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Comparing BDB/BDB.pm (file contents):
Revision 1.35 by root, Sun Mar 30 08:01:58 2008 UTC vs.
Revision 1.60 by root, Fri Dec 4 15:04:06 2009 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 result processing with AnyEvent: 32 # automatic event loop integration with AnyEvent:
33 our $FH; open $FH, "<&=" . BDB::poll_fileno; 33 use AnyEvent::BDB;
34 our $WATCHER = AnyEvent->io (fh => $FH, poll => 'r', cb => \&BDB::poll_cb);
35 34
36 # automatic result processing with EV: 35 # automatic result processing with EV:
37 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;
38 37
39 # with Glib: 38 # with Glib:
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104 103
105=cut 104=cut
106 105
107package BDB; 106package BDB;
108 107
109no warnings; 108use common::sense;
110use strict 'vars';
111 109
112use base 'Exporter'; 110use base 'Exporter';
113 111
112our $VERSION;
113
114BEGIN { 114BEGIN {
115 our $VERSION = '1.45'; 115 $VERSION = '1.86';
116 116
117 our @BDB_REQ = qw( 117 our @BDB_REQ = qw(
118 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
119 db_env_memp_sync db_env_memp_trickle 119 db_env_memp_sync db_env_memp_trickle db_env_dbrename db_env_dbremove
120 db_env_log_archive
120 db_open db_close db_compact db_sync db_upgrade 121 db_open db_close db_compact db_sync db_verify db_upgrade
121 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
122 db_txn_commit db_txn_abort db_txn_finish 123 db_txn_commit db_txn_abort db_txn_finish
123 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
124 db_sequence_open db_sequence_close 125 db_sequence_open db_sequence_close
125 db_sequence_get db_sequence_remove 126 db_sequence_get db_sequence_remove
126 ); 127 );
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134 135
135 require XSLoader; 136 require XSLoader;
136 XSLoader::load ("BDB", $VERSION); 137 XSLoader::load ("BDB", $VERSION);
137} 138}
138 139
139=head2 WIN32 FILENAMES/DATABASE NAME MESS
140
141Perl on Win32 supports only ASCII filenames (the reason is that it abuses
142an internal flag to store wether a filename is Unicode or ANSI, but that
143flag is used for somethign else in the perl core, so there is no way to
144detect wether a filename is ANSI or Unicode-encoded). The BDB module
145tries to work around this issue by assuming that the filename is an ANSI
146filename and BDB was built for unicode support.
147
148=head2 BERKELEYDB FUNCTIONS 140=head1 BERKELEYDB FUNCTIONS
149 141
150All of these are functions. The create functions simply return a new 142All of these are functions. The create functions simply return a new
151object and never block. All the remaining functions take an optional 143object and never block. All the remaining functions take an optional
152callback as last argument. If it is missing, then the function will be 144callback as last argument. If it is missing, then the function will be
153executed synchronously. In both cases, C<$!> will reflect the return value 145executed synchronously. In both cases, C<$!> will reflect the return value
… …
157settings) are method calls on the relevant objects, so the rule of thumb 149settings) are method calls on the relevant objects, so the rule of thumb
158is: if it's a method, it's not blocking, if it's a function, it takes a 150is: if it's a method, it's not blocking, if it's a function, it takes a
159callback as last argument. 151callback as last argument.
160 152
161In the following, C<$int> signifies an integer return value, 153In the following, C<$int> signifies an integer return value,
162C<octetstring> is a "binary string" (i.e. a perl string with no character 154C<bdb_filename> is a "filename" (octets on unix, madness on windows),
163indices >255), C<U32> is an unsigned 32 bit integer, C<int> is some 155C<U32> is an unsigned 32 bit integer, C<int> is some integer, C<NV> is a
164integer, C<NV> is a floating point value. 156floating point value.
