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Comparing BDB/BDB.pm (file contents):
Revision 1.39 by root, Tue Jul 8 08:25:31 2008 UTC vs.
Revision 1.63 by root, Fri Jul 29 09:30:19 2011 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 event loop intergration with AnyEvent: 32 # automatic event loop integration with AnyEvent:
33 use AnyEvent::BDB; 33 use AnyEvent::BDB;
34 34
35 # automatic result processing with EV: 35 # automatic result processing with EV:
36 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;
37 37
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103 103
104=cut 104=cut
105 105
106package BDB; 106package BDB;
107 107
108no warnings; 108use common::sense;
109use strict 'vars';
110 109
111use base 'Exporter'; 110use base 'Exporter';
112 111
112our $VERSION;
113
113BEGIN { 114BEGIN {
114 our $VERSION = '1.6'; 115 $VERSION = '1.89';
115 116
116 our @BDB_REQ = qw( 117 our @BDB_REQ = qw(
117 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
118 db_env_memp_sync db_env_memp_trickle db_env_dbrename db_env_dbremove 119 db_env_memp_sync db_env_memp_trickle db_env_dbrename db_env_dbremove
120 db_env_log_archive
119 db_open db_close db_compact db_sync db_upgrade 121 db_open db_close db_compact db_sync db_verify db_upgrade
120 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
121 db_txn_commit db_txn_abort db_txn_finish 123 db_txn_commit db_txn_abort db_txn_finish
122 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
123 db_sequence_open db_sequence_close 125 db_sequence_open db_sequence_close
124 db_sequence_get db_sequence_remove 126 db_sequence_get db_sequence_remove
125 ); 127 );
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133 135
134 require XSLoader; 136 require XSLoader;
135 XSLoader::load ("BDB", $VERSION); 137 XSLoader::load ("BDB", $VERSION);
136} 138}
137 139
138=head2 WIN32 FILENAMES/DATABASE NAME MESS
139
140Perl on Win32 supports only ASCII filenames (the reason is that it abuses
141an internal flag to store wether a filename is Unicode or ANSI, but that
142flag is used for somethign else in the perl core, so there is no way to
143detect wether a filename is ANSI or Unicode-encoded). The BDB module
144tries to work around this issue by assuming that the filename is an ANSI
145filename and BDB was built for unicode support.
146
147=head2 BERKELEYDB FUNCTIONS 140=head1 BERKELEYDB FUNCTIONS
148 141
149All of these are functions. The create functions simply return a new 142All of these are functions. The create functions simply return a new
150object and never block. All the remaining functions take an optional 143object and never block. All the remaining functions take an optional
151callback as last argument. If it is missing, then the function will be 144callback as last argument. If it is missing, then the function will be
152executed synchronously. In both cases, C<$!> will reflect the return value 145executed synchronously. In both cases, C<$!> will reflect the return value
… …
160In the following, C<$int> signifies an integer return value, 153In the following, C<$int> signifies an integer return value,
161C<bdb_filename> is a "filename" (octets on unix, madness on windows), 154C<bdb_filename> is a "filename" (octets on unix, madness on windows),
162C<U32> is an unsigned 32 bit integer, C<int> is some integer, C<NV> is a 155C<U32> is an unsigned 32 bit integer, C<int> is some integer, C<NV> is a
163floating point value. 156floating point value.
164 157
165The 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
166values), and the C<SV *callback> is the optional callback function to call 159values).
167when the request is completed.
168 160
169The various C<DB_ENV> etc. arguments are handles return by 161The various C<DB_ENV> etc. arguments are handles return by
170C<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
171appended 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>
172for them, resulting a NULL pointer on the C level. 164for them, resulting a NULL pointer on the C level.
