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Comparing BDB/BDB.pm (file contents):
Revision 1.43 by root, Wed Jul 9 21:00:13 2008 UTC vs.
Revision 1.70 by root, Thu Jan 18 16:45:27 2018 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 = '1.7'; 115 $VERSION = '1.92';
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 db_env_lsn_reset db_env_fileid_reset
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 );
… …
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
… …
191 184
192 db_env_txn_checkpoint $db_env, 0, 0, 0, undef; 185 db_env_txn_checkpoint $db_env, 0, 0, 0, undef;
193 db_env_txn_checkpoint $db_env, 0, 0, 0; 186 db_env_txn_checkpoint $db_env, 0, 0, 0;
194 db_env_txn_checkpoint $db_env, 0; 187 db_env_txn_checkpoint $db_env, 0;
195 188
196=head3 BDB functions 189=head2 BDB functions
197 190
198Functions in the BDB namespace, exported by default: 191Functions in the BDB namespace, exported by default:
199 192
200 $env = db_env_create (U32 env_flags = 0) 193 $env = db_env_create (U32 env_flags = 0)
201 flags: RPCCLIENT 194 flags: RPCCLIENT
202 195
203 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)
204 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
205 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)
206 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)
207 flags: FORCE 200 flags: FORCE
208 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)
209 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
210 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)
211 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)
212 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)
213 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)
214 210
215 $db = db_create (DB_ENV *env = 0, U32 flags = 0) 211 $db = db_create (DB_ENV *env = 0, U32 flags = 0)
216 flags: XA_CREATE 212 flags: XA_CREATE
217 213
218 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)
219 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
220 db_close (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) 216 db_close (DB *db, U32 flags = 0, SV *callback = 0)
221 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)
222 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)
223 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)
224 flags: FREELIST_ONLY FREE_SPACE 221 flags: FREELIST_ONLY FREE_SPACE
225 db_sync (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) 222 db_sync (DB *db, U32 flags = 0, SV *callback = 0)
226 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)
227 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)
228 flags: APPEND NODUPDATA NOOVERWRITE 225 flags: APPEND NODUPDATA NOOVERWRITE
226 db_exists (DB *db, DB_TXN_ornull *txn, SV *key, U32 flags = 0, SV *callback = 0) (v4.6)
229 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)
230 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
231 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)
232 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
233 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)
234 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)
235 flags: TXN_NOSYNC TXN_SYNC 233 flags: TXN_NOSYNC TXN_SYNC
236 db_txn_abort (DB_TXN *txn, SV *callback = &PL_sv_undef) 234 db_txn_abort (DB_TXN *txn, SV *callback = 0)
237 235
238 db_c_close (DBC *dbc, SV *callback = &PL_sv_undef) 236 db_c_close (DBC *dbc, SV *callback = 0)
239 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)
240 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)
241 flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA 239 flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA
242 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)
243 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
244 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)
245 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)
246 244
247 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)
248 flags: CREATE EXCL 246 flags: CREATE EXCL
249 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)
250 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)
251 flags: TXN_NOSYNC 249 flags: TXN_NOSYNC
252 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)
253 flags: TXN_NOSYNC 251 flags: TXN_NOSYNC
254 252
255=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)
256 254
257This is not actually a Berkeley DB function but a BDB module 255This is not actually a Berkeley DB function but a BDB module
258extension. The background for this exytension is: It is very annoying to 256extension. The background for this exytension is: It is very annoying to
259have 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
260codepath out of your transaction. While the BDB module still makes this 258codepath out of your transaction. While the BDB module still makes this
… …
286 284
287You can use the C<< $txn->failed >> method to check wether a transaction 285You can use the C<< $txn->failed >> method to check wether a transaction
288has failed in this way and abort further processing (excluding 286has failed in this way and abort further processing (excluding
289C<db_txn_finish>). 287C<db_txn_finish>).
