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Comparing BDB/BDB.pm (file contents):
Revision 1.46 by root, Thu Jul 17 12:09:56 2008 UTC vs.
Revision 1.69 by root, Tue Feb 2 04:28:06 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 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
113our $VERSION; 112our $VERSION;
114 113
115BEGIN { 114BEGIN {
116 $VERSION = '1.7'; 115 $VERSION = '1.91';
117 116
118 our @BDB_REQ = qw( 117 our @BDB_REQ = qw(
119 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
120 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 db_env_lsn_reset db_env_fileid_reset
121 db_open db_close db_compact db_sync db_upgrade 121 db_open db_close db_compact db_sync db_verify db_upgrade
122 db_put db_exists db_get db_pget db_del db_key_range 122 db_put db_exists db_get db_pget db_del db_key_range
123 db_txn_commit db_txn_abort db_txn_finish 123 db_txn_commit db_txn_abort db_txn_finish
124 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
125 db_sequence_open db_sequence_close 125 db_sequence_open db_sequence_close
126 db_sequence_get db_sequence_remove 126 db_sequence_get db_sequence_remove
… …
135 135
136 require XSLoader; 136 require XSLoader;
137 XSLoader::load ("BDB", $VERSION); 137 XSLoader::load ("BDB", $VERSION);
138} 138}
139 139
140=head2 WIN32 FILENAMES/DATABASE NAME MESS
141
142Perl on Win32 supports only ASCII filenames (the reason is that it abuses
143an internal flag to store wether a filename is Unicode or ANSI, but that
144flag is used for somethign else in the perl core, so there is no way to
145detect wether a filename is ANSI or Unicode-encoded). The BDB module
146tries to work around this issue by assuming that the filename is an ANSI
147filename and BDB was built for unicode support.
148
149=head2 BERKELEYDB FUNCTIONS 140=head1 BERKELEYDB FUNCTIONS
150 141
151All of these are functions. The create functions simply return a new 142All of these are functions. The create functions simply return a new
152object and never block. All the remaining functions take an optional 143object and never block. All the remaining functions take an optional
153callback as last argument. If it is missing, then the function will be 144callback as last argument. If it is missing, then the function will be
154executed synchronously. In both cases, C<$!> will reflect the return value 145executed synchronously. In both cases, C<$!> will reflect the return value
… …
193 184
194 db_env_txn_checkpoint $db_env, 0, 0, 0, undef; 185 db_env_txn_checkpoint $db_env, 0, 0, 0, undef;
195 db_env_txn_checkpoint $db_env, 0, 0, 0; 186 db_env_txn_checkpoint $db_env, 0, 0, 0;
196 db_env_txn_checkpoint $db_env, 0; 187 db_env_txn_checkpoint $db_env, 0;
197 188
198=head3 BDB functions 189=head2 BDB functions
199 190
200Functions in the BDB namespace, exported by default: 191Functions in the BDB namespace, exported by default:
201 192
202 $env = db_env_create (U32 env_flags = 0) 193 $env = db_env_create (U32 env_flags = 0)
203 flags: RPCCLIENT 194 flags: RPCCLIENT
204 195
205 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)
206 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
207 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)
208 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)
209 flags: FORCE 200 flags: FORCE
210 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)
211 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
212 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)
213 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)
214 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)
215 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)
208 db_env_lsn_reset (DB_ENV *env, bdb_filename db, U32 flags = 0, SV *callback = 0)
209 db_env_fileid_reset (DB_ENV *env, bdb_filename db, U32 flags = 0, SV *callback = 0)
216 210
