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Revision 1.13 by root, Sat Sep 27 12:02:21 2008 UTC vs.
Revision 1.16 by root, Wed Aug 5 11:52:34 2009 UTC

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25 db_sync $db; 25 db_sync $db;
26 26
27 # when you also use Coro, management is easy: 27 # when you also use Coro, management is easy:
28 use Coro::BDB; 28 use Coro::BDB;
29 29
30 # automatic event loop intergration with AnyEvent: 30 # automatic event loop integration with AnyEvent:
31 use AnyEvent::BDB; 31 use AnyEvent::BDB;
32 32
33 # automatic result processing with EV: 33 # automatic result processing with EV:
34 my $WATCHER = EV::io BDB::poll_fileno, EV::READ, \&BDB::poll_cb; 34 my $WATCHER = EV::io BDB::poll_fileno, EV::READ, \&BDB::poll_cb;
35 35
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86 Request has reached the end of its lifetime and holds no resources 86 Request has reached the end of its lifetime and holds no resources
87 anymore (except possibly for the Perl object, but its connection to 87 anymore (except possibly for the Perl object, but its connection to
88 the actual aio request is severed and calling its methods will 88 the actual aio request is severed and calling its methods will
89 either do nothing or result in a runtime error). 89 either do nothing or result in a runtime error).
90 90
91 WIN32 FILENAMES/DATABASE NAME MESS
92 Perl on Win32 supports only ASCII filenames (the reason is that it
93 abuses an internal flag to store wether a filename is Unicode or ANSI,
94 but that flag is used for somethign else in the perl core, so there is
95 no way to detect wether a filename is ANSI or Unicode-encoded). The BDB
96 module tries to work around this issue by assuming that the filename is
97 an ANSI filename and BDB was built for unicode support.
98
99 BERKELEYDB FUNCTIONS 91BERKELEYDB FUNCTIONS
100 All of these are functions. The create functions simply return a new 92 All of these are functions. The create functions simply return a new
101 object and never block. All the remaining functions take an optional 93 object and never block. All the remaining functions take an optional
102 callback as last argument. If it is missing, then the function will be 94 callback as last argument. If it is missing, then the function will be
103 executed synchronously. In both cases, $! will reflect the return value 95 executed synchronously. In both cases, $! will reflect the return value
104 of the function. 96 of the function.
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142 134
143 db_env_txn_checkpoint $db_env, 0, 0, 0, undef; 135 db_env_txn_checkpoint $db_env, 0, 0, 0, undef;
144 db_env_txn_checkpoint $db_env, 0, 0, 0; 136 db_env_txn_checkpoint $db_env, 0, 0, 0;
145 db_env_txn_checkpoint $db_env, 0; 137 db_env_txn_checkpoint $db_env, 0;
146 138
147 BDB functions 139 BDB functions
148 Functions in the BDB namespace, exported by default: 140 Functions in the BDB namespace, exported by default:
149 141
150 $env = db_env_create (U32 env_flags = 0) 142 $env = db_env_create (U32 env_flags = 0)
151 flags: RPCCLIENT 143 flags: RPCCLIENT
152 144
153 db_env_open (DB_ENV *env, bdb_filename db_home, U32 open_flags, int mode, SV *callback = &PL_sv_undef) 145 db_env_open (DB_ENV *env, bdb_filename db_home, U32 open_flags, int mode, SV *callback = 0)
154 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 146 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
155 db_env_close (DB_ENV *env, U32 flags = 0, SV *callback = &PL_sv_undef) 147 db_env_close (DB_ENV *env, U32 flags = 0, SV *callback = 0)