173 165
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
174=head3 BDB functions 189=head2 BDB functions
175 190
176Functions in the BDB namespace, exported by default: 191Functions in the BDB namespace, exported by default:
177 192
178 $env = db_env_create (U32 env_flags = 0) 193 $env = db_env_create (U32 env_flags = 0)
179 flags: RPCCLIENT 194 flags: RPCCLIENT
180 195
181 db_env_open (DB_ENV *env, bdb_filename 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)
182 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
183 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)
184 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)
185 flags: FORCE 200 flags: FORCE
186 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)
187 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
188 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)
189 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)
190 db_env_dbremove (DB_ENV *env, DB_TXN_ornull *txnid, bdb_filename file, bdb_filename database, U32 flags = 0, SV *callback = &PL_sv_undef) 205 db_env_dbremove (DB_ENV *env, DB_TXN_ornull *txnid, bdb_filename file, bdb_filename database, U32 flags = 0, SV *callback = 0)
191 db_env_dbrename (DB_ENV *env, DB_TXN_ornull *txnid, bdb_filename file, bdb_filename database, bdb_filename newname, U32 flags = 0, SV *callback = &PL_sv_undef) 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)
192 208
193 $db = db_create (DB_ENV *env = 0, U32 flags = 0) 209 $db = db_create (DB_ENV *env = 0, U32 flags = 0)
194 flags: XA_CREATE 210 flags: XA_CREATE
195 211
196 db_open (DB *db, DB_TXN_ornull *txnid, bdb_filename file, bdb_filename database, int type, U32 flags, int mode, SV *callback = &PL_sv_undef) 212 db_open (DB *db, DB_TXN_ornull *txnid, bdb_filename file, bdb_filename database, int type, U32 flags, int mode, SV *callback = 0)
197 flags: AUTO_COMMIT CREATE EXCL MULTIVERSION NOMMAP RDONLY READ_UNCOMMITTED THREAD TRUNCATE 213 flags: AUTO_COMMIT CREATE EXCL MULTIVERSION NOMMAP RDONLY READ_UNCOMMITTED THREAD TRUNCATE
198 db_close (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) 214 db_close (DB *db, U32 flags = 0, SV *callback = 0)
199 flags: DB_NOSYNC 215 flags: DB_NOSYNC
216 db_verify (DB *db, bdb_filename file, bdb_filename database = 0, SV *dummy = 0, U32 flags = 0, SV *callback = 0)
200 db_upgrade (DB *db, bdb_filename file, U32 flags = 0, SV *callback = &PL_sv_undef) 217 db_upgrade (DB *db, bdb_filename file, U32 flags = 0, SV *callback = 0)
201 db_compact (DB *db, DB_TXN_ornull *txn = 0, SV *start = 0, SV *stop = 0, SV *unused1 = 0, U32 flags = DB_FREE_SPACE, SV *unused2 = 0, SV *callback = &PL_sv_undef) 218 db_compact (DB *db, DB_TXN_ornull *txn = 0, SV *start = 0, SV *stop = 0, SV *unused1 = 0, U32 flags = DB_FREE_SPACE, SV *unused2 = 0, SV *callback = 0)
202 flags: FREELIST_ONLY FREE_SPACE 219 flags: FREELIST_ONLY FREE_SPACE
203 db_sync (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) 220 db_sync (DB *db, U32 flags = 0, SV *callback = 0)
204 db_key_range (DB *db, DB_TXN_ornull *txn, SV *key, SV *key_range, U32 flags = 0, SV *callback = &PL_sv_undef) 221 db_key_range (DB *db, DB_TXN_ornull *txn, SV *key, SV *key_range, U32 flags = 0, SV *callback = 0)
205 db_put (DB *db, DB_TXN_ornull *txn, SV *key, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) 222 db_put (DB *db, DB_TXN_ornull *txn, SV *key, SV *data, U32 flags = 0, SV *callback = 0)
206 flags: APPEND NODUPDATA NOOVERWRITE 223 flags: APPEND NODUPDATA NOOVERWRITE
224 db_exists (DB *db, DB_TXN_ornull *txn, SV *key, U32 flags = 0, SV *callback = 0) (v4.6)
207 db_get (DB *db, DB_TXN_ornull *txn, SV *key, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) 225 db_get (DB *db, DB_TXN_ornull *txn, SV *key, SV *data, U32 flags = 0, SV *callback = 0)
208 flags: CONSUME CONSUME_WAIT GET_BOTH SET_RECNO MULTIPLE READ_COMMITTED READ_UNCOMMITTED RMW 226 flags: CONSUME CONSUME_WAIT GET_BOTH SET_RECNO MULTIPLE READ_COMMITTED READ_UNCOMMITTED RMW
209 db_pget (DB *db, DB_TXN_ornull *txn, SV *key, SV *pkey, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) 227 db_pget (DB *db, DB_TXN_ornull *txn, SV *key, SV *pkey, SV *data, U32 flags = 0, SV *callback = 0)
