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Comparing BDB/BDB.pm (file contents):
Revision 1.28 by root, Mon Dec 17 06:31:43 2007 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 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:
… …
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 = '1.4'; 115 $VERSION = '1.92';
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 db_env_lsn_reset db_env_fileid_reset
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 );
… …
134 135
135 require XSLoader; 136 require XSLoader;
136 XSLoader::load ("BDB", $VERSION); 137 XSLoader::load ("BDB", $VERSION);
137} 138}
138 139
139=head2 BERKELEYDB FUNCTIONS 140=head1 BERKELEYDB FUNCTIONS
140 141
141All of these are functions. The create functions simply return a new 142All of these are functions. The create functions simply return a new
142object and never block. All the remaining functions all take an optional 143object and never block. All the remaining functions take an optional
143callback as last argument. If it is missing, then the function will be 144callback as last argument. If it is missing, then the function will be
144executed synchronously. In both cases, C<$!> will reflect the return value 145executed synchronously. In both cases, C<$!> will reflect the return value
145of the function. 146of the function.
146 147
147BDB functions that cannot block (mostly functions that manipulate 148BDB functions that cannot block (mostly functions that manipulate
148settings) are method calls on the relevant objects, so the rule of thumb 149settings) are method calls on the relevant objects, so the rule of thumb
149is: if its a method, its not blocking, if its a function, it takes a 150is: if it's a method, it's not blocking, if it's a function, it takes a
150callback as last argument. 151callback as last argument.
151 152
152In the following, C<$int> signifies an integer return value, 153In the following, C<$int> signifies an integer return value,
153C<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),
154indices >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
155integer, C<NV> is a floating point value. 156floating point value.
156 157
157The 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
158values), and the C<SV *callback> is the optional callback function to call 159values).
159when the request is completed.
160 160
161The various C<DB_ENV> etc. arguments are handles return by 161The various C<DB_ENV> etc. arguments are handles return by
162C<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
163appended 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>
164for them, resulting a NULL pointer on the C level. 164for them, resulting a NULL pointer on the C level.
165 165
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
166=head3 BDB functions 189=head2 BDB functions
167 190
168Functions in the BDB namespace, exported by default: 191Functions in the BDB namespace, exported by default:
169 192
170 $env = db_env_create (U32 env_flags = 0) 193 $env = db_env_create (U32 env_flags = 0)
171 flags: RPCCLIENT 194 flags: RPCCLIENT
172 195
173 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)
174 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
175 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)
176 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)
177 flags: FORCE 200 flags: FORCE
178 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)
179 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
180 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)
181 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)
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)
182 210
183 $db = db_create (DB_ENV *env = 0, U32 flags = 0) 211 $db = db_create (DB_ENV *env = 0, U32 flags = 0)
184 flags: XA_CREATE 212 flags: XA_CREATE
185 213
186 db_open (DB *db, DB_TXN_ornull *txnid, octetstring file, octetstring 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)
187 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
188 db_close (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) 216 db_close (DB *db, U32 flags = 0, SV *callback = 0)
189 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)
190 db_upgrade (DB *db, octetstring file, U32 flags = 0, SV *callback = &PL_sv_undef) 219 db_upgrade (DB *db, bdb_filename file, U32 flags = 0, SV *callback = 0)
191 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)
192 flags: FREELIST_ONLY FREE_SPACE 221 flags: FREELIST_ONLY FREE_SPACE
193 db_sync (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) 222 db_sync (DB *db, U32 flags = 0, SV *callback = 0)
194 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)
195 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)
196 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)
197 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)
198 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
199 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)
200 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
201 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)
202 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)
203 flags: TXN_NOSYNC TXN_SYNC 233 flags: TXN_NOSYNC TXN_SYNC
204 db_txn_abort (DB_TXN *txn, SV *callback = &PL_sv_undef) 234 db_txn_abort (DB_TXN *txn, SV *callback = 0)
205 235
206 db_c_close (DBC *dbc, SV *callback = &PL_sv_undef) 236 db_c_close (DBC *dbc, SV *callback = 0)
207 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)
208 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)
209 flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA 239 flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA
210 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)
211 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
212 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)
213 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)
214 244
215 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)
216 flags: CREATE EXCL 246 flags: CREATE EXCL
217 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)
218 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)
219 flags: TXN_NOSYNC 249 flags: TXN_NOSYNC
220 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)
221 flags: TXN_NOSYNC 251 flags: TXN_NOSYNC
222 252
223=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)
224 254
225This is not actually a Berkeley DB function but a BDB module 255This is not actually a Berkeley DB function but a BDB module
226extension. The background for this exytension is: It is very annoying to 256extension. The background for this exytension is: It is very annoying to
227have 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
228codepath out of your transaction. While the BDB module still makes this 258codepath out of your transaction. While the BDB module still makes this
… …
254 284
255You can use the C<< $txn->failed >> method to check wether a transaction 285You can use the C<< $txn->failed >> method to check wether a transaction
256has failed in this way and abort further processing (excluding 286has failed in this way and abort further processing (excluding
257C<db_txn_finish>). 287C<db_txn_finish>).