217 $db = db_create (DB_ENV *env = 0, U32 flags = 0) 211 $db = db_create (DB_ENV *env = 0, U32 flags = 0)
218 flags: XA_CREATE 212 flags: XA_CREATE
219 213
220 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) 214 db_open (DB *db, DB_TXN_ornull *txnid, bdb_filename file, bdb_filename database, int type, U32 flags, int mode, SV *callback = 0)
221 flags: AUTO_COMMIT CREATE EXCL MULTIVERSION NOMMAP RDONLY READ_UNCOMMITTED THREAD TRUNCATE 215 flags: AUTO_COMMIT CREATE EXCL MULTIVERSION NOMMAP RDONLY READ_UNCOMMITTED THREAD TRUNCATE
222 db_close (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) 216 db_close (DB *db, U32 flags = 0, SV *callback = 0)
223 flags: DB_NOSYNC 217 flags: DB_NOSYNC
218 db_verify (DB *db, bdb_filename file, bdb_filename database = 0, SV *dummy = 0, U32 flags = 0, SV *callback = 0)
224 db_upgrade (DB *db, bdb_filename file, U32 flags = 0, SV *callback = &PL_sv_undef) 219 db_upgrade (DB *db, bdb_filename file, U32 flags = 0, SV *callback = 0)
225 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) 220 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)
226 flags: FREELIST_ONLY FREE_SPACE 221 flags: FREELIST_ONLY FREE_SPACE
227 db_sync (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) 222 db_sync (DB *db, U32 flags = 0, SV *callback = 0)
228 db_key_range (DB *db, DB_TXN_ornull *txn, SV *key, SV *key_range, U32 flags = 0, SV *callback = &PL_sv_undef) 223 db_key_range (DB *db, DB_TXN_ornull *txn, SV *key, SV *key_range, U32 flags = 0, SV *callback = 0)
229 db_put (DB *db, DB_TXN_ornull *txn, SV *key, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) 224 db_put (DB *db, DB_TXN_ornull *txn, SV *key, SV *data, U32 flags = 0, SV *callback = 0)
230 flags: APPEND NODUPDATA NOOVERWRITE 225 flags: APPEND NODUPDATA NOOVERWRITE
231 db_exists (DB *db, DB_TXN_ornull *txn, SV *key, U32 flags = 0, SV *callback = 0) (v4.6) 226 db_exists (DB *db, DB_TXN_ornull *txn, SV *key, U32 flags = 0, SV *callback = 0) (v4.6)
232 db_get (DB *db, DB_TXN_ornull *txn, SV *key, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) 227 db_get (DB *db, DB_TXN_ornull *txn, SV *key, SV *data, U32 flags = 0, SV *callback = 0)
233 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
234 db_pget (DB *db, DB_TXN_ornull *txn, SV *key, SV *pkey, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) 229 db_pget (DB *db, DB_TXN_ornull *txn, SV *key, SV *pkey, SV *data, U32 flags = 0, SV *callback = 0)
235 flags: CONSUME CONSUME_WAIT GET_BOTH SET_RECNO MULTIPLE READ_COMMITTED READ_UNCOMMITTED RMW 230 flags: CONSUME CONSUME_WAIT GET_BOTH SET_RECNO MULTIPLE READ_COMMITTED READ_UNCOMMITTED RMW
236 db_del (DB *db, DB_TXN_ornull *txn, SV *key, U32 flags = 0, SV *callback = &PL_sv_undef) 231 db_del (DB *db, DB_TXN_ornull *txn, SV *key, U32 flags = 0, SV *callback = 0)
237 db_txn_commit (DB_TXN *txn, U32 flags = 0, SV *callback = &PL_sv_undef) 232 db_txn_commit (DB_TXN *txn, U32 flags = 0, SV *callback = 0)
238 flags: TXN_NOSYNC TXN_SYNC 233 flags: TXN_NOSYNC TXN_SYNC
239 db_txn_abort (DB_TXN *txn, SV *callback = &PL_sv_undef) 234 db_txn_abort (DB_TXN *txn, SV *callback = 0)
240 235
241 db_c_close (DBC *dbc, SV *callback = &PL_sv_undef) 236 db_c_close (DBC *dbc, SV *callback = 0)
242 db_c_count (DBC *dbc, SV *count, U32 flags = 0, SV *callback = &PL_sv_undef) 237 db_c_count (DBC *dbc, SV *count, U32 flags = 0, SV *callback = 0)
243 db_c_put (DBC *dbc, SV *key, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) 238 db_c_put (DBC *dbc, SV *key, SV *data, U32 flags = 0, SV *callback = 0)
244 flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA 239 flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA
245 db_c_get (DBC *dbc, SV *key, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) 240 db_c_get (DBC *dbc, SV *key, SV *data, U32 flags = 0, SV *callback = 0)