156 db_env_txn_checkpoint (DB_ENV *env, U32 kbyte = 0, U32 min = 0, U32 flags = 0, SV *callback = &PL_sv_undef) 148 db_env_txn_checkpoint (DB_ENV *env, U32 kbyte = 0, U32 min = 0, U32 flags = 0, SV *callback = 0)
157 flags: FORCE 149 flags: FORCE
158 db_env_lock_detect (DB_ENV *env, U32 flags = 0, U32 atype = DB_LOCK_DEFAULT, SV *dummy = 0, SV *callback = &PL_sv_undef) 150 db_env_lock_detect (DB_ENV *env, U32 flags = 0, U32 atype = DB_LOCK_DEFAULT, SV *dummy = 0, SV *callback = 0)
159 atype: LOCK_DEFAULT LOCK_EXPIRE LOCK_MAXLOCKS LOCK_MAXWRITE LOCK_MINLOCKS LOCK_MINWRITE LOCK_OLDEST LOCK_RANDOM LOCK_YOUNGEST 151 atype: LOCK_DEFAULT LOCK_EXPIRE LOCK_MAXLOCKS LOCK_MAXWRITE LOCK_MINLOCKS LOCK_MINWRITE LOCK_OLDEST LOCK_RANDOM LOCK_YOUNGEST
160 db_env_memp_sync (DB_ENV *env, SV *dummy = 0, SV *callback = &PL_sv_undef) 152 db_env_memp_sync (DB_ENV *env, SV *dummy = 0, SV *callback = 0)
161 db_env_memp_trickle (DB_ENV *env, int percent, SV *dummy = 0, SV *callback = &PL_sv_undef) 153 db_env_memp_trickle (DB_ENV *env, int percent, SV *dummy = 0, SV *callback = 0)
162 db_env_dbremove (DB_ENV *env, DB_TXN_ornull *txnid, bdb_filename file, bdb_filename database, U32 flags = 0, SV *callback = &PL_sv_undef) 154 db_env_dbremove (DB_ENV *env, DB_TXN_ornull *txnid, bdb_filename file, bdb_filename database, U32 flags = 0, SV *callback = 0)
163 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) 155 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)
156 db_env_log_archive (DB_ENV *env, SV *listp, U32 flags = 0, SV *callback = 0)
164 157
165 $db = db_create (DB_ENV *env = 0, U32 flags = 0) 158 $db = db_create (DB_ENV *env = 0, U32 flags = 0)
166 flags: XA_CREATE 159 flags: XA_CREATE
167 160
168 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) 161 db_open (DB *db, DB_TXN_ornull *txnid, bdb_filename file, bdb_filename database, int type, U32 flags, int mode, SV *callback = 0)
169 flags: AUTO_COMMIT CREATE EXCL MULTIVERSION NOMMAP RDONLY READ_UNCOMMITTED THREAD TRUNCATE 162 flags: AUTO_COMMIT CREATE EXCL MULTIVERSION NOMMAP RDONLY READ_UNCOMMITTED THREAD TRUNCATE
170 db_close (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) 163 db_close (DB *db, U32 flags = 0, SV *callback = 0)
171 flags: DB_NOSYNC 164 flags: DB_NOSYNC
165 db_verify (DB *db, bdb_filename file, bdb_filename database = 0, SV *dummy = 0, U32 flags = 0, SV *callback = 0)
172 db_upgrade (DB *db, bdb_filename file, U32 flags = 0, SV *callback = &PL_sv_undef) 166 db_upgrade (DB *db, bdb_filename file, U32 flags = 0, SV *callback = 0)
173 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) 167 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)
174 flags: FREELIST_ONLY FREE_SPACE 168 flags: FREELIST_ONLY FREE_SPACE
175 db_sync (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) 169 db_sync (DB *db, U32 flags = 0, SV *callback = 0)
176 db_key_range (DB *db, DB_TXN_ornull *txn, SV *key, SV *key_range, U32 flags = 0, SV *callback = &PL_sv_undef) 170 db_key_range (DB *db, DB_TXN_ornull *txn, SV *key, SV *key_range, U32 flags = 0, SV *callback = 0)
177 db_put (DB *db, DB_TXN_ornull *txn, SV *key, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) 171 db_put (DB *db, DB_TXN_ornull *txn, SV *key, SV *data, U32 flags = 0, SV *callback = 0)
178 flags: APPEND NODUPDATA NOOVERWRITE 172 flags: APPEND NODUPDATA NOOVERWRITE
179 db_exists (DB *db, DB_TXN_ornull *txn, SV *key, U32 flags = 0, SV *callback = 0) (v4.6) 173 db_exists (DB *db, DB_TXN_ornull *txn, SV *key, U32 flags = 0, SV *callback = 0) (v4.6)