258 288
289
259=head3 DB_ENV/database environment methods 290=head2 DB_ENV/database environment methods
260 291
261Methods available on DB_ENV/$env handles: 292Methods available on DB_ENV/$env handles:
262 293
263 DESTROY (DB_ENV_ornull *env) 294 DESTROY (DB_ENV_ornull *env)
264 CODE: 295 CODE:
… …
268 $int = $env->set_data_dir (const char *dir) 299 $int = $env->set_data_dir (const char *dir)
269 $int = $env->set_tmp_dir (const char *dir) 300 $int = $env->set_tmp_dir (const char *dir)
270 $int = $env->set_lg_dir (const char *dir) 301 $int = $env->set_lg_dir (const char *dir)
271 $int = $env->set_shm_key (long shm_key) 302 $int = $env->set_shm_key (long shm_key)
272 $int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0) 303 $int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0)
273 $int = $env->set_flags (U32 flags, int onoff) 304 $int = $env->set_flags (U32 flags, int onoff = 1)
305 $int = $env->log_set_config (U32 flags, int onoff = 1) (v4.7)
306 $int = $env->set_intermediate_dir_mode (const char *modestring) (v4.7)
274 $env->set_errfile (FILE *errfile = 0) 307 $env->set_errfile (FILE *errfile = 0)
275 $env->set_msgfile (FILE *msgfile = 0) 308 $env->set_msgfile (FILE *msgfile = 0)
276 $int = $env->set_verbose (U32 which, int onoff = 1) 309 $int = $env->set_verbose (U32 which, int onoff = 1)
277 $int = $env->set_encrypt (const char *password, U32 flags = 0) 310 $int = $env->set_encrypt (const char *password, U32 flags = 0)
278 $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)
… …
290 $int = $env->mutex_set_max (U32 max) 323 $int = $env->mutex_set_max (U32 max)
291 $int = $env->mutex_set_align (U32 align) 324 $int = $env->mutex_set_align (U32 align)
292 325
293 $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)
294 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
328 $txn = $env->cdsgroup_begin; (v4.5)
295 329
296=head4 Example: 330=head3 Example:
297 331
298 use AnyEvent; 332 use AnyEvent;
299 use BDB; 333 use BDB;
300 334
301 our $FH; open $FH, "<&=" . BDB::poll_fileno; 335 our $FH; open $FH, "<&=" . BDB::poll_fileno;
… …
313 0600; 347 0600;
314 348
315 $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1); 349 $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1);
316 350
317 351
318=head3 DB/database methods 352=head2 DB/database methods
319 353
320Methods available on DB/$db handles: 354Methods available on DB/$db handles:
321 355
322 DESTROY (DB_ornull *db) 356 DESTROY (DB_ornull *db)
323 CODE: 357 CODE:
… …
349 383
350 $dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0) 384 $dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0)
351 flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT 385 flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT
352 $seq = $db->sequence (U32 flags = 0) 386 $seq = $db->sequence (U32 flags = 0)
353 387
354=head4 Example: 388=head3 Example:
355 389
356 my $db = db_create $env; 390 my $db = db_create $env;
357 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;
358 392
359 for (1..1000) { 393 for (1..1000) {
… …
366 db_del $db, undef, "key $_" for 1..1000; 400 db_del $db, undef, "key $_" for 1..1000;
367 401
368 db_sync $db; 402 db_sync $db;
369 403
370 404
371=head3 DB_TXN/transaction methods 405=head2 DB_TXN/transaction methods
372 406
373Methods available on DB_TXN/$txn handles: 407Methods available on DB_TXN/$txn handles:
374 408
375 DESTROY (DB_TXN_ornull *txn) 409 DESTROY (DB_TXN_ornull *txn)
376 CODE: 410 CODE:
… …
382 416
383 $bool = $txn->failed 417 $bool = $txn->failed
384 # see db_txn_finish documentation, above 418 # see db_txn_finish documentation, above
385 419
386 420
387=head3 DBC/cursor methods 421=head2 DBC/cursor methods
388 422
389Methods available on DBC/$dbc handles: 423Methods available on DBC/$dbc handles:
390 424
391 DESTROY (DBC_ornull *dbc) 425 DESTROY (DBC_ornull *dbc