165 157
166The C<SV *> types are generic perl scalars (for input and output of data 158Most C<SV *> types are generic perl scalars (for input and output of data
167values), and the C<SV *callback> is the optional callback function to call 159values).
168when the request is completed.
169 160
170The various C<DB_ENV> etc. arguments are handles return by 161The various C<DB_ENV> etc. arguments are handles return by
171C<db_env_create>, C<db_create>, C<txn_begin> and so on. If they have an 162C<db_env_create>, C<db_create>, C<txn_begin> and so on. If they have an
172appended C<_ornull> this means they are optional and you can pass C<undef> 163appended C<_ornull> this means they are optional and you can pass C<undef>
173for them, resulting a NULL pointer on the C level. 164for them, resulting a NULL pointer on the C level.
174 165
166The C<SV *callback> is the optional callback function to call when the
167request is completed. This last callback argument is special: the callback
168is simply the last argument passed. If there are "optional" arguments
169before the callback they can be left out. The callback itself can be left
170out or specified as C<undef>, in which case the function will be executed
171synchronously.
172
173For example, C<db_env_txn_checkpoint> usually is called with all integer
174arguments zero. These can be left out, so all of these specify a call
175to C<< DB_ENV->txn_checkpoint >>, to be executed asynchronously with a
176callback to be called:
177
178 db_env_txn_checkpoint $db_env, 0, 0, 0, sub { };
179 db_env_txn_checkpoint $db_env, 0, 0, sub { };
180 db_env_txn_checkpoint $db_env, sub { };
181
182While these all specify a call to C<< DB_ENV->txn_checkpoint >> to be
183executed synchronously:
184
185 db_env_txn_checkpoint $db_env, 0, 0, 0, undef;
186 db_env_txn_checkpoint $db_env, 0, 0, 0;
187 db_env_txn_checkpoint $db_env, 0;
188
175=head3 BDB functions 189=head2 BDB functions
176 190
177Functions in the BDB namespace, exported by default: 191Functions in the BDB namespace, exported by default:
178 192
179 $env = db_env_create (U32 env_flags = 0) 193 $env = db_env_create (U32 env_flags = 0)
180 flags: RPCCLIENT 194 flags: RPCCLIENT
181 195
182 db_env_open (DB_ENV *env, octetstring 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)
183 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
184 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)
185 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)
186 flags: FORCE 200 flags: FORCE
187 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)
188 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
189 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)
190 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)
205 db_env_dbremove (DB_ENV *env, DB_TXN_ornull *txnid, bdb_filename file, bdb_filename database, U32 flags = 0, SV *callback = 0)
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)
191 208
192 $db = db_create (DB_ENV *env = 0, U32 flags = 0) 209 $db = db_create (DB_ENV *env = 0, U32 flags = 0)
193 flags: XA_CREATE 210 flags: XA_CREATE
194 211