210 flags: CONSUME CONSUME_WAIT GET_BOTH SET_RECNO MULTIPLE READ_COMMITTED READ_UNCOMMITTED RMW 228 flags: CONSUME CONSUME_WAIT GET_BOTH SET_RECNO MULTIPLE READ_COMMITTED READ_UNCOMMITTED RMW
211 db_del (DB *db, DB_TXN_ornull *txn, SV *key, U32 flags = 0, SV *callback = &PL_sv_undef) 229 db_del (DB *db, DB_TXN_ornull *txn, SV *key, U32 flags = 0, SV *callback = 0)
212 db_txn_commit (DB_TXN *txn, U32 flags = 0, SV *callback = &PL_sv_undef) 230 db_txn_commit (DB_TXN *txn, U32 flags = 0, SV *callback = 0)
213 flags: TXN_NOSYNC TXN_SYNC 231 flags: TXN_NOSYNC TXN_SYNC
214 db_txn_abort (DB_TXN *txn, SV *callback = &PL_sv_undef) 232 db_txn_abort (DB_TXN *txn, SV *callback = 0)
215 233
216 db_c_close (DBC *dbc, SV *callback = &PL_sv_undef) 234 db_c_close (DBC *dbc, SV *callback = 0)
217 db_c_count (DBC *dbc, SV *count, U32 flags = 0, SV *callback = &PL_sv_undef) 235 db_c_count (DBC *dbc, SV *count, U32 flags = 0, SV *callback = 0)
218 db_c_put (DBC *dbc, SV *key, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) 236 db_c_put (DBC *dbc, SV *key, SV *data, U32 flags = 0, SV *callback = 0)
219 flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA 237 flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA
220 db_c_get (DBC *dbc, SV *key, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) 238 db_c_get (DBC *dbc, SV *key, SV *data, U32 flags = 0, SV *callback = 0)
221 flags: CURRENT FIRST GET_BOTH GET_BOTH_RANGE GET_RECNO JOIN_ITEM LAST NEXT NEXT_DUP NEXT_NODUP PREV PREV_DUP PREV_NODUP SET SET_RANGE SET_RECNO READ_UNCOMMITTED MULTIPLE MULTIPLE_KEY RMW 239 flags: CURRENT FIRST GET_BOTH GET_BOTH_RANGE GET_RECNO JOIN_ITEM LAST NEXT NEXT_DUP NEXT_NODUP PREV PREV_DUP PREV_NODUP SET SET_RANGE SET_RECNO READ_UNCOMMITTED MULTIPLE MULTIPLE_KEY RMW
222 db_c_pget (DBC *dbc, SV *key, SV *pkey, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) 240 db_c_pget (DBC *dbc, SV *key, SV *pkey, SV *data, U32 flags = 0, SV *callback = 0)
223 db_c_del (DBC *dbc, U32 flags = 0, SV *callback = &PL_sv_undef) 241 db_c_del (DBC *dbc, U32 flags = 0, SV *callback = 0)
224 242
225 db_sequence_open (DB_SEQUENCE *seq, DB_TXN_ornull *txnid, SV *key, U32 flags = 0, SV *callback = &PL_sv_undef) 243 db_sequence_open (DB_SEQUENCE *seq, DB_TXN_ornull *txnid, SV *key, U32 flags = 0, SV *callback = 0)
226 flags: CREATE EXCL 244 flags: CREATE EXCL
227 db_sequence_close (DB_SEQUENCE *seq, U32 flags = 0, SV *callback = &PL_sv_undef) 245 db_sequence_close (DB_SEQUENCE *seq, U32 flags = 0, SV *callback = 0)
228 db_sequence_get (DB_SEQUENCE *seq, DB_TXN_ornull *txnid, int delta, SV *seq_value, U32 flags = DB_TXN_NOSYNC, SV *callback = &PL_sv_undef) 246 db_sequence_get (DB_SEQUENCE *seq, DB_TXN_ornull *txnid, int delta, SV *seq_value, U32 flags = DB_TXN_NOSYNC, SV *callback = 0)
229 flags: TXN_NOSYNC 247 flags: TXN_NOSYNC
230 db_sequence_remove (DB_SEQUENCE *seq, DB_TXN_ornull *txnid = 0, U32 flags = 0, SV *callback = &PL_sv_undef) 248 db_sequence_remove (DB_SEQUENCE *seq, DB_TXN_ornull *txnid = 0, U32 flags = 0, SV *callback = 0)
231 flags: TXN_NOSYNC 249 flags: TXN_NOSYNC
232 250
233=head4 db_txn_finish (DB_TXN *txn, U32 flags = 0, SV *callback = &PL_sv_undef) 251=head3 db_txn_finish (DB_TXN *txn, U32 flags = 0, SV *callback = 0)
234 252
235This is not actually a Berkeley DB function but a BDB module 253This is not actually a Berkeley DB function but a BDB module
236extension. The background for this exytension is: It is very annoying to 254extension. The background for this exytension is: It is very annoying to
237have to check every single BDB function for error returns and provide a 255have to check every single BDB function for error returns and provide a
238codepath out of your transaction. While the BDB module still makes this 256codepath out of your transaction. While the BDB module still makes this
… …
264 282
265You can use the C<< $txn->failed >> method to check wether a transaction 283You can use the C<< $txn->failed >> method to check wether a transaction
266has failed in this way and abort further processing (excluding 284has failed in this way and abort further processing (excluding
267C<db_txn_finish>). 285C<db_txn_finish>).