246 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 241 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
247 db_c_pget (DBC *dbc, SV *key, SV *pkey, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) 242 db_c_pget (DBC *dbc, SV *key, SV *pkey, SV *data, U32 flags = 0, SV *callback = 0)
248 db_c_del (DBC *dbc, U32 flags = 0, SV *callback = &PL_sv_undef) 243 db_c_del (DBC *dbc, U32 flags = 0, SV *callback = 0)
249 244
250 db_sequence_open (DB_SEQUENCE *seq, DB_TXN_ornull *txnid, SV *key, U32 flags = 0, SV *callback = &PL_sv_undef) 245 db_sequence_open (DB_SEQUENCE *seq, DB_TXN_ornull *txnid, SV *key, U32 flags = 0, SV *callback = 0)
251 flags: CREATE EXCL 246 flags: CREATE EXCL
252 db_sequence_close (DB_SEQUENCE *seq, U32 flags = 0, SV *callback = &PL_sv_undef) 247 db_sequence_close (DB_SEQUENCE *seq, U32 flags = 0, SV *callback = 0)
253 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) 248 db_sequence_get (DB_SEQUENCE *seq, DB_TXN_ornull *txnid, int delta, SV *seq_value, U32 flags = DB_TXN_NOSYNC, SV *callback = 0)
254 flags: TXN_NOSYNC 249 flags: TXN_NOSYNC
255 db_sequence_remove (DB_SEQUENCE *seq, DB_TXN_ornull *txnid = 0, U32 flags = 0, SV *callback = &PL_sv_undef) 250 db_sequence_remove (DB_SEQUENCE *seq, DB_TXN_ornull *txnid = 0, U32 flags = 0, SV *callback = 0)
256 flags: TXN_NOSYNC 251 flags: TXN_NOSYNC
257 252
258=head4 db_txn_finish (DB_TXN *txn, U32 flags = 0, SV *callback = &PL_sv_undef) 253=head3 db_txn_finish (DB_TXN *txn, U32 flags = 0, SV *callback = 0)
259 254
260This is not actually a Berkeley DB function but a BDB module 255This is not actually a Berkeley DB function but a BDB module
261extension. The background for this exytension is: It is very annoying to 256extension. The background for this exytension is: It is very annoying to
262have to check every single BDB function for error returns and provide a 257have to check every single BDB function for error returns and provide a
263codepath out of your transaction. While the BDB module still makes this 258codepath out of your transaction. While the BDB module still makes this
… …
289 284
290You can use the C<< $txn->failed >> method to check wether a transaction 285You can use the C<< $txn->failed >> method to check wether a transaction
291has failed in this way and abort further processing (excluding 286has failed in this way and abort further processing (excluding
292C<db_txn_finish>). 287C<db_txn_finish>).
293 288
289
294=head3 DB_ENV/database environment methods 290=head2 DB_ENV/database environment methods
295 291
296Methods available on DB_ENV/$env handles: 292Methods available on DB_ENV/$env handles:
297 293
298 DESTROY (DB_ENV_ornull *env) 294 DESTROY (DB_ENV_ornull *env)
299 CODE: 295 CODE:
… …
329 325
330 $txn = $env->txn_begin (DB_TXN_ornull *parent = 0, U32 flags = 0) 326 $txn = $env->txn_begin (DB_TXN_ornull *parent = 0, U32 flags = 0)
331 flags: READ_COMMITTED READ_UNCOMMITTED TXN_NOSYNC TXN_NOWAIT TXN_SNAPSHOT TXN_SYNC TXN_WAIT TXN_WRITE_NOSYNC 327 flags: READ_COMMITTED READ_UNCOMMITTED TXN_NOSYNC TXN_NOWAIT TXN_SNAPSHOT TXN_SYNC TXN_WAIT TXN_WRITE_NOSYNC
332 $txn = $env->cdsgroup_begin; (v4.5) 328 $txn = $env->cdsgroup_begin; (v4.5)
333 329
334=head4 Example: 330=head3 Example:
335 331
336 use AnyEvent; 332 use AnyEvent;
337 use BDB; 333 use BDB;
338 334
339 our $FH; open $FH, "<&=" . BDB::poll_fileno; 335 our $FH; open $FH, "<&=" . BDB::poll_fileno;
… …
351 0600; 347 0600;
352 348
353 $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1); 349 $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1);
354 350
355 351
356=head3 DB/database methods 352=head2 DB/database methods
357 353
358Methods available on DB/$db handles: 354Methods available on DB/$db handles:
359 355
360 DESTROY (DB_ornull *db) 356 DESTROY (DB_ornull *db)
361 CODE: 357 CODE:
… …
387 383