195 db_open (DB *db, DB_TXN_ornull *txnid, octetstring file, octetstring database, int type, U32 flags, int mode, SV *callback = &PL_sv_undef) 212 db_open (DB *db, DB_TXN_ornull *txnid, bdb_filename file, bdb_filename database, int type, U32 flags, int mode, SV *callback = 0)
196 flags: AUTO_COMMIT CREATE EXCL MULTIVERSION NOMMAP RDONLY READ_UNCOMMITTED THREAD TRUNCATE 213 flags: AUTO_COMMIT CREATE EXCL MULTIVERSION NOMMAP RDONLY READ_UNCOMMITTED THREAD TRUNCATE
197 db_close (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) 214 db_close (DB *db, U32 flags = 0, SV *callback = 0)
198 flags: DB_NOSYNC 215 flags: DB_NOSYNC
216 db_verify (DB *db, bdb_filename file, bdb_filename database = 0, SV *dummy = 0, U32 flags = 0, SV *callback = 0)
199 db_upgrade (DB *db, octetstring file, U32 flags = 0, SV *callback = &PL_sv_undef) 217 db_upgrade (DB *db, bdb_filename file, U32 flags = 0, SV *callback = 0)
200 db_compact (DB *db, DB_TXN_ornull *txn = 0, SV *start = 0, SV *stop = 0, SV *unused1 = 0, U32 flags = DB_FREE_SPACE, SV *unused2 = 0, SV *callback = &PL_sv_undef) 218 db_compact (DB *db, DB_TXN_ornull *txn = 0, SV *start = 0, SV *stop = 0, SV *unused1 = 0, U32 flags = DB_FREE_SPACE, SV *unused2 = 0, SV *callback = 0)
201 flags: FREELIST_ONLY FREE_SPACE 219 flags: FREELIST_ONLY FREE_SPACE
202 db_sync (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) 220 db_sync (DB *db, U32 flags = 0, SV *callback = 0)
203 db_key_range (DB *db, DB_TXN_ornull *txn, SV *key, SV *key_range, U32 flags = 0, SV *callback = &PL_sv_undef) 221 db_key_range (DB *db, DB_TXN_ornull *txn, SV *key, SV *key_range, U32 flags = 0, SV *callback = 0)
204 db_put (DB *db, DB_TXN_ornull *txn, SV *key, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) 222 db_put (DB *db, DB_TXN_ornull *txn, SV *key, SV *data, U32 flags = 0, SV *callback = 0)
205 flags: APPEND NODUPDATA NOOVERWRITE 223 flags: APPEND NODUPDATA NOOVERWRITE
224 db_exists (DB *db, DB_TXN_ornull *txn, SV *key, U32 flags = 0, SV *callback = 0) (v4.6)
206 db_get (DB *db, DB_TXN_ornull *txn, SV *key, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) 225 db_get (DB *db, DB_TXN_ornull *txn, SV *key, SV *data, U32 flags = 0, SV *callback = 0)
207 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
208 db_pget (DB *db, DB_TXN_ornull *txn, SV *key, SV *pkey, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) 227 db_pget (DB *db, DB_TXN_ornull *txn, SV *key, SV *pkey, SV *data, U32 flags = 0, SV *callback = 0)
209 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
210 db_del (DB *db, DB_TXN_ornull *txn, SV *key, U32 flags = 0, SV *callback = &PL_sv_undef) 229 db_del (DB *db, DB_TXN_ornull *txn, SV *key, U32 flags = 0, SV *callback = 0)
211 db_txn_commit (DB_TXN *txn, U32 flags = 0, SV *callback = &PL_sv_undef) 230 db_txn_commit (DB_TXN *txn, U32 flags = 0, SV *callback = 0)
212 flags: TXN_NOSYNC TXN_SYNC 231 flags: TXN_NOSYNC TXN_SYNC
213 db_txn_abort (DB_TXN *txn, SV *callback = &PL_sv_undef) 232 db_txn_abort (DB_TXN *txn, SV *callback = 0)
214 233
215 db_c_close (DBC *dbc, SV *callback = &PL_sv_undef) 234 db_c_close (DBC *dbc, SV *callback = 0)
216 db_c_count (DBC *dbc, SV *count, U32 flags = 0, SV *callback = &PL_sv_undef) 235 db_c_count (DBC *dbc, SV *count, U32 flags = 0, SV *callback = 0)