268 286
287
269=head3 DB_ENV/database environment methods 288=head2 DB_ENV/database environment methods
270 289
271Methods available on DB_ENV/$env handles: 290Methods available on DB_ENV/$env handles:
272 291
273 DESTROY (DB_ENV_ornull *env) 292 DESTROY (DB_ENV_ornull *env)
274 CODE: 293 CODE:
… …
279 $int = $env->set_tmp_dir (const char *dir) 298 $int = $env->set_tmp_dir (const char *dir)
280 $int = $env->set_lg_dir (const char *dir) 299 $int = $env->set_lg_dir (const char *dir)
281 $int = $env->set_shm_key (long shm_key) 300 $int = $env->set_shm_key (long shm_key)
282 $int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0) 301 $int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0)
283 $int = $env->set_flags (U32 flags, int onoff = 1) 302 $int = $env->set_flags (U32 flags, int onoff = 1)
284 $int = $env->log_set_config (U32 flags, int onoff = 1) [v4.7] 303 $int = $env->log_set_config (U32 flags, int onoff = 1) (v4.7)
285 $int = $env->set_intermediate_dir_mode (const char *modestring) [v4.7] 304 $int = $env->set_intermediate_dir_mode (const char *modestring) (v4.7)
286 $env->set_errfile (FILE *errfile = 0) 305 $env->set_errfile (FILE *errfile = 0)
287 $env->set_msgfile (FILE *msgfile = 0) 306 $env->set_msgfile (FILE *msgfile = 0)
288 $int = $env->set_verbose (U32 which, int onoff = 1) 307 $int = $env->set_verbose (U32 which, int onoff = 1)
289 $int = $env->set_encrypt (const char *password, U32 flags = 0) 308 $int = $env->set_encrypt (const char *password, U32 flags = 0)
290 $int = $env->set_timeout (NV timeout_seconds, U32 flags = SET_TXN_TIMEOUT) 309 $int = $env->set_timeout (NV timeout_seconds, U32 flags = SET_TXN_TIMEOUT)
… …
302 $int = $env->mutex_set_max (U32 max) 321 $int = $env->mutex_set_max (U32 max)
303 $int = $env->mutex_set_align (U32 align) 322 $int = $env->mutex_set_align (U32 align)
304 323
305 $txn = $env->txn_begin (DB_TXN_ornull *parent = 0, U32 flags = 0) 324 $txn = $env->txn_begin (DB_TXN_ornull *parent = 0, U32 flags = 0)
306 flags: READ_COMMITTED READ_UNCOMMITTED TXN_NOSYNC TXN_NOWAIT TXN_SNAPSHOT TXN_SYNC TXN_WAIT TXN_WRITE_NOSYNC 325 flags: READ_COMMITTED READ_UNCOMMITTED TXN_NOSYNC TXN_NOWAIT TXN_SNAPSHOT TXN_SYNC TXN_WAIT TXN_WRITE_NOSYNC
326 $txn = $env->cdsgroup_begin; (v4.5)
307 327
308=head4 Example: 328=head3 Example:
309 329
310 use AnyEvent; 330 use AnyEvent;
311 use BDB; 331 use BDB;
312 332
313 our $FH; open $FH, "<&=" . BDB::poll_fileno; 333 our $FH; open $FH, "<&=" . BDB::poll_fileno;
… …
325 0600; 345 0600;
326 346
327 $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1); 347 $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1);
328 348
329 349
330=head3 DB/database methods 350=head2 DB/database methods
331 351
332Methods available on DB/$db handles: 352Methods available on DB/$db handles:
333 353
334 DESTROY (DB_ornull *db) 354 DESTROY (DB_ornull *db)
335 CODE: 355 CODE:
… …
361 381
362 $dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0) 382 $dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0)
363 flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT 383 flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT
364 $seq = $db->sequence (U32 flags = 0) 384 $seq = $db->sequence (U32 flags = 0)
365 385
366=head4 Example: 386=head3 Example:
367 387
368 my $db = db_create $env; 388 my $db = db_create $env;
