… | |
… | |
108 | no warnings; |
108 | no warnings; |
109 | use strict 'vars'; |
109 | use strict 'vars'; |
110 | |
110 | |
111 | use base 'Exporter'; |
111 | use base 'Exporter'; |
112 | |
112 | |
|
|
113 | our $VERSION; |
|
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114 | |
113 | BEGIN { |
115 | BEGIN { |
114 | our $VERSION = '1.7'; |
116 | $VERSION = '1.81'; |
115 | |
117 | |
116 | our @BDB_REQ = qw( |
118 | our @BDB_REQ = qw( |
117 | db_env_open db_env_close db_env_txn_checkpoint db_env_lock_detect |
119 | db_env_open db_env_close db_env_txn_checkpoint db_env_lock_detect |
118 | db_env_memp_sync db_env_memp_trickle db_env_dbrename db_env_dbremove |
120 | db_env_memp_sync db_env_memp_trickle db_env_dbrename db_env_dbremove |
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121 | db_env_log_archive |
119 | db_open db_close db_compact db_sync db_upgrade |
122 | db_open db_close db_compact db_sync db_upgrade |
120 | db_put db_exists db_get db_pget db_del db_key_range |
123 | db_put db_exists db_get db_pget db_del db_key_range |
121 | db_txn_commit db_txn_abort db_txn_finish |
124 | 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 |
125 | 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 |
126 | db_sequence_open db_sequence_close |
… | |
… | |
133 | |
136 | |
134 | require XSLoader; |
137 | require XSLoader; |
135 | XSLoader::load ("BDB", $VERSION); |
138 | XSLoader::load ("BDB", $VERSION); |
136 | } |
139 | } |
137 | |
140 | |
138 | =head2 WIN32 FILENAMES/DATABASE NAME MESS |
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139 | |
|
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140 | Perl on Win32 supports only ASCII filenames (the reason is that it abuses |
|
|
141 | an internal flag to store wether a filename is Unicode or ANSI, but that |
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142 | flag is used for somethign else in the perl core, so there is no way to |
|
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143 | detect wether a filename is ANSI or Unicode-encoded). The BDB module |
|
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144 | tries to work around this issue by assuming that the filename is an ANSI |
|
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145 | filename and BDB was built for unicode support. |
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|
146 | |
|
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147 | =head2 BERKELEYDB FUNCTIONS |
141 | =head1 BERKELEYDB FUNCTIONS |
148 | |
142 | |
149 | All of these are functions. The create functions simply return a new |
143 | All of these are functions. The create functions simply return a new |
150 | object and never block. All the remaining functions take an optional |
144 | object and never block. All the remaining functions take an optional |
151 | callback as last argument. If it is missing, then the function will be |
145 | callback as last argument. If it is missing, then the function will be |
152 | executed synchronously. In both cases, C<$!> will reflect the return value |
146 | executed synchronously. In both cases, C<$!> will reflect the return value |
… | |
… | |
191 | |
185 | |
192 | db_env_txn_checkpoint $db_env, 0, 0, 0, undef; |
186 | db_env_txn_checkpoint $db_env, 0, 0, 0, undef; |
193 | db_env_txn_checkpoint $db_env, 0, 0, 0; |
187 | db_env_txn_checkpoint $db_env, 0, 0, 0; |
194 | db_env_txn_checkpoint $db_env, 0; |
188 | db_env_txn_checkpoint $db_env, 0; |
195 | |
189 | |