217 db_c_put (DBC *dbc, SV *key, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) 236 db_c_put (DBC *dbc, SV *key, SV *data, U32 flags = 0, SV *callback = 0)
218 flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA 237 flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA
219 db_c_get (DBC *dbc, SV *key, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) 238 db_c_get (DBC *dbc, SV *key, SV *data, U32 flags = 0, SV *callback = 0)
220 flags: CURRENT FIRST GET_BOTH GET_BOTH_RANGE GET_RECNO JOIN_ITEM LAST NEXT NEXT_DUP NEXT_NODUP PREV PREV_DUP PREV_NODUP SET SET_RANGE SET_RECNO READ_UNCOMMITTED MULTIPLE MULTIPLE_KEY RMW 239 flags: CURRENT FIRST GET_BOTH GET_BOTH_RANGE GET_RECNO JOIN_ITEM LAST NEXT NEXT_DUP NEXT_NODUP PREV PREV_DUP PREV_NODUP SET SET_RANGE SET_RECNO READ_UNCOMMITTED MULTIPLE MULTIPLE_KEY RMW
221 db_c_pget (DBC *dbc, SV *key, SV *pkey, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) 240 db_c_pget (DBC *dbc, SV *key, SV *pkey, SV *data, U32 flags = 0, SV *callback = 0)
222 db_c_del (DBC *dbc, U32 flags = 0, SV *callback = &PL_sv_undef) 241 db_c_del (DBC *dbc, U32 flags = 0, SV *callback = 0)
223 242
224 db_sequence_open (DB_SEQUENCE *seq, DB_TXN_ornull *txnid, SV *key, U32 flags = 0, SV *callback = &PL_sv_undef) 243 db_sequence_open (DB_SEQUENCE *seq, DB_TXN_ornull *txnid, SV *key, U32 flags = 0, SV *callback = 0)
225 flags: CREATE EXCL 244 flags: CREATE EXCL
226 db_sequence_close (DB_SEQUENCE *seq, U32 flags = 0, SV *callback = &PL_sv_undef) 245 db_sequence_close (DB_SEQUENCE *seq, U32 flags = 0, SV *callback = 0)
227 db_sequence_get (DB_SEQUENCE *seq, DB_TXN_ornull *txnid, int delta, SV *seq_value, U32 flags = DB_TXN_NOSYNC, SV *callback = &PL_sv_undef) 246 db_sequence_get (DB_SEQUENCE *seq, DB_TXN_ornull *txnid, int delta, SV *seq_value, U32 flags = DB_TXN_NOSYNC, SV *callback = 0)
228 flags: TXN_NOSYNC 247 flags: TXN_NOSYNC
229 db_sequence_remove (DB_SEQUENCE *seq, DB_TXN_ornull *txnid = 0, U32 flags = 0, SV *callback = &PL_sv_undef) 248 db_sequence_remove (DB_SEQUENCE *seq, DB_TXN_ornull *txnid = 0, U32 flags = 0, SV *callback = 0)
230 flags: TXN_NOSYNC 249 flags: TXN_NOSYNC
231 250
232=head4 db_txn_finish (DB_TXN *txn, U32 flags = 0, SV *callback = &PL_sv_undef) 251=head3 db_txn_finish (DB_TXN *txn, U32 flags = 0, SV *callback = 0)
233 252
234This is not actually a Berkeley DB function but a BDB module 253This is not actually a Berkeley DB function but a BDB module
235extension. The background for this exytension is: It is very annoying to 254extension. The background for this exytension is: It is very annoying to
236have to check every single BDB function for error returns and provide a 255have to check every single BDB function for error returns and provide a
237codepath out of your transaction. While the BDB module still makes this 256codepath out of your transaction. While the BDB module still makes this
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263 282
264You can use the C<< $txn->failed >> method to check wether a transaction 283You can use the C<< $txn->failed >> method to check wether a transaction
265has failed in this way and abort further processing (excluding 284has failed in this way and abort further processing (excluding
266C<db_txn_finish>). 285C<db_txn_finish>).