369 db_open $db, undef, "table", undef, BDB::BTREE, BDB::AUTO_COMMIT | BDB::CREATE | BDB::READ_UNCOMMITTED, 0600; 389 db_open $db, undef, "table", undef, BDB::BTREE, BDB::AUTO_COMMIT | BDB::CREATE | BDB::READ_UNCOMMITTED, 0600;
370 390
371 for (1..1000) { 391 for (1..1000) {
… …
378 db_del $db, undef, "key $_" for 1..1000; 398 db_del $db, undef, "key $_" for 1..1000;
379 399
380 db_sync $db; 400 db_sync $db;
381 401
382 402
383=head3 DB_TXN/transaction methods 403=head2 DB_TXN/transaction methods
384 404
385Methods available on DB_TXN/$txn handles: 405Methods available on DB_TXN/$txn handles:
386 406
387 DESTROY (DB_TXN_ornull *txn) 407 DESTROY (DB_TXN_ornull *txn)
388 CODE: 408 CODE:
… …
394 414
395 $bool = $txn->failed 415 $bool = $txn->failed
396 # see db_txn_finish documentation, above 416 # see db_txn_finish documentation, above
397 417
398 418
399=head3 DBC/cursor methods 419=head2 DBC/cursor methods
400 420
401Methods available on DBC/$dbc handles: 421Methods available on DBC/$dbc handles:
402 422
403 DESTROY (DBC_ornull *dbc) 423 DESTROY (DBC_ornull *dbc)
404 CODE: 424 CODE:
405 if (dbc) 425 if (dbc)
406 dbc->c_close (dbc); 426 dbc->c_close (dbc);
407 427
408 $int = $cursor->set_priority ($priority = PRIORITY_*) 428 $int = $cursor->set_priority ($priority = PRIORITY_*) (v4.6)
409 429
410=head4 Example: 430=head3 Example:
411 431
412 my $c = $db->cursor; 432 my $c = $db->cursor;
413 433
414 for (;;) { 434 for (;;) {
415 db_c_get $c, my $key, my $data, BDB::NEXT; 435 db_c_get $c, my $key, my $data, BDB::NEXT;
… …
418 } 438 }
419 439
420 db_c_close $c; 440 db_c_close $c;
421 441
422 442
423=head3 DB_SEQUENCE/sequence methods 443=head2 DB_SEQUENCE/sequence methods
424 444
425Methods available on DB_SEQUENCE/$seq handles: 445Methods available on DB_SEQUENCE/$seq handles:
426 446
427 DESTROY (DB_SEQUENCE_ornull *seq) 447 DESTROY (DB_SEQUENCE_ornull *seq)
428 CODE: 448 CODE:
… …
433 $int = $seq->set_cachesize (U32 size) 453 $int = $seq->set_cachesize (U32 size)
434 $int = $seq->set_flags (U32 flags) 454 $int = $seq->set_flags (U32 flags)
435 flags: SEQ_DEC SEQ_INC SEQ_WRAP 455 flags: SEQ_DEC SEQ_INC SEQ_WRAP
436 $int = $seq->set_range (db_seq_t min, db_seq_t max) 456 $int = $seq->set_range (db_seq_t min, db_seq_t max)
437 457
438=head4 Example: 458=head3 Example:
439 459
440 my $seq = $db->sequence; 460 my $seq = $db->sequence;
441 461
442 db_sequence_open $seq, undef, "seq", BDB::CREATE; 462 db_sequence_open $seq, undef, "seq", BDB::CREATE;
443 db_sequence_get $seq, undef, 1, my $value; 463 db_sequence_get $seq, undef, 1, my $value;
444 464
445 465
446=head2 SUPPORT FUNCTIONS 466=head1 SUPPORT FUNCTIONS
447 467
448=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 468=head2 EVENT PROCESSING AND EVENT LOOP INTEGRATION
449 469
450=over 4 470=over 4
451 471
452=item $msg = BDB::strerror [$errno] 472=item $msg = BDB::strerror [$errno]
453 473
… …
540 BDB::poll_wait, BDB::poll_cb 560 BDB::poll_wait, BDB::poll_cb
541 while BDB::nreqs; 561 while BDB::nreqs;
542 562
543=back 563=back
544 564
545=head3 VERSION CHECKING 565=head2 VERSION CHECKING
546 566
547BerkeleyDB comes in various versions, many of them have minor 567BerkeleyDB comes in various versions, many of them have minor
548incompatibilities. This means that traditional "at least version x.x" 568incompatibilities. This means that traditional "at least version x.x"
549checks are often not sufficient. 569checks are often not sufficient.