290 288
289
291=head3 DB_ENV/database environment methods 290=head2 DB_ENV/database environment methods
292 291
293Methods available on DB_ENV/$env handles: 292Methods available on DB_ENV/$env handles:
294 293
295 DESTROY (DB_ENV_ornull *env) 294 DESTROY (DB_ENV_ornull *env)
296 CODE: 295 CODE:
… …
301 $int = $env->set_tmp_dir (const char *dir) 300 $int = $env->set_tmp_dir (const char *dir)
302 $int = $env->set_lg_dir (const char *dir) 301 $int = $env->set_lg_dir (const char *dir)
303 $int = $env->set_shm_key (long shm_key) 302 $int = $env->set_shm_key (long shm_key)
304 $int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0) 303 $int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0)
305 $int = $env->set_flags (U32 flags, int onoff = 1) 304 $int = $env->set_flags (U32 flags, int onoff = 1)
306 $int = $env->log_set_config (U32 flags, int onoff = 1) [v4.7] 305 $int = $env->log_set_config (U32 flags, int onoff = 1) (v4.7)
307 $int = $env->set_intermediate_dir_mode (const char *modestring) [v4.7] 306 $int = $env->set_intermediate_dir_mode (const char *modestring) (v4.7)
308 $env->set_errfile (FILE *errfile = 0) 307 $env->set_errfile (FILE *errfile = 0)
309 $env->set_msgfile (FILE *msgfile = 0) 308 $env->set_msgfile (FILE *msgfile = 0)
310 $int = $env->set_verbose (U32 which, int onoff = 1) 309 $int = $env->set_verbose (U32 which, int onoff = 1)
311 $int = $env->set_encrypt (const char *password, U32 flags = 0) 310 $int = $env->set_encrypt (const char *password, U32 flags = 0)
312 $int = $env->set_timeout (NV timeout_seconds, U32 flags = SET_TXN_TIMEOUT) 311 $int = $env->set_timeout (NV timeout_seconds, U32 flags = SET_TXN_TIMEOUT)
… …
324 $int = $env->mutex_set_max (U32 max) 323 $int = $env->mutex_set_max (U32 max)
325 $int = $env->mutex_set_align (U32 align) 324 $int = $env->mutex_set_align (U32 align)
326 325
327 $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)
328 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
329 $txn = $env->cdsgroup_begin; 328 $txn = $env->cdsgroup_begin; (v4.5)
330 329
331=head4 Example: 330=head3 Example:
332 331
333 use AnyEvent; 332 use AnyEvent;
334 use BDB; 333 use BDB;
335 334
336 our $FH; open $FH, "<&=" . BDB::poll_fileno; 335 our $FH; open $FH, "<&=" . BDB::poll_fileno;
… …
348 0600; 347 0600;
349 348
350 $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1); 349 $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1);
351 350
352 351
353=head3 DB/database methods 352=head2 DB/database methods
354 353
355Methods available on DB/$db handles: 354Methods available on DB/$db handles:
356 355
357 DESTROY (DB_ornull *db) 356 DESTROY (DB_ornull *db)
358 CODE: 357 CODE:
… …
384 383
385 $dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0) 384 $dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0)
386 flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT 385 flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT
387 $seq = $db->sequence (U32 flags = 0) 386 $seq = $db->sequence (U32 flags = 0)
388 387
389=head4 Example: 388=head3 Example:
390 389
391 my $db = db_create $env; 390 my $db = db_create $env;
392 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;
393 392
394 for (1..1000) { 393 for (1..1000) {
… …
401 db_del $db, undef, "key $_" for 1..1000; 400 db_del $db, undef, "key $_" for 1..1000;
402 401
403 db_sync $db; 402 db_sync $db;
404 403
405 404
406=head3 DB_TXN/transaction methods 405=head2 DB_TXN/transaction methods
407 406
408Methods available on DB_TXN/$txn handles: 407Methods available on DB_TXN/$txn handles:
409 408
410 DESTROY (DB_TXN_ornull *txn) 409 DESTROY (DB_TXN_ornull *txn)
411 CODE: 410 CODE:
… …
417 416
418 $bool = $txn->failed 417 $bool = $txn->failed
419 # see db_txn_finish documentation, above 418 # see db_txn_finish documentation, above
420 419
421 420
422=head3 DBC/cursor methods 421=head2 DBC/cursor methods
423 422