267 286
287
268=head3 DB_ENV/database environment methods 288=head2 DB_ENV/database environment methods
269 289
270Methods available on DB_ENV/$env handles: 290Methods available on DB_ENV/$env handles:
271 291
272 DESTROY (DB_ENV_ornull *env) 292 DESTROY (DB_ENV_ornull *env)
273 CODE: 293 CODE:
… …
277 $int = $env->set_data_dir (const char *dir) 297 $int = $env->set_data_dir (const char *dir)
278 $int = $env->set_tmp_dir (const char *dir) 298 $int = $env->set_tmp_dir (const char *dir)
279 $int = $env->set_lg_dir (const char *dir) 299 $int = $env->set_lg_dir (const char *dir)
280 $int = $env->set_shm_key (long shm_key) 300 $int = $env->set_shm_key (long shm_key)
281 $int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0) 301 $int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0)
282 $int = $env->set_flags (U32 flags, int onoff) 302 $int = $env->set_flags (U32 flags, int onoff = 1)
303 $int = $env->log_set_config (U32 flags, int onoff = 1) (v4.7)
304 $int = $env->set_intermediate_dir_mode (const char *modestring) (v4.7)
283 $env->set_errfile (FILE *errfile = 0) 305 $env->set_errfile (FILE *errfile = 0)
284 $env->set_msgfile (FILE *msgfile = 0) 306 $env->set_msgfile (FILE *msgfile = 0)
285 $int = $env->set_verbose (U32 which, int onoff = 1) 307 $int = $env->set_verbose (U32 which, int onoff = 1)
286 $int = $env->set_encrypt (const char *password, U32 flags = 0) 308 $int = $env->set_encrypt (const char *password, U32 flags = 0)
287 $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)
… …
299 $int = $env->mutex_set_max (U32 max) 321 $int = $env->mutex_set_max (U32 max)
300 $int = $env->mutex_set_align (U32 align) 322 $int = $env->mutex_set_align (U32 align)
301 323
302 $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)
303 flags: READ_COMMITTED READ_UNCOMMITTED TXN_NOSYNC TXN_NOWAIT TXN_SNAPSHOT TXN_SYNC TXN_WAIT TXN_WRITE_NOSYNC 325 flags: READ_COMMITTED READ_UNCOMMITTED TXN_NOSYNC TXN_NOWAIT TXN_SNAPSHOT TXN_SYNC TXN_WAIT TXN_WRITE_NOSYNC
326 $txn = $env->cdsgroup_begin; (v4.5)
304 327
305=head4 Example: 328=head3 Example:
306 329
307 use AnyEvent; 330 use AnyEvent;
308 use BDB; 331 use BDB;
309 332
310 our $FH; open $FH, "<&=" . BDB::poll_fileno; 333 our $FH; open $FH, "<&=" . BDB::poll_fileno;
… …
322 0600; 345 0600;
323 346
324 $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1); 347 $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1);
325 348
326 349
327=head3 DB/database methods 350=head2 DB/database methods
328 351
329Methods available on DB/$db handles: 352Methods available on DB/$db handles:
330 353
331 DESTROY (DB_ornull *db) 354 DESTROY (DB_ornull *db)
332 CODE: 355 CODE:
… …
358 381
359 $dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0) 382 $dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0)
360 flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT 383 flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT
361 $seq = $db->sequence (U32 flags = 0) 384 $seq = $db->sequence (U32 flags = 0)
362 385
363=head4 Example: 386=head3 Example:
364 387
365 my $db = db_create $env; 388 my $db = db_create $env;
366 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;
367 390
368 for (1..1000) { 391 for (1..1000) {
… …
375 db_del $db, undef, "key $_" for 1..1000; 398 db_del $db, undef, "key $_" for 1..1000;
376 399
377 db_sync $db; 400 db_sync $db;
378 401
379 402