550 570
571Example: set the log_autoremove option in a way compatible with <v4.7 and
572v4.7. Note the use of & on the constants to avoid triggering a compiletime
573bug when the symbol isn't available.
574
575 $DB_ENV->set_flags (&BDB::LOG_AUTOREMOVE ) if BDB::VERSION v0, v4.7;
576 $DB_ENV->log_set_config (&BDB::LOG_AUTO_REMOVE) if BDB::VERSION v4.7;
577
551=over 4 578=over 4
552 579
553=item BDB::VERSION 580=item BDB::VERSION
554 581
555The C<BDB::VERSION> function, when called without arguments, returns the 582The C<BDB::VERSION> function, when called without arguments, returns the
… …
582=back 609=back
583 610
584=cut 611=cut
585 612
586sub VERSION { 613sub VERSION {
614 # I was dumb enough to override the VERSION method here, so let's try
615 # to fix it up.
616
617 if ($_[0] eq __PACKAGE__) {
618 $VERSION
619 } else {
587 if (@_ > 0) { 620 if (@_ > 0) {
588 return undef if VERSION_v lt $_[0]; 621 return undef if VERSION_v lt $_[0];
589 if (@_ > 1) { 622 if (@_ > 1) {
590 return undef if VERSION_v ge $_[1]; 623 return undef if VERSION_v ge $_[1];
624 }
591 } 625 }
626
627 VERSION_v
592 } 628 }
593
594 VERSION_v
595} 629}
596 630
597=head3 CONTROLLING THE NUMBER OF THREADS 631=head2 CONTROLLING THE NUMBER OF THREADS
598 632
599=over 4 633=over 4
600 634
601=item BDB::min_parallel $nthreads 635=item BDB::min_parallel $nthreads
602 636
… …
663 697
664You can still queue as many requests as you want. Therefore, 698You can still queue as many requests as you want. Therefore,
665C<max_oustsanding> is mainly useful in simple scripts (with low values) or 699C<max_oustsanding> is mainly useful in simple scripts (with low values) or
666as a stop gap to shield against fatal memory overflow (with large values). 700as a stop gap to shield against fatal memory overflow (with large values).
667 701
668=item BDB::set_sync_prepare $cb 702=item $old_cb = BDB::set_sync_prepare $cb
669 703
670Sets a callback that is called whenever a request is created without an 704Sets a callback that is called whenever a request is created without an
671explicit callback. It has to return two code references. The first is used 705explicit callback. It has to return two code references. The first is used
672as the request callback (it should save the return status), and the second 706as the request callback (it should save the return status), and the second
673is called to wait until the first callback has been called (it must set 707is called to wait until the first callback has been called (it must set
674C<$!> to the return status). 708C<$!> to the return status).
675 709
676This mechanism can be used to include BDB into other event mechanisms, 710This mechanism can be used to include BDB into other event mechanisms,
677such as L<AnyEvent::BDB> or L<Coro::BDB>. 711such as L<Coro::BDB>.
678 712
679The default implementation works like this: 713To allow other, callback-based, events to be executed while callback-less
714ones are run, you could use this sync prepare function:
680 715
681 sub { 716 sub {
682 my $status; 717 my $status;
683 ( 718 (
684 sub { $status = $! }, 719 sub { $status = $! },
685 sub { BDB::poll while !defined $status; $! = $status }, 720 sub { BDB::poll while !defined $status; $! = $status },
686 ) 721 )
687 } 722 }
688 723
689It simply blocks the process till the request has finished and then sets 724It works by polling for results till the request has finished and then
690C<$!> to the return value. This means that if you don't use a callback, 725sets C<$!> to the return value. This means that if you don't use a
691BDB will simply fall back to synchronous operations. 726callback, BDB would simply fall back to synchronous operations.