180 db_get (DB *db, DB_TXN_ornull *txn, SV *key, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) 174 db_get (DB *db, DB_TXN_ornull *txn, SV *key, SV *data, U32 flags = 0, SV *callback = 0)
181 flags: CONSUME CONSUME_WAIT GET_BOTH SET_RECNO MULTIPLE READ_COMMITTED READ_UNCOMMITTED RMW 175 flags: CONSUME CONSUME_WAIT GET_BOTH SET_RECNO MULTIPLE READ_COMMITTED READ_UNCOMMITTED RMW
182 db_pget (DB *db, DB_TXN_ornull *txn, SV *key, SV *pkey, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) 176 db_pget (DB *db, DB_TXN_ornull *txn, SV *key, SV *pkey, SV *data, U32 flags = 0, SV *callback = 0)
183 flags: CONSUME CONSUME_WAIT GET_BOTH SET_RECNO MULTIPLE READ_COMMITTED READ_UNCOMMITTED RMW 177 flags: CONSUME CONSUME_WAIT GET_BOTH SET_RECNO MULTIPLE READ_COMMITTED READ_UNCOMMITTED RMW
184 db_del (DB *db, DB_TXN_ornull *txn, SV *key, U32 flags = 0, SV *callback = &PL_sv_undef) 178 db_del (DB *db, DB_TXN_ornull *txn, SV *key, U32 flags = 0, SV *callback = 0)
185 db_txn_commit (DB_TXN *txn, U32 flags = 0, SV *callback = &PL_sv_undef) 179 db_txn_commit (DB_TXN *txn, U32 flags = 0, SV *callback = 0)
186 flags: TXN_NOSYNC TXN_SYNC 180 flags: TXN_NOSYNC TXN_SYNC
187 db_txn_abort (DB_TXN *txn, SV *callback = &PL_sv_undef) 181 db_txn_abort (DB_TXN *txn, SV *callback = 0)
188 182
189 db_c_close (DBC *dbc, SV *callback = &PL_sv_undef) 183 db_c_close (DBC *dbc, SV *callback = 0)
190 db_c_count (DBC *dbc, SV *count, U32 flags = 0, SV *callback = &PL_sv_undef) 184 db_c_count (DBC *dbc, SV *count, U32 flags = 0, SV *callback = 0)
191 db_c_put (DBC *dbc, SV *key, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) 185 db_c_put (DBC *dbc, SV *key, SV *data, U32 flags = 0, SV *callback = 0)
192 flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA 186 flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA
193 db_c_get (DBC *dbc, SV *key, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) 187 db_c_get (DBC *dbc, SV *key, SV *data, U32 flags = 0, SV *callback = 0)
194 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 188 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
195 db_c_pget (DBC *dbc, SV *key, SV *pkey, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) 189 db_c_pget (DBC *dbc, SV *key, SV *pkey, SV *data, U32 flags = 0, SV *callback = 0)
196 db_c_del (DBC *dbc, U32 flags = 0, SV *callback = &PL_sv_undef) 190 db_c_del (DBC *dbc, U32 flags = 0, SV *callback = 0)
197 191
198 db_sequence_open (DB_SEQUENCE *seq, DB_TXN_ornull *txnid, SV *key, U32 flags = 0, SV *callback = &PL_sv_undef) 192 db_sequence_open (DB_SEQUENCE *seq, DB_TXN_ornull *txnid, SV *key, U32 flags = 0, SV *callback = 0)
199 flags: CREATE EXCL 193 flags: CREATE EXCL
200 db_sequence_close (DB_SEQUENCE *seq, U32 flags = 0, SV *callback = &PL_sv_undef) 194 db_sequence_close (DB_SEQUENCE *seq, U32 flags = 0, SV *callback = 0)
201 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) 195 db_sequence_get (DB_SEQUENCE *seq, DB_TXN_ornull *txnid, int delta, SV *seq_value, U32 flags = DB_TXN_NOSYNC, SV *callback = 0)
202 flags: TXN_NOSYNC 196 flags: TXN_NOSYNC
203 db_sequence_remove (DB_SEQUENCE *seq, DB_TXN_ornull *txnid = 0, U32 flags = 0, SV *callback = &PL_sv_undef) 197 db_sequence_remove (DB_SEQUENCE *seq, DB_TXN_ornull *txnid = 0, U32 flags = 0, SV *callback = 0)
204 flags: TXN_NOSYNC 198 flags: TXN_NOSYNC
205 199
206 db_txn_finish (DB_TXN *txn, U32 flags = 0, SV *callback = &PL_sv_undef) 200 db_txn_finish (DB_TXN *txn, U32 flags = 0, SV *callback = 0)
207 This is not actually a Berkeley DB function but a BDB module extension. 201 This is not actually a Berkeley DB function but a BDB module extension.