380=head3 DB_TXN/transaction methods 403=head2 DB_TXN/transaction methods
381 404
382Methods available on DB_TXN/$txn handles: 405Methods available on DB_TXN/$txn handles:
383 406
384 DESTROY (DB_TXN_ornull *txn) 407 DESTROY (DB_TXN_ornull *txn)
385 CODE: 408 CODE:
… …
391 414
392 $bool = $txn->failed 415 $bool = $txn->failed
393 # see db_txn_finish documentation, above 416 # see db_txn_finish documentation, above
394 417
395 418
396=head3 DBC/cursor methods 419=head2 DBC/cursor methods
397 420
398Methods available on DBC/$dbc handles: 421Methods available on DBC/$dbc handles:
399 422
400 DESTROY (DBC_ornull *dbc) 423 DESTROY (DBC_ornull *dbc)
401 CODE: 424 CODE:
402 if (dbc) 425 if (dbc)
403 dbc->c_close (dbc); 426 dbc->c_close (dbc);
404 427
405 $int = $cursor->set_priority ($priority = PRIORITY_*) 428 $int = $cursor->set_priority ($priority = PRIORITY_*) (v4.6)
406 429
407=head4 Example: 430=head3 Example:
408 431
409 my $c = $db->cursor; 432 my $c = $db->cursor;
410 433
411 for (;;) { 434 for (;;) {
412 db_c_get $c, my $key, my $data, BDB::NEXT; 435 db_c_get $c, my $key, my $data, BDB::NEXT;
… …
415 } 438 }
416 439
417 db_c_close $c; 440 db_c_close $c;
418 441
419 442
420=head3 DB_SEQUENCE/sequence methods 443=head2 DB_SEQUENCE/sequence methods
421 444
422Methods available on DB_SEQUENCE/$seq handles: 445Methods available on DB_SEQUENCE/$seq handles:
423 446
424 DESTROY (DB_SEQUENCE_ornull *seq) 447 DESTROY (DB_SEQUENCE_ornull *seq)
425 CODE: 448 CODE:
… …
430 $int = $seq->set_cachesize (U32 size) 453 $int = $seq->set_cachesize (U32 size)
431 $int = $seq->set_flags (U32 flags) 454 $int = $seq->set_flags (U32 flags)
432 flags: SEQ_DEC SEQ_INC SEQ_WRAP 455 flags: SEQ_DEC SEQ_INC SEQ_WRAP
433 $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)
434 457
435=head4 Example: 458=head3 Example:
436 459
437 my $seq = $db->sequence; 460 my $seq = $db->sequence;
438 461
439 db_sequence_open $seq, undef, "seq", BDB::CREATE; 462 db_sequence_open $seq, undef, "seq", BDB::CREATE;
440 db_sequence_get $seq, undef, 1, my $value; 463 db_sequence_get $seq, undef, 1, my $value;
441 464
442 465
443=head2 SUPPORT FUNCTIONS 466=head1 SUPPORT FUNCTIONS
444 467
445=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 468=head2 EVENT PROCESSING AND EVENT LOOP INTEGRATION
446 469
447=over 4 470=over 4
448 471
449=item $msg = BDB::strerror [$errno] 472=item $msg = BDB::strerror [$errno]
450 473
… …
537 BDB::poll_wait, BDB::poll_cb 560 BDB::poll_wait, BDB::poll_cb
538 while BDB::nreqs; 561 while BDB::nreqs;
539 562
540=back 563=back
541 564
565=head2 VERSION CHECKING
566
567BerkeleyDB comes in various versions, many of them have minor
568incompatibilities. This means that traditional "at least version x.x"
569checks are often not sufficient.
570
571Example: set the log_autoremove option in a way compatible with <v4.7 and
572v4.7. Note the use of & on the constants to avoid triggering a compiletime
573bug when the symbol isn't available.
574
575 $DB_ENV->set_flags (&BDB::LOG_AUTOREMOVE ) if BDB::VERSION v0, v4.7;
576 $DB_ENV->log_set_config (&BDB::LOG_AUTO_REMOVE) if BDB::VERSION v4.7;
577
578=over 4
579
580=item BDB::VERSION
581
582The C<BDB::VERSION> function, when called without arguments, returns the
583Berkeley DB version as a v-string (usually with 3 components). You should
584use C<lt> and C<ge> operators exclusively to make comparisons.