196 | =head3 BDB functions |
190 | =head2 BDB functions |
197 | |
191 | |
198 | Functions in the BDB namespace, exported by default: |
192 | Functions in the BDB namespace, exported by default: |
199 | |
193 | |
200 | $env = db_env_create (U32 env_flags = 0) |
194 | $env = db_env_create (U32 env_flags = 0) |
201 | flags: RPCCLIENT |
195 | flags: RPCCLIENT |
… | |
… | |
209 | atype: LOCK_DEFAULT LOCK_EXPIRE LOCK_MAXLOCKS LOCK_MAXWRITE LOCK_MINLOCKS LOCK_MINWRITE LOCK_OLDEST LOCK_RANDOM LOCK_YOUNGEST |
203 | atype: LOCK_DEFAULT LOCK_EXPIRE LOCK_MAXLOCKS LOCK_MAXWRITE LOCK_MINLOCKS LOCK_MINWRITE LOCK_OLDEST LOCK_RANDOM LOCK_YOUNGEST |
210 | db_env_memp_sync (DB_ENV *env, SV *dummy = 0, SV *callback = &PL_sv_undef) |
204 | db_env_memp_sync (DB_ENV *env, SV *dummy = 0, SV *callback = &PL_sv_undef) |
211 | db_env_memp_trickle (DB_ENV *env, int percent, SV *dummy = 0, SV *callback = &PL_sv_undef) |
205 | db_env_memp_trickle (DB_ENV *env, int percent, SV *dummy = 0, SV *callback = &PL_sv_undef) |
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) |
206 | db_env_dbremove (DB_ENV *env, DB_TXN_ornull *txnid, bdb_filename file, bdb_filename database, U32 flags = 0, SV *callback = &PL_sv_undef) |
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) |
207 | db_env_dbrename (DB_ENV *env, DB_TXN_ornull *txnid, bdb_filename file, bdb_filename database, bdb_filename newname, U32 flags = 0, SV *callback = &PL_sv_undef) |
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208 | db_env_log_archive (DB_ENV *env, SV *listp, U32 flags = 0, SV *callback = &PL_sv_undef) |
214 | |
209 | |
215 | $db = db_create (DB_ENV *env = 0, U32 flags = 0) |
210 | $db = db_create (DB_ENV *env = 0, U32 flags = 0) |
216 | flags: XA_CREATE |
211 | flags: XA_CREATE |
217 | |
212 | |
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) |
213 | 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) |
… | |
… | |
224 | flags: FREELIST_ONLY FREE_SPACE |
219 | flags: FREELIST_ONLY FREE_SPACE |
225 | db_sync (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) |
220 | db_sync (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) |
226 | 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 = &PL_sv_undef) |
227 | 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 = &PL_sv_undef) |
228 | flags: APPEND NODUPDATA NOOVERWRITE |
223 | flags: APPEND NODUPDATA NOOVERWRITE |
229 | db_exists (DB *db, DB_TXN_ornull *txn, SV *key, U32 flags = 0, SV *callback = 0) |
224 | db_exists (DB *db, DB_TXN_ornull *txn, SV *key, U32 flags = 0, SV *callback = 0) (v4.6) |
230 | 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 = &PL_sv_undef) |
231 | 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 |
232 | 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 = &PL_sv_undef) |
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_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 = &PL_sv_undef) |
… | |
… | |
251 | 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 = &PL_sv_undef) |
252 | flags: TXN_NOSYNC |
247 | flags: TXN_NOSYNC |
253 | 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 = &PL_sv_undef) |
254 | flags: TXN_NOSYNC |
249 | flags: TXN_NOSYNC |
255 | |
250 | |
256 | =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 = &PL_sv_undef) |
257 | |
252 | |
258 | This is not actually a Berkeley DB function but a BDB module |
253 | This is not actually a Berkeley DB function but a BDB module |
259 | extension. The background for this exytension is: It is very annoying to |