208 The background for this exytension is: It is very annoying to have to 202 The background for this exytension is: It is very annoying to have to
209 check every single BDB function for error returns and provide a codepath 203 check every single BDB function for error returns and provide a codepath
210 out of your transaction. While the BDB module still makes this possible, 204 out of your transaction. While the BDB module still makes this possible,
211 it contains the following extensions: 205 it contains the following extensions:
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236 230
237 You can use the "$txn->failed" method to check wether a transaction has 231 You can use the "$txn->failed" method to check wether a transaction has
238 failed in this way and abort further processing (excluding 232 failed in this way and abort further processing (excluding
239 "db_txn_finish"). 233 "db_txn_finish").
240 234
241 DB_ENV/database environment methods 235 DB_ENV/database environment methods
242 Methods available on DB_ENV/$env handles: 236 Methods available on DB_ENV/$env handles:
243 237
244 DESTROY (DB_ENV_ornull *env) 238 DESTROY (DB_ENV_ornull *env)
245 CODE: 239 CODE:
246 if (env) 240 if (env)
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295 BDB::INIT_LOCK | BDB::INIT_LOG | BDB::INIT_MPOOL | BDB::INIT_TXN | BDB::RECOVER | BDB::USE_ENVIRON | BDB::CREATE, 289 BDB::INIT_LOCK | BDB::INIT_LOG | BDB::INIT_MPOOL | BDB::INIT_TXN | BDB::RECOVER | BDB::USE_ENVIRON | BDB::CREATE,
296 0600; 290 0600;
297 291
298 $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1); 292 $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1);
299 293
300 DB/database methods 294 DB/database methods
301 Methods available on DB/$db handles: 295 Methods available on DB/$db handles:
302 296
303 DESTROY (DB_ornull *db) 297 DESTROY (DB_ornull *db)
304 CODE: 298 CODE:
305 if (db) 299 if (db)
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345 339
346 db_del $db, undef, "key $_" for 1..1000; 340 db_del $db, undef, "key $_" for 1..1000;
347 341
348 db_sync $db; 342 db_sync $db;
349 343
350 DB_TXN/transaction methods 344 DB_TXN/transaction methods
351 Methods available on DB_TXN/$txn handles: 345 Methods available on DB_TXN/$txn handles:
352 346
353 DESTROY (DB_TXN_ornull *txn) 347 DESTROY (DB_TXN_ornull *txn)
354 CODE: 348 CODE:
355 if (txn) 349 if (txn)
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359 flags: SET_LOCK_TIMEOUT SET_TXN_TIMEOUT 353 flags: SET_LOCK_TIMEOUT SET_TXN_TIMEOUT
360 354
361 $bool = $txn->failed 355 $bool = $txn->failed
362 # see db_txn_finish documentation, above 356 # see db_txn_finish documentation, above
363 357
364 DBC/cursor methods 358 DBC/cursor methods
365 Methods available on DBC/$dbc handles: 359 Methods available on DBC/$dbc handles:
366 360
367 DESTROY (DBC_ornull *dbc) 361 DESTROY (DBC_ornull *dbc)
368 CODE: 362 CODE:
369 if (dbc) 363 if (dbc)
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380 last if $!; 374 last if $!;
381 } 375 }
382 376
383 db_c_close $c; 377 db_c_close $c;
384 378
385 DB_SEQUENCE/sequence methods 379 DB_SEQUENCE/sequence methods
386 Methods available on DB_SEQUENCE/$seq handles: 380 Methods available on DB_SEQUENCE/$seq handles:
387 381
388 DESTROY (DB_SEQUENCE_ornull *seq) 382 DESTROY (DB_SEQUENCE_ornull *seq)
389 CODE: 383 CODE:
390 if (seq) 384 if (seq)
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396 flags: SEQ_DEC SEQ_INC SEQ_WRAP 390 flags: SEQ_DEC SEQ_INC SEQ_WRAP
397 $int = $seq->set_range (db_seq_t min, db_seq_t max) 391 $int = $seq->set_range (db_seq_t min, db_seq_t max)
398 392
399 Example: 393 Example:
400 my $seq = $db->sequence; 394 my $seq = $db->sequence;
401 395
402 db_sequence_open $seq, undef, "seq", BDB::CREATE; 396 db_sequence_open $seq, undef, "seq", BDB::CREATE;
403 db_sequence_get $seq, undef, 1, my $value; 397 db_sequence_get $seq, undef, 1, my $value;
404 398
405 SUPPORT FUNCTIONS 399SUPPORT FUNCTIONS
406 EVENT PROCESSING AND EVENT LOOP INTEGRATION 400 EVENT PROCESSING AND EVENT LOOP INTEGRATION
407 $msg = BDB::strerror [$errno] 401 $msg = BDB::strerror [$errno]
408 Returns the string corresponding to the given errno value. If no 402 Returns the string corresponding to the given errno value. If no
409 argument is given, use $!. 403 argument is given, use $!.
410 404
411 Note that the BDB module also patches the $! variable directly, so 405 Note that the BDB module also patches the $! variable directly, so
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488 Strictly equivalent to: 482 Strictly equivalent to:
489 483
490 BDB::poll_wait, BDB::poll_cb 484 BDB::poll_wait, BDB::poll_cb
491 while BDB::nreqs; 485 while BDB::nreqs;
492 486
493 VERSION CHECKING 487 VERSION CHECKING
494 BerkeleyDB comes in various versions, many of them have minor 488 BerkeleyDB comes in various versions, many of them have minor
495 incompatibilities. This means that traditional "at least version x.x" 489 incompatibilities. This means that traditional "at least version x.x"
496 checks are often not sufficient. 490 checks are often not sufficient.
497 491
498 Example: set the log_autoremove option in a way compatible with <v4.7 492 Example: set the log_autoremove option in a way compatible with <v4.7
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528 Example: check wether version is strictly less then v4.7. 522 Example: check wether version is strictly less then v4.7.
529 523
530 BDB::VERSION v0, v4.7 524 BDB::VERSION v0, v4.7
531 or die "version 4.7 is not yet supported"; 525 or die "version 4.7 is not yet supported";
532 526
533 CONTROLLING THE NUMBER OF THREADS 527 CONTROLLING THE NUMBER OF THREADS
534 BDB::min_parallel $nthreads 528 BDB::min_parallel $nthreads
535 Set the minimum number of BDB threads to $nthreads. The current 529 Set the minimum number of BDB threads to $nthreads. The current
536 default is 8, which means eight asynchronous operations can execute 530 default is 8, which means eight asynchronous operations can execute
537 concurrently at any one time (the number of outstanding requests, 531 concurrently at any one time (the number of outstanding requests,
538 however, is unlimited). 532 however, is unlimited).
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627 621
628 By default, or if the sync prepare function is set to "undef", is to 622 By default, or if the sync prepare function is set to "undef", is to
629 execute callback-less BDB requests in the foreground thread, setting 623 execute callback-less BDB requests in the foreground thread, setting
630 $! to the return value, without polling for other events. 624 $! to the return value, without polling for other events.