585
586Example: check for at least version 4.7.
587
588 BDB::VERSION ge v4.7 or die;
589
590=item BDB::VERSION min-version
591
592Returns true if the BDB version is at least the given version (specified
593as a v-string), false otherwise.
594
595Example: check for at least version 4.5.
596
597 BDB::VERSION v4.7 or die;
598
599=item BDB::VERSION min-version, max-version
600
601Returns true of the BDB version is at least version C<min-version> (specify C<undef> or C<v0> for any minimum version)
602and less then C<max-version>.
603
604Example: check wether version is strictly less then v4.7.
605
606 BDB::VERSION v0, v4.7
607 or die "version 4.7 is not yet supported";
608
609=back
610
611=cut
612
613sub VERSION {
614 # I was dumb enough to override the VERSION method here, so let's try
615 # to fix it up.
616
617 if ($_[0] eq __PACKAGE__) {
618 $VERSION
619 } else {
620 if (@_ > 0) {
621 return undef if VERSION_v lt $_[0];
622 if (@_ > 1) {
623 return undef if VERSION_v ge $_[1];
624 }
625 }
626
627 VERSION_v
628 }
629}
630
542=head3 CONTROLLING THE NUMBER OF THREADS 631=head2 CONTROLLING THE NUMBER OF THREADS
543 632
544=over 4 633=over 4
545 634
546=item BDB::min_parallel $nthreads 635=item BDB::min_parallel $nthreads
547 636
… …
608 697
609You can still queue as many requests as you want. Therefore, 698You can still queue as many requests as you want. Therefore,
610C<max_oustsanding> is mainly useful in simple scripts (with low values) or 699C<max_oustsanding> is mainly useful in simple scripts (with low values) or
611as a stop gap to shield against fatal memory overflow (with large values). 700as a stop gap to shield against fatal memory overflow (with large values).
612 701
613=item BDB::set_sync_prepare $cb 702=item $old_cb = BDB::set_sync_prepare $cb
614 703
615Sets a callback that is called whenever a request is created without an 704Sets a callback that is called whenever a request is created without an
616explicit callback. It has to return two code references. The first is used 705explicit callback. It has to return two code references. The first is used
617as the request callback, and the second is called to wait until the first 706as the request callback (it should save the return status), and the second
618callback has been called. The default implementation works like this: 707is called to wait until the first callback has been called (it must set
708C<$!> to the return status).
709
710This mechanism can be used to include BDB into other event mechanisms,
711such as L<Coro::BDB>.
712
713To allow other, callback-based, events to be executed while callback-less
714ones are run, you could use this sync prepare function:
619 715
620 sub { 716 sub {
621 my $status; 717 my $status;
622 ( 718 (
623 sub { $status = $! }, 719 sub { $status = $! },
624 sub { BDB::poll while !defined $status; $! = $status }, 720 sub { BDB::poll while !defined $status; $! = $status },
625 ) 721 )
626 } 722 }
627 723
724It works by polling for results till the request has finished and then
725sets C<$!> to the return value. This means that if you don't use a
726callback, BDB would simply fall back to synchronous operations.
727
728By default, or if the sync prepare function is set to C<undef>, is to
729execute callback-less BDB requests in the foreground thread, setting C<$!>
730to the return value, without polling for other events.
731
628=back 732=back
629 733
630=head3 STATISTICAL INFORMATION 734=head2 STATISTICAL INFORMATION
631 735
632=over 4 736=over 4
633 737
634=item BDB::nreqs 738=item BDB::nreqs
635 739
… …
653 757
654=back 758=back
655 759
656=cut 760=cut
657 761
658set_sync_prepare { 762set_sync_prepare (undef);
659 my $status;
660 (
661 sub {
662 $status = $!;
663 },
664 sub {
665 BDB::poll while !defined $status;
666 $! = $status;
667 },
668 )
669};
670 763
671min_parallel 8; 764min_parallel 8;
672 765
673END { flush } 766END { flush }
674 767
6751; 7681;
676 769
770=head1 COMMON PITFALLS
771
772=head2 Unexpected Crashes
773
774Remember that, by default, BDB will execute requests in parallel, in
775somewhat random order. That means that it is easy to run a C<db_get>
776request on thesa me database as a concurrent C<db_close> request, leading
777to a crash, silent data corruption, eventually the next world war on
778terrorism.