254 | extension. The background for this exytension is: It is very annoying to |
260 | have to check every single BDB function for error returns and provide a |
255 | have to check every single BDB function for error returns and provide a |
261 | codepath out of your transaction. While the BDB module still makes this |
256 | codepath out of your transaction. While the BDB module still makes this |
… | |
… | |
287 | |
282 | |
288 | You can use the C<< $txn->failed >> method to check wether a transaction |
283 | You can use the C<< $txn->failed >> method to check wether a transaction |
289 | has failed in this way and abort further processing (excluding |
284 | has failed in this way and abort further processing (excluding |
290 | C<db_txn_finish>). |
285 | C<db_txn_finish>). |
291 | |
286 | |
|
|
287 | |
292 | =head3 DB_ENV/database environment methods |
288 | =head2 DB_ENV/database environment methods |
293 | |
289 | |
294 | Methods available on DB_ENV/$env handles: |
290 | Methods available on DB_ENV/$env handles: |
295 | |
291 | |
296 | DESTROY (DB_ENV_ornull *env) |
292 | DESTROY (DB_ENV_ornull *env) |
297 | CODE: |
293 | CODE: |
… | |
… | |
302 | $int = $env->set_tmp_dir (const char *dir) |
298 | $int = $env->set_tmp_dir (const char *dir) |
303 | $int = $env->set_lg_dir (const char *dir) |
299 | $int = $env->set_lg_dir (const char *dir) |
304 | $int = $env->set_shm_key (long shm_key) |
300 | $int = $env->set_shm_key (long shm_key) |
305 | $int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0) |
301 | $int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0) |
306 | $int = $env->set_flags (U32 flags, int onoff = 1) |
302 | $int = $env->set_flags (U32 flags, int onoff = 1) |
307 | $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) |
308 | $int = $env->set_intermediate_dir_mode (const char *modestring) [v4.7] |
304 | $int = $env->set_intermediate_dir_mode (const char *modestring) (v4.7) |
309 | $env->set_errfile (FILE *errfile = 0) |
305 | $env->set_errfile (FILE *errfile = 0) |
310 | $env->set_msgfile (FILE *msgfile = 0) |
306 | $env->set_msgfile (FILE *msgfile = 0) |
311 | $int = $env->set_verbose (U32 which, int onoff = 1) |
307 | $int = $env->set_verbose (U32 which, int onoff = 1) |
312 | $int = $env->set_encrypt (const char *password, U32 flags = 0) |
308 | $int = $env->set_encrypt (const char *password, U32 flags = 0) |
313 | $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) |
… | |
… | |
325 | $int = $env->mutex_set_max (U32 max) |
321 | $int = $env->mutex_set_max (U32 max) |
326 | $int = $env->mutex_set_align (U32 align) |
322 | $int = $env->mutex_set_align (U32 align) |
327 | |
323 | |
328 | $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) |
329 | 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 |
330 | $txn = $env->cdsgroup_begin; |
326 | $txn = $env->cdsgroup_begin; (v4.5) |
331 | |
327 | |
332 | =head4 Example: |
328 | =head3 Example: |
333 | |
329 | |
334 | use AnyEvent; |
330 | use AnyEvent; |
335 | use BDB; |
331 | use BDB; |
336 | |
332 | |
337 | our $FH; open $FH, "<&=" . BDB::poll_fileno; |
333 | our $FH; open $FH, "<&=" . BDB::poll_fileno; |
… | |
… | |
349 | 0600; |
345 | 0600; |
350 | |
346 | |
351 | $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1); |
347 | $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1); |
352 | |
348 | |
353 | |
349 | |
354 | =head3 DB/database methods |
350 | =head2 DB/database methods |
355 | |
351 | |
356 | Methods available on DB/$db handles: |