631 625
632 STATISTICAL INFORMATION 626 STATISTICAL INFORMATION
633 BDB::nreqs 627 BDB::nreqs
634 Returns the number of requests currently in the ready, execute or 628 Returns the number of requests currently in the ready, execute or
635 pending states (i.e. for which their callback has not been invoked 629 pending states (i.e. for which their callback has not been invoked
636 yet). 630 yet).
637 631
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646 640
647 BDB::npending 641 BDB::npending
648 Returns the number of requests currently in the pending state 642 Returns the number of requests currently in the pending state
649 (executed, but not yet processed by poll_cb). 643 (executed, but not yet processed by poll_cb).
650 644
645COMMON PITFALLS
646 Unexpected Crashes
647 Remember that, by default, BDB will execute requests in parallel, in
648 somewhat random order. That means that it is easy to run a "db_get"
649 request on thesa me database as a concurrent "db_close" request, leading
650 to a crash, silent data corruption, eventually the next world war on
651 terrorism.
652
653 If you only ever use foreground requests (without a callback), this will
654 not be an issue.
655
656 Unexpected Freezes or Deadlocks
657 Remember that, by default, BDB will execute requests in parallel, which
658 easily leads to deadlocks (even concurrent put's on the same database
659 can deadlock).
660
661 You either need to run deadlock detection (and handle the resulting
662 errors), or make sure only one process ever updates the database, ine
663 one thread, e.g. by using only foreground requests (without a callback).
664
651 FORK BEHAVIOUR 665FORK BEHAVIOUR
652 This module should do "the right thing" when the process using it forks: 666 This module should do "the right thing" when the process using it forks:
653 667
654 Before the fork, BDB enters a quiescent state where no requests can be 668 Before the fork, BDB enters a quiescent state where no requests can be
655 added in other threads and no results will be processed. After the fork 669 added in other threads and no results will be processed. After the fork
656 the parent simply leaves the quiescent state and continues 670 the parent simply leaves the quiescent state and continues
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665 679
666 Win32 note: there is no fork on win32, and perls emulation of it is too 680 Win32 note: there is no fork on win32, and perls emulation of it is too
667 broken to be supported, so do not use BDB in a windows pseudo-fork, 681 broken to be supported, so do not use BDB in a windows pseudo-fork,
668 better yet, switch to a more capable platform. 682 better yet, switch to a more capable platform.
669 683
670 MEMORY USAGE 684MEMORY USAGE
671 Per-request usage: 685 Per-request usage:
672 686
673 Each aio request uses - depending on your architecture - around 100-200 687 Each aio request uses - depending on your architecture - around 100-200
674 bytes of memory. In addition, stat requests need a stat buffer (possibly 688 bytes of memory. In addition, stat requests need a stat buffer (possibly
675 a few hundred bytes), readdir requires a result buffer and so on. Perl 689 a few hundred bytes), readdir requires a result buffer and so on. Perl
… …
683 697
684 In the execution phase, some aio requests require more memory for 698 In the execution phase, some aio requests require more memory for
685 temporary buffers, and each thread requires a stack and other data 699 temporary buffers, and each thread requires a stack and other data
686 structures (usually around 16k-128k, depending on the OS). 700 structures (usually around 16k-128k, depending on the OS).
687 701
702WIN32 FILENAMES/DATABASE NAME MESS
703 Perl on Win32 supports only ASCII filenames (the reason is that it
704 abuses an internal flag to store wether a filename is Unicode or ANSI,
705 but that flag is used for somethign else in the perl core, so there is
706 no way to detect wether a filename is ANSI or Unicode-encoded). The BDB
707 module tries to work around this issue by assuming that the filename is
708 an ANSI filename and BDB was built for unicode support.
709
688KNOWN BUGS 710KNOWN BUGS
689 Known bugs will be fixed in the next release, except: 711 Known bugs will be fixed in the next release, except:
690 712
691 If you use a transaction in any request, and the request returns 713 If you use a transaction in any request, and the request returns
692 with an operating system error or DB_LOCK_NOTGRANTED, the internal 714 with an operating system error or DB_LOCK_NOTGRANTED, the internal

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