388 $dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0) 384 $dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0)
389 flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT 385 flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT
390 $seq = $db->sequence (U32 flags = 0) 386 $seq = $db->sequence (U32 flags = 0)
391 387
392=head4 Example: 388=head3 Example:
393 389
394 my $db = db_create $env; 390 my $db = db_create $env;
395 db_open $db, undef, "table", undef, BDB::BTREE, BDB::AUTO_COMMIT | BDB::CREATE | BDB::READ_UNCOMMITTED, 0600; 391 db_open $db, undef, "table", undef, BDB::BTREE, BDB::AUTO_COMMIT | BDB::CREATE | BDB::READ_UNCOMMITTED, 0600;
396 392
397 for (1..1000) { 393 for (1..1000) {
… …
404 db_del $db, undef, "key $_" for 1..1000; 400 db_del $db, undef, "key $_" for 1..1000;
405 401
406 db_sync $db; 402 db_sync $db;
407 403
408 404
409=head3 DB_TXN/transaction methods 405=head2 DB_TXN/transaction methods
410 406
411Methods available on DB_TXN/$txn handles: 407Methods available on DB_TXN/$txn handles:
412 408
413 DESTROY (DB_TXN_ornull *txn) 409 DESTROY (DB_TXN_ornull *txn)
414 CODE: 410 CODE:
… …
420 416
421 $bool = $txn->failed 417 $bool = $txn->failed
422 # see db_txn_finish documentation, above 418 # see db_txn_finish documentation, above
423 419
424 420
425=head3 DBC/cursor methods 421=head2 DBC/cursor methods
426 422
427Methods available on DBC/$dbc handles: 423Methods available on DBC/$dbc handles:
428 424
429 DESTROY (DBC_ornull *dbc) 425 DESTROY (DBC_ornull *dbc)
430 CODE: 426 CODE:
431 if (dbc) 427 if (dbc)
432 dbc->c_close (dbc); 428 dbc->c_close (dbc);
433 429
434 $int = $cursor->set_priority ($priority = PRIORITY_*) (v4.6) 430 $int = $cursor->set_priority ($priority = PRIORITY_*) (v4.6)
435 431
436=head4 Example: 432=head3 Example:
437 433
438 my $c = $db->cursor; 434 my $c = $db->cursor;
439 435
440 for (;;) { 436 for (;;) {
441 db_c_get $c, my $key, my $data, BDB::NEXT; 437 db_c_get $c, my $key, my $data, BDB::NEXT;
… …
444 } 440 }
445 441
446 db_c_close $c; 442 db_c_close $c;
447 443
448 444
449=head3 DB_SEQUENCE/sequence methods 445=head2 DB_SEQUENCE/sequence methods
450 446
451Methods available on DB_SEQUENCE/$seq handles: 447Methods available on DB_SEQUENCE/$seq handles:
452 448
453 DESTROY (DB_SEQUENCE_ornull *seq) 449 DESTROY (DB_SEQUENCE_ornull *seq)
454 CODE: 450 CODE:
… …
459 $int = $seq->set_cachesize (U32 size) 455 $int = $seq->set_cachesize (U32 size)
460 $int = $seq->set_flags (U32 flags) 456 $int = $seq->set_flags (U32 flags)
461 flags: SEQ_DEC SEQ_INC SEQ_WRAP 457 flags: SEQ_DEC SEQ_INC SEQ_WRAP
462 $int = $seq->set_range (db_seq_t min, db_seq_t max) 458 $int = $seq->set_range (db_seq_t min, db_seq_t max)
463 459
464=head4 Example: 460=head3 Example:
465 461
466 my $seq = $db->sequence; 462 my $seq = $db->sequence;
467 463
468 db_sequence_open $seq, undef, "seq", BDB::CREATE; 464 db_sequence_open $seq, undef, "seq", BDB::CREATE;
469 db_sequence_get $seq, undef, 1, my $value; 465 db_sequence_get $seq, undef, 1, my $value;
470 466
471 467
472=head2 SUPPORT FUNCTIONS 468=head1 SUPPORT FUNCTIONS
473 469
474=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 470=head2 EVENT PROCESSING AND EVENT LOOP INTEGRATION
475 471
476=over 4 472=over 4
477 473
478=item $msg = BDB::strerror [$errno] 474=item $msg = BDB::strerror [$errno]
479 475
… …
566 BDB::poll_wait, BDB::poll_cb 562 BDB::poll_wait, BDB::poll_cb
567 while BDB::nreqs; 563 while BDB::nreqs;
568 564
569=back 565=back
570 566
571=head3 VERSION CHECKING 567=head2 VERSION CHECKING
572 568
573BerkeleyDB comes in various versions, many of them have minor 569BerkeleyDB comes in various versions, many of them have minor
574incompatibilities. This means that traditional "at least version x.x" 570incompatibilities. This means that traditional "at least version x.x"
575checks are often not sufficient. 571checks are often not sufficient.