424Methods available on DBC/$dbc handles: 423Methods available on DBC/$dbc handles:
425 424
426 DESTROY (DBC_ornull *dbc) 425 DESTROY (DBC_ornull *dbc)
427 CODE: 426 CODE:
428 if (dbc) 427 if (dbc)
429 dbc->c_close (dbc); 428 dbc->c_close (dbc);
430 429
431 $int = $cursor->set_priority ($priority = PRIORITY_*) 430 $int = $cursor->set_priority ($priority = PRIORITY_*) (v4.6)
432 431
433=head4 Example: 432=head3 Example:
434 433
435 my $c = $db->cursor; 434 my $c = $db->cursor;
436 435
437 for (;;) { 436 for (;;) {
438 db_c_get $c, my $key, my $data, BDB::NEXT; 437 db_c_get $c, my $key, my $data, BDB::NEXT;
… …
441 } 440 }
442 441
443 db_c_close $c; 442 db_c_close $c;
444 443
445 444
446=head3 DB_SEQUENCE/sequence methods 445=head2 DB_SEQUENCE/sequence methods
447 446
448Methods available on DB_SEQUENCE/$seq handles: 447Methods available on DB_SEQUENCE/$seq handles:
449 448
450 DESTROY (DB_SEQUENCE_ornull *seq) 449 DESTROY (DB_SEQUENCE_ornull *seq)
451 CODE: 450 CODE:
… …
456 $int = $seq->set_cachesize (U32 size) 455 $int = $seq->set_cachesize (U32 size)
457 $int = $seq->set_flags (U32 flags) 456 $int = $seq->set_flags (U32 flags)
458 flags: SEQ_DEC SEQ_INC SEQ_WRAP 457 flags: SEQ_DEC SEQ_INC SEQ_WRAP
459 $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)
460 459
461=head4 Example: 460=head3 Example:
462 461
463 my $seq = $db->sequence; 462 my $seq = $db->sequence;
464 463
465 db_sequence_open $seq, undef, "seq", BDB::CREATE; 464 db_sequence_open $seq, undef, "seq", BDB::CREATE;
466 db_sequence_get $seq, undef, 1, my $value; 465 db_sequence_get $seq, undef, 1, my $value;
467 466
468 467
469=head2 SUPPORT FUNCTIONS 468=head1 SUPPORT FUNCTIONS
470 469
471=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 470=head2 EVENT PROCESSING AND EVENT LOOP INTEGRATION
472 471
473=over 4 472=over 4
474 473
475=item $msg = BDB::strerror [$errno] 474=item $msg = BDB::strerror [$errno]
476 475
… …
563 BDB::poll_wait, BDB::poll_cb 562 BDB::poll_wait, BDB::poll_cb
564 while BDB::nreqs; 563 while BDB::nreqs;
565 564
566=back 565=back
567 566
568=head3 VERSION CHECKING 567=head2 VERSION CHECKING
569 568
570BerkeleyDB comes in various versions, many of them have minor 569BerkeleyDB comes in various versions, many of them have minor
571incompatibilities. This means that traditional "at least version x.x" 570incompatibilities. This means that traditional "at least version x.x"
572checks are often not sufficient. 571checks are often not sufficient.
573 572
574Example: 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
575v4.7. 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
576bug when the symbol isn't available. 575bug when the symbol isn't available.
577 576
578 $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;
579 $DB_ENV->log_set_config (&BDB::LOG_AUTO_REMOVE) if BDB::VERSION v4.7; 578 $DB_ENV->log_set_config (&BDB::LOG_AUTO_REMOVE) if BDB::VERSION v4.7;
… …
612=back 611=back
613 612
614=cut 613=cut
615 614
616sub VERSION { 615sub VERSION {
616 # I was dumb enough to override the VERSION method here, so let's try
617 # to fix it up.
618
619 if ($_[0] eq __PACKAGE__) {
620 $VERSION
621 } else {
617 if (@_ > 0) { 622 if (@_ > 0) {
618 return undef if VERSION_v lt $_[0]; 623 return undef if VERSION_v lt $_[0];
619 if (@_ > 1) { 624 if (@_ > 1) {
620 return undef if VERSION_v ge $_[1]; 625 return undef if VERSION_v ge $_[1];
626 }
621 } 627 }
628
629 VERSION_v
622 } 630 }
623
624 VERSION_v
625} 631}
626 632
627=head3 CONTROLLING THE NUMBER OF THREADS 633=head2 CONTROLLING THE NUMBER OF THREADS
628 634
629=over 4 635=over 4
630 636
631=item BDB::min_parallel $nthreads 637=item BDB::min_parallel $nthreads
632 638
… …
693 699
694You can still queue as many requests as you want. Therefore, 700You can still queue as many requests as you want. Therefore,
695C<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
696as 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).