352 | Methods available on DB/$db handles: |
357 | |
353 | |
358 | DESTROY (DB_ornull *db) |
354 | DESTROY (DB_ornull *db) |
359 | CODE: |
355 | CODE: |
… | |
… | |
385 | |
381 | |
386 | $dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0) |
382 | $dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0) |
387 | flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT |
383 | flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT |
388 | $seq = $db->sequence (U32 flags = 0) |
384 | $seq = $db->sequence (U32 flags = 0) |
389 | |
385 | |
390 | =head4 Example: |
386 | =head3 Example: |
391 | |
387 | |
392 | my $db = db_create $env; |
388 | my $db = db_create $env; |
393 | 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; |
394 | |
390 | |
395 | for (1..1000) { |
391 | for (1..1000) { |
… | |
… | |
402 | db_del $db, undef, "key $_" for 1..1000; |
398 | db_del $db, undef, "key $_" for 1..1000; |
403 | |
399 | |
404 | db_sync $db; |
400 | db_sync $db; |
405 | |
401 | |
406 | |
402 | |
407 | =head3 DB_TXN/transaction methods |
403 | =head2 DB_TXN/transaction methods |
408 | |
404 | |
409 | Methods available on DB_TXN/$txn handles: |
405 | Methods available on DB_TXN/$txn handles: |
410 | |
406 | |
411 | DESTROY (DB_TXN_ornull *txn) |
407 | DESTROY (DB_TXN_ornull *txn) |
412 | CODE: |
408 | CODE: |
… | |
… | |
418 | |
414 | |
419 | $bool = $txn->failed |
415 | $bool = $txn->failed |
420 | # see db_txn_finish documentation, above |
416 | # see db_txn_finish documentation, above |
421 | |
417 | |
422 | |
418 | |
423 | =head3 DBC/cursor methods |
419 | =head2 DBC/cursor methods |
424 | |
420 | |
425 | Methods available on DBC/$dbc handles: |
421 | Methods available on DBC/$dbc handles: |
426 | |
422 | |
427 | DESTROY (DBC_ornull *dbc) |
423 | DESTROY (DBC_ornull *dbc) |
428 | CODE: |
424 | CODE: |
429 | if (dbc) |
425 | if (dbc) |
430 | dbc->c_close (dbc); |
426 | dbc->c_close (dbc); |
431 | |
427 | |
432 | $int = $cursor->set_priority ($priority = PRIORITY_*) |
428 | $int = $cursor->set_priority ($priority = PRIORITY_*) (v4.6) |
433 | |
429 | |
434 | =head4 Example: |
430 | =head3 Example: |
435 | |
431 | |
436 | my $c = $db->cursor; |
432 | my $c = $db->cursor; |
437 | |
433 | |
438 | for (;;) { |
434 | for (;;) { |
439 | db_c_get $c, my $key, my $data, BDB::NEXT; |
435 | db_c_get $c, my $key, my $data, BDB::NEXT; |
… | |
… | |
442 | } |
438 | } |
443 | |
439 | |
444 | db_c_close $c; |
440 | db_c_close $c; |
445 | |
441 | |
446 | |
442 | |
447 | =head3 DB_SEQUENCE/sequence methods |
443 | =head2 DB_SEQUENCE/sequence methods |
448 | |
444 | |
449 | Methods available on DB_SEQUENCE/$seq handles: |
445 | Methods available on DB_SEQUENCE/$seq handles: |
450 | |
446 | |
451 | DESTROY (DB_SEQUENCE_ornull *seq) |
447 | DESTROY (DB_SEQUENCE_ornull *seq) |
452 | CODE: |
448 | CODE: |
… | |
… | |
457 | $int = $seq->set_cachesize (U32 size) |
453 | $int = $seq->set_cachesize (U32 size) |
458 | $int = $seq->set_flags (U32 flags) |
454 | $int = $seq->set_flags (U32 flags) |
459 | flags: SEQ_DEC SEQ_INC SEQ_WRAP |
455 | flags: SEQ_DEC SEQ_INC SEQ_WRAP |
460 | $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) |
461 | |
457 | |
462 | =head4 Example: |
458 | =head3 Example: |
463 | |
459 | |
464 | my $seq = $db->sequence; |
460 | my $seq = $db->sequence; |
465 | |
461 | |
466 | db_sequence_open $seq, undef, "seq", BDB::CREATE; |
462 | db_sequence_open $seq, undef, "seq", BDB::CREATE; |
467 | db_sequence_get $seq, undef, 1, my $value; |