779
780If you only ever use foreground requests (without a callback), this will
781not be an issue.
782
783=head2 Unexpected Freezes or Deadlocks
784
785Remember that, by default, BDB will execute requests in parallel, which
786easily leads to deadlocks (even concurrent put's on the same database can
787deadlock).
788
789You either need to run deadlock detection (and handle the resulting
790errors), or make sure only one process ever updates the database, ine one
791thread, e.g. by using only foreground requests (without a callback).
792
677=head2 FORK BEHAVIOUR 793=head1 FORK BEHAVIOUR
678 794
679This module should do "the right thing" when the process using it forks: 795This module should do "the right thing" when the process using it forks:
680 796
681Before the fork, BDB enters a quiescent state where no requests 797Before the fork, BDB enters a quiescent state where no requests
682can be added in other threads and no results will be processed. After 798can be added in other threads and no results will be processed. After
… …
692 808
693Win32 note: there is no fork on win32, and perls emulation of it is too 809Win32 note: there is no fork on win32, and perls emulation of it is too
694broken to be supported, so do not use BDB in a windows pseudo-fork, better 810broken to be supported, so do not use BDB in a windows pseudo-fork, better
695yet, switch to a more capable platform. 811yet, switch to a more capable platform.
696 812
697=head2 MEMORY USAGE 813=head1 MEMORY USAGE
698 814
699Per-request usage: 815Per-request usage:
700 816
701Each aio request uses - depending on your architecture - around 100-200 817Each aio request uses - depending on your architecture - around 100-200
702bytes of memory. In addition, stat requests need a stat buffer (possibly 818bytes of memory. In addition, stat requests need a stat buffer (possibly
… …
711 827
712In the execution phase, some aio requests require more memory for 828In the execution phase, some aio requests require more memory for
713temporary buffers, and each thread requires a stack and other data 829temporary buffers, and each thread requires a stack and other data
714structures (usually around 16k-128k, depending on the OS). 830structures (usually around 16k-128k, depending on the OS).
715 831
832=head1 WIN32 FILENAMES/DATABASE NAME MESS
833
834Perl on Win32 supports only ASCII filenames (the reason is that it abuses
835an internal flag to store wether a filename is Unicode or ANSI, but that
836flag is used for somethign else in the perl core, so there is no way to
837detect wether a filename is ANSI or Unicode-encoded). The BDB module
838tries to work around this issue by assuming that the filename is an ANSI
839filename and BDB was built for unicode support.
840
716=head1 KNOWN BUGS 841=head1 KNOWN BUGS
717 842
718Known bugs will be fixed in the next release, except: 843Known bugs will be fixed in the next release, except:
719 844
720 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
… …
722 TXN_DEADLOCK flag will be set on the transaction. See C<db_txn_finish>, 847 TXN_DEADLOCK flag will be set on the transaction. See C<db_txn_finish>,
723 above. 848 above.
724 849
725=head1 SEE ALSO 850=head1 SEE ALSO
726 851
727L<Coro::BDB>, L<IO::AIO>. 852L<AnyEvent::BDB> (event loop integration), L<Coro::BDB> (more natural
853syntax), L<IO::AIO> (nice to have).
728 854
729=head1 AUTHOR 855=head1 AUTHOR
730 856
731 Marc Lehmann <schmorp@schmorp.de> 857 Marc Lehmann <schmorp@schmorp.de>
732 http://home.schmorp.de/ 858 http://home.schmorp.de/

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