

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