697 703
698=item BDB::set_sync_prepare $cb 704=item $old_cb = BDB::set_sync_prepare $cb
699 705
700Sets a callback that is called whenever a request is created without an 706Sets a callback that is called whenever a request is created without an
701explicit callback. It has to return two code references. The first is used 707explicit callback. It has to return two code references. The first is used
702as the request callback (it should save the return status), and the second 708as the request callback (it should save the return status), and the second
703is called to wait until the first callback has been called (it must set 709is called to wait until the first callback has been called (it must set
704C<$!> to the return status). 710C<$!> to the return status).
705 711
706This mechanism can be used to include BDB into other event mechanisms, 712This mechanism can be used to include BDB into other event mechanisms,
707such as L<AnyEvent::BDB> or L<Coro::BDB>. 713such as L<Coro::BDB>.
708 714
709The 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:
710 717
711 sub { 718 sub {
712 my $status; 719 my $status;
713 ( 720 (
714 sub { $status = $! }, 721 sub { $status = $! },
715 sub { BDB::poll while !defined $status; $! = $status }, 722 sub { BDB::poll while !defined $status; $! = $status },
716 ) 723 )
717 } 724 }
718 725
719It simply blocks the process till the request has finished and then sets 726It works by polling for results till the request has finished and then
720C<$!> to the return value. This means that if you don't use a callback, 727sets C<$!> to the return value. This means that if you don't use a
721BDB will simply fall back to synchronous operations. 728callback, BDB would simply fall back to synchronous operations.
729
730By default, or if the sync prepare function is set to C<undef>, is to
731execute callback-less BDB requests in the foreground thread, setting C<$!>
732to the return value, without polling for other events.
722 733
723=back 734=back
724 735
725=head3 STATISTICAL INFORMATION 736=head2 STATISTICAL INFORMATION
726 737
727=over 4 738=over 4
728 739
729=item BDB::nreqs 740=item BDB::nreqs
730 741
… …
748 759
749=back 760=back
750 761
751=cut 762=cut
752 763
753set_sync_prepare { 764set_sync_prepare (undef);
754 my $status;
755 (
756 sub {
757 $status = $!;
758 },
759 sub {
760 BDB::poll while !defined $status;
761 $! = $status;
762 },
763 )
764};
765 765
766min_parallel 8; 766min_parallel 8;
767 767
768END { flush } 768END { flush }
769 769
7701; 7701;
771 771
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
772=head2 FORK BEHAVIOUR 795=head1 FORK BEHAVIOUR
773 796
774This 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:
775 798
776Before the fork, BDB enters a quiescent state where no requests 799Before the fork, BDB enters a quiescent state where no requests
777can 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
… …
787 810
788Win32 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
789broken 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
790yet, switch to a more capable platform. 813yet, switch to a more capable platform.
791 814
792=head2 MEMORY USAGE 815=head1 MEMORY USAGE
793 816
794Per-request usage: 817Per-request usage:
795 818
796Each aio request uses - depending on your architecture - around 100-200 819Each aio request uses - depending on your architecture - around 100-200
797bytes of memory. In addition, stat requests need a stat buffer (possibly 820bytes of memory. In addition, stat requests need a stat buffer (possibly
… …
806 829
807In the execution phase, some aio requests require more memory for 830In the execution phase, some aio requests require more memory for
808temporary buffers, and each thread requires a stack and other data 831temporary buffers, and each thread requires a stack and other data
809structures (usually around 16k-128k, depending on the OS). 832structures (usually around 16k-128k, depending on the OS).
810 833
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
811=head1 KNOWN BUGS 843=head1 KNOWN BUGS
812 844
813Known bugs will be fixed in the next release, except: 845Known bugs will be fixed in the next release, except:
814 846
815 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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