463 | db_sequence_get $seq, undef, 1, my $value; |
468 | |
464 | |
469 | |
465 | |
470 | =head2 SUPPORT FUNCTIONS |
466 | =head1 SUPPORT FUNCTIONS |
471 | |
467 | |
472 | =head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION |
468 | =head2 EVENT PROCESSING AND EVENT LOOP INTEGRATION |
473 | |
469 | |
474 | =over 4 |
470 | =over 4 |
475 | |
471 | |
476 | =item $msg = BDB::strerror [$errno] |
472 | =item $msg = BDB::strerror [$errno] |
477 | |
473 | |
… | |
… | |
564 | BDB::poll_wait, BDB::poll_cb |
560 | BDB::poll_wait, BDB::poll_cb |
565 | while BDB::nreqs; |
561 | while BDB::nreqs; |
566 | |
562 | |
567 | =back |
563 | =back |
568 | |
564 | |
569 | =head3 VERSION CHECKING |
565 | =head2 VERSION CHECKING |
570 | |
566 | |
571 | BerkeleyDB comes in various versions, many of them have minor |
567 | BerkeleyDB comes in various versions, many of them have minor |
572 | incompatibilities. This means that traditional "at least version x.x" |
568 | incompatibilities. This means that traditional "at least version x.x" |
573 | checks are often not sufficient. |
569 | checks are often not sufficient. |
574 | |
570 | |
575 | Example: set the log_autoremove option in a way compatible with <v.47 and |
571 | Example: set the log_autoremove option in a way compatible with <v4.7 and |
576 | v4.7. Note the use of & on the constants to avoid triggering a compiletime |
572 | v4.7. Note the use of & on the constants to avoid triggering a compiletime |
577 | bug when the symbol isn't available. |
573 | bug when the symbol isn't available. |
578 | |
574 | |
579 | $DB_ENV->set_flags (&BDB::LOG_AUTOREMOVE ) if BDB::VERSION v0, v4.7; |
575 | $DB_ENV->set_flags (&BDB::LOG_AUTOREMOVE ) if BDB::VERSION v0, v4.7; |
580 | $DB_ENV->log_set_config (&BDB::LOG_AUTO_REMOVE) if BDB::VERSION v4.7; |
576 | $DB_ENV->log_set_config (&BDB::LOG_AUTO_REMOVE) if BDB::VERSION v4.7; |
… | |
… | |
613 | =back |
609 | =back |
614 | |
610 | |
615 | =cut |
611 | =cut |
616 | |
612 | |
617 | sub VERSION { |
613 | sub VERSION { |
|
|
614 | # I was dumb enough to override the VERSION method here, so let's try |
|
|
615 | # to fix it up. |
|
|
616 | |
|
|
617 | if ($_[0] eq __PACKAGE__) { |
|
|
618 | $VERSION |
|
|
619 | } else { |
618 | if (@_ > 0) { |
620 | if (@_ > 0) { |
619 | return undef if VERSION_v lt $_[0]; |
621 | return undef if VERSION_v lt $_[0]; |
620 | if (@_ > 1) { |
622 | if (@_ > 1) { |
621 | return undef if VERSION_v ge $_[1]; |
623 | return undef if VERSION_v ge $_[1]; |
|
|
624 | } |
622 | } |
625 | } |
|
|
626 | |
|
|
627 | VERSION_v |
623 | } |
628 | } |
624 | |
|
|
625 | VERSION_v |
|
|
626 | } |
629 | } |
627 | |
630 | |
628 | =head3 CONTROLLING THE NUMBER OF THREADS |
631 | =head2 CONTROLLING THE NUMBER OF THREADS |
629 | |
632 | |
630 | =over 4 |
633 | =over 4 |
631 | |
634 | |
632 | =item BDB::min_parallel $nthreads |
635 | =item BDB::min_parallel $nthreads |
633 | |
636 | |
… | |
… | |
694 | |
697 | |
695 | You can still queue as many requests as you want. Therefore, |
698 | You can still queue as many requests as you want. Therefore, |
696 | C<max_oustsanding> is mainly useful in simple scripts (with low values) or |
699 | C<max_oustsanding> is mainly useful in simple scripts (with low values) or |
697 | as a stop gap to shield against fatal memory overflow (with large values). |
700 | as a stop gap to shield against fatal memory overflow (with large values). |
698 | |
701 | |
699 | =item BDB::set_sync_prepare $cb |
702 | =item $old_cb = BDB::set_sync_prepare $cb |
700 | |