576 572
577Example: set the log_autoremove option in a way compatible with <v.47 and 573Example: set the log_autoremove option in a way compatible with <v4.7 and
578v4.7. Note the use of & on the constants to avoid triggering a compiletime 574v4.7. Note the use of & on the constants to avoid triggering a compiletime
579bug when the symbol isn't available. 575bug when the symbol isn't available.
580 576
581 $DB_ENV->set_flags (&BDB::LOG_AUTOREMOVE ) if BDB::VERSION v0, v4.7; 577 $DB_ENV->set_flags (&BDB::LOG_AUTOREMOVE ) if BDB::VERSION v0, v4.7;
582 $DB_ENV->log_set_config (&BDB::LOG_AUTO_REMOVE) if BDB::VERSION v4.7; 578 $DB_ENV->log_set_config (&BDB::LOG_AUTO_REMOVE) if BDB::VERSION v4.7;
… …
632 628
633 VERSION_v 629 VERSION_v
634 } 630 }
635} 631}
636 632
637=head3 CONTROLLING THE NUMBER OF THREADS 633=head2 CONTROLLING THE NUMBER OF THREADS
638 634
639=over 4 635=over 4
640 636
641=item BDB::min_parallel $nthreads 637=item BDB::min_parallel $nthreads
642 638
… …
703 699
704You can still queue as many requests as you want. Therefore, 700You can still queue as many requests as you want. Therefore,
705C<max_oustsanding> is mainly useful in simple scripts (with low values) or 701C<max_oustsanding> is mainly useful in simple scripts (with low values) or
706as a stop gap to shield against fatal memory overflow (with large values). 702as a stop gap to shield against fatal memory overflow (with large values).
707 703
708=item BDB::set_sync_prepare $cb 704=item $old_cb = BDB::set_sync_prepare $cb
709 705
710Sets a callback that is called whenever a request is created without an 706Sets a callback that is called whenever a request is created without an
711explicit callback. It has to return two code references. The first is used 707explicit callback. It has to return two code references. The first is used
712as the request callback (it should save the return status), and the second 708as the request callback (it should save the return status), and the second
713is called to wait until the first callback has been called (it must set 709is called to wait until the first callback has been called (it must set
714C<$!> to the return status). 710C<$!> to the return status).
715 711
716This mechanism can be used to include BDB into other event mechanisms, 712This mechanism can be used to include BDB into other event mechanisms,
717such as L<AnyEvent::BDB> or L<Coro::BDB>. 713such as L<Coro::BDB>.
718 714
719The default implementation works like this: 715To allow other, callback-based, events to be executed while callback-less
716ones are run, you could use this sync prepare function:
720 717
721 sub { 718 sub {
722 my $status; 719 my $status;
723 ( 720 (
724 sub { $status = $! }, 721 sub { $status = $! },
725 sub { BDB::poll while !defined $status; $! = $status }, 722 sub { BDB::poll while !defined $status; $! = $status },
726 ) 723 )
727 } 724 }
728 725
729It simply blocks the process till the request has finished and then sets 726It works by polling for results till the request has finished and then
730C<$!> to the return value. This means that if you don't use a callback, 727sets C<$!> to the return value. This means that if you don't use a
731BDB will simply fall back to synchronous operations. 728callback, BDB would simply fall back to synchronous operations.