727
728By default, or if the sync prepare function is set to C<undef>, is to
729execute callback-less BDB requests in the foreground thread, setting C<$!>
730to the return value, without polling for other events.
692 731
693=back 732=back
694 733
695=head3 STATISTICAL INFORMATION 734=head2 STATISTICAL INFORMATION
696 735
697=over 4 736=over 4
698 737
699=item BDB::nreqs 738=item BDB::nreqs
700 739
… …
718 757
719=back 758=back
720 759
721=cut 760=cut
722 761
723set_sync_prepare { 762set_sync_prepare (undef);
724 my $status;
725 (
726 sub {
727 $status = $!;
728 },
729 sub {
730 BDB::poll while !defined $status;
731 $! = $status;
732 },
733 )
734};
735 763
736min_parallel 8; 764min_parallel 8;
737 765
738END { flush } 766END { flush }
739 767
7401; 7681;
741 769
770=head1 COMMON PITFALLS
771
772=head2 Unexpected Crashes
773
774Remember that, by default, BDB will execute requests in parallel, in
775somewhat random order. That means that it is easy to run a C<db_get>
776request on thesa me database as a concurrent C<db_close> request, leading
777to a crash, silent data corruption, eventually the next world war on
778terrorism.
779
780If you only ever use foreground requests (without a callback), this will
781not be an issue.
782
783=head2 Unexpected Freezes or Deadlocks
784
785Remember that, by default, BDB will execute requests in parallel, which
786easily leads to deadlocks (even concurrent put's on the same database can
787deadlock).
788
789You either need to run deadlock detection (and handle the resulting
790errors), or make sure only one process ever updates the database, ine one
791thread, e.g. by using only foreground requests (without a callback).
792
742=head2 FORK BEHAVIOUR 793=head1 FORK BEHAVIOUR
743 794
744This module should do "the right thing" when the process using it forks: 795This module should do "the right thing" when the process using it forks:
745 796
746Before the fork, BDB enters a quiescent state where no requests 797Before the fork, BDB enters a quiescent state where no requests
747can be added in other threads and no results will be processed. After 798can be added in other threads and no results will be processed. After
… …
757 808
758Win32 note: there is no fork on win32, and perls emulation of it is too 809Win32 note: there is no fork on win32, and perls emulation of it is too
759broken to be supported, so do not use BDB in a windows pseudo-fork, better 810broken to be supported, so do not use BDB in a windows pseudo-fork, better
760yet, switch to a more capable platform. 811yet, switch to a more capable platform.
761 812
762=head2 MEMORY USAGE 813=head1 MEMORY USAGE
763 814
764Per-request usage: 815Per-request usage:
765 816
766Each aio request uses - depending on your architecture - around 100-200 817Each aio request uses - depending on your architecture - around 100-200
767bytes of memory. In addition, stat requests need a stat buffer (possibly 818bytes of memory. In addition, stat requests need a stat buffer (possibly
… …
776 827
777In the execution phase, some aio requests require more memory for 828In the execution phase, some aio requests require more memory for
778temporary buffers, and each thread requires a stack and other data 829temporary buffers, and each thread requires a stack and other data
779structures (usually around 16k-128k, depending on the OS). 830structures (usually around 16k-128k, depending on the OS).
780 831
832=head1 WIN32 FILENAMES/DATABASE NAME MESS
833
834Perl on Win32 supports only ASCII filenames (the reason is that it abuses
835an internal flag to store wether a filename is Unicode or ANSI, but that
836flag is used for somethign else in the perl core, so there is no way to
837detect wether a filename is ANSI or Unicode-encoded). The BDB module
838tries to work around this issue by assuming that the filename is an ANSI
839filename and BDB was built for unicode support.
840
781=head1 KNOWN BUGS 841=head1 KNOWN BUGS
782 842
783Known bugs will be fixed in the next release, except: 843Known bugs will be fixed in the next release, except:
784 844
785 If you use a transaction in any request, and the request returns 845 If you use a transaction in any request, and the request returns

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