703 | |
701 | Sets a callback that is called whenever a request is created without an |
704 | Sets a callback that is called whenever a request is created without an |
702 | explicit callback. It has to return two code references. The first is used |
705 | explicit callback. It has to return two code references. The first is used |
703 | as the request callback (it should save the return status), and the second |
706 | as the request callback (it should save the return status), and the second |
704 | is called to wait until the first callback has been called (it must set |
707 | is called to wait until the first callback has been called (it must set |
705 | C<$!> to the return status). |
708 | C<$!> to the return status). |
706 | |
709 | |
707 | This mechanism can be used to include BDB into other event mechanisms, |
710 | This mechanism can be used to include BDB into other event mechanisms, |
708 | such as L<AnyEvent::BDB> or L<Coro::BDB>. |
711 | such as L<Coro::BDB>. |
709 | |
712 | |
710 | The default implementation works like this: |
713 | To allow other, callback-based, events to be executed while callback-less |
|
|
714 | ones are run, you could use this sync prepare function: |
711 | |
715 | |
712 | sub { |
716 | sub { |
713 | my $status; |
717 | my $status; |
714 | ( |
718 | ( |
715 | sub { $status = $! }, |
719 | sub { $status = $! }, |
716 | sub { BDB::poll while !defined $status; $! = $status }, |
720 | sub { BDB::poll while !defined $status; $! = $status }, |
717 | ) |
721 | ) |
718 | } |
722 | } |
719 | |
723 | |
720 | It simply blocks the process till the request has finished and then sets |
724 | It works by polling for results till the request has finished and then |
721 | C<$!> to the return value. This means that if you don't use a callback, |
725 | sets C<$!> to the return value. This means that if you don't use a |
722 | BDB will simply fall back to synchronous operations. |
726 | callback, BDB would simply fall back to synchronous operations. |
|
|
727 | |
|
|
728 | By default, or if the sync prepare function is set to C<undef>, is to |
|
|
729 | execute callback-less BDB requests in the foreground thread, setting C<$!> |
|
|
730 | to the return value, without polling for other events. |
723 | |
731 | |
724 | =back |
732 | =back |
725 | |
733 | |
726 | =head3 STATISTICAL INFORMATION |
734 | =head2 STATISTICAL INFORMATION |
727 | |
735 | |
728 | =over 4 |
736 | =over 4 |
729 | |
737 | |
730 | =item BDB::nreqs |
738 | =item BDB::nreqs |
731 | |
739 | |
… | |
… | |
749 | |
757 | |
750 | =back |
758 | =back |
751 | |
759 | |
752 | =cut |
760 | =cut |
753 | |
761 | |
754 | set_sync_prepare { |
762 | set_sync_prepare (undef); |
755 | my $status; |
|
|
756 | ( |
|
|
757 | sub { |
|
|
758 | $status = $!; |
|
|
759 | }, |
|
|
760 | sub { |
|
|
761 | BDB::poll while !defined $status; |
|
|
762 | $! = $status; |
|
|
763 | }, |
|
|
764 | ) |
|
|
765 | }; |
|
|
766 | |
763 | |
767 | min_parallel 8; |
764 | min_parallel 8; |
768 | |
765 | |
769 | END { flush } |
766 | END { flush } |
770 | |
767 | |
771 | 1; |
768 | 1; |
772 | |
769 | |
|
|
770 | =head1 COMMON PITFALLS |
|
|
771 | |
|
|
772 | =head2 Unexpected Crashes |
|
|
773 | |
|
|
774 | Remember that, by default, BDB will execute requests in parallel, in |
|
|
775 | somewhat random order. That means that it is easy to run a C<db_get> |
|
|
776 | request on thesa me database as a concurrent C<db_close> request, leading |
|
|
777 | to a crash, silent data corruption, eventually the next world war on |