729
730By default, or if the sync prepare function is set to C<undef>, is to
731execute callback-less BDB requests in the foreground thread, setting C<$!>
732to the return value, without polling for other events.
732 733
733=back 734=back
734 735
735=head3 STATISTICAL INFORMATION 736=head2 STATISTICAL INFORMATION
736 737
737=over 4 738=over 4
738 739
739=item BDB::nreqs 740=item BDB::nreqs
740 741
… …
758 759
759=back 760=back
760 761
761=cut 762=cut
762 763
763set_sync_prepare { 764set_sync_prepare (undef);
764 my $status;
765 (
766 sub {
767 $status = $!;
768 },
769 sub {
770 BDB::poll while !defined $status;
771 $! = $status;
772 },
773 )
774};
775 765
776min_parallel 8; 766min_parallel 8;
777 767
778END { flush } 768END { flush }
779 769
7801; 7701;
781 771
772=head1 COMMON PITFALLS
773
774=head2 Unexpected Crashes
775
776Remember that, by default, BDB will execute requests in parallel, in
777somewhat random order. That means that it is easy to run a C<db_get>
778request on the same database as a concurrent C<db_close> request, leading
779to a crash, silent data corruption, eventually the next world war on
780terrorism.
781
782If you only ever use foreground requests (without a callback), this will
783not be an issue (unless you use threads).
784
785=head2 Unexpected Freezes or Deadlocks
786
787Remember that, by default, BDB will execute requests in parallel, which
788easily leads to deadlocks (even concurrent put's on the same database can
789deadlock).
790
791You either need to run deadlock detection (and handle the resulting
792errors), or make sure only one process ever updates the database, ine one
793thread, e.g. by using only foreground requests (without a callback).
794
782=head2 FORK BEHAVIOUR 795=head1 FORK BEHAVIOUR
783 796
784This module should do "the right thing" when the process using it forks: 797This module should do "the right thing" when the process using it forks:
785 798
786Before the fork, BDB enters a quiescent state where no requests 799Before the fork, BDB enters a quiescent state where no requests
787can be added in other threads and no results will be processed. After 800can be added in other threads and no results will be processed. After
… …
797 810
798Win32 note: there is no fork on win32, and perls emulation of it is too 811Win32 note: there is no fork on win32, and perls emulation of it is too
799broken to be supported, so do not use BDB in a windows pseudo-fork, better 812broken to be supported, so do not use BDB in a windows pseudo-fork, better
800yet, switch to a more capable platform. 813yet, switch to a more capable platform.
801 814
802=head2 MEMORY USAGE 815=head1 MEMORY USAGE
803 816
804Per-request usage: 817Per-request usage:
805 818
806Each aio request uses - depending on your architecture - around 100-200 819Each aio request uses - depending on your architecture - around 100-200
807bytes of memory. In addition, stat requests need a stat buffer (possibly 820bytes of memory. In addition, stat requests need a stat buffer (possibly
… …
816 829
817In the execution phase, some aio requests require more memory for 830In the execution phase, some aio requests require more memory for
818temporary buffers, and each thread requires a stack and other data 831temporary buffers, and each thread requires a stack and other data
819structures (usually around 16k-128k, depending on the OS). 832structures (usually around 16k-128k, depending on the OS).
820 833
834=head1 WIN32 FILENAMES/DATABASE NAME MESS
835
836Perl on Win32 supports only ASCII filenames (the reason is that it abuses
837an internal flag to store wether a filename is Unicode or ANSI, but that
838flag is used for somethign else in the perl core, so there is no way to
839detect wether a filename is ANSI or Unicode-encoded). The BDB module
840tries to work around this issue by assuming that the filename is an ANSI
841filename and BDB was built for unicode support.
842
821=head1 KNOWN BUGS 843=head1 KNOWN BUGS
822 844
823Known bugs will be fixed in the next release, except: 845Known bugs will be fixed in the next release, except:
824 846
825 If you use a transaction in any request, and the request returns 847 If you use a transaction in any request, and the request returns

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