|
|
778 | terrorism. |
|
|
779 | |
|
|
780 | If you only ever use foreground requests (without a callback), this will |
|
|
781 | not be an issue. |
|
|
782 | |
|
|
783 | =head2 Unexpected Freezes or Deadlocks |
|
|
784 | |
|
|
785 | Remember that, by default, BDB will execute requests in parallel, which |
|
|
786 | easily leads to deadlocks (even concurrent put's on the same database can |
|
|
787 | deadlock). |
|
|
788 | |
|
|
789 | You either need to run deadlock detection (and handle the resulting |
|
|
790 | errors), or make sure only one process ever updates the database, ine one |
|
|
791 | thread, e.g. by using only foreground requests (without a callback). |
|
|
792 | |
773 | =head2 FORK BEHAVIOUR |
793 | =head1 FORK BEHAVIOUR |
774 | |
794 | |
775 | This module should do "the right thing" when the process using it forks: |
795 | This module should do "the right thing" when the process using it forks: |
776 | |
796 | |
777 | Before the fork, BDB enters a quiescent state where no requests |
797 | Before the fork, BDB enters a quiescent state where no requests |
778 | can be added in other threads and no results will be processed. After |
798 | can be added in other threads and no results will be processed. After |
… | |
… | |
788 | |
808 | |
789 | Win32 note: there is no fork on win32, and perls emulation of it is too |
809 | Win32 note: there is no fork on win32, and perls emulation of it is too |
790 | broken to be supported, so do not use BDB in a windows pseudo-fork, better |
810 | broken to be supported, so do not use BDB in a windows pseudo-fork, better |
791 | yet, switch to a more capable platform. |
811 | yet, switch to a more capable platform. |
792 | |
812 | |
793 | =head2 MEMORY USAGE |
813 | =head1 MEMORY USAGE |
794 | |
814 | |
795 | Per-request usage: |
815 | Per-request usage: |
796 | |
816 | |
797 | Each aio request uses - depending on your architecture - around 100-200 |
817 | Each aio request uses - depending on your architecture - around 100-200 |
798 | bytes of memory. In addition, stat requests need a stat buffer (possibly |
818 | bytes of memory. In addition, stat requests need a stat buffer (possibly |
… | |
… | |
807 | |
827 | |
808 | In the execution phase, some aio requests require more memory for |
828 | In the execution phase, some aio requests require more memory for |
809 | temporary buffers, and each thread requires a stack and other data |
829 | temporary buffers, and each thread requires a stack and other data |
810 | structures (usually around 16k-128k, depending on the OS). |
830 | structures (usually around 16k-128k, depending on the OS). |
811 | |
831 | |
|
|
832 | =head1 WIN32 FILENAMES/DATABASE NAME MESS |
|
|
833 | |
|
|
834 | Perl on Win32 supports only ASCII filenames (the reason is that it abuses |
|
|
835 | an internal flag to store wether a filename is Unicode or ANSI, but that |
|
|
836 | flag is used for somethign else in the perl core, so there is no way to |
|
|
837 | detect wether a filename is ANSI or Unicode-encoded). The BDB module |
|
|
838 | tries to work around this issue by assuming that the filename is an ANSI |
|
|
839 | filename and BDB was built for unicode support. |
|
|
840 | |
812 | =head1 KNOWN BUGS |
841 | =head1 KNOWN BUGS |
813 | |
842 | |
814 | Known bugs will be fixed in the next release, except: |
843 | Known bugs will be fixed in the next release, except: |
815 | |
844 | |
816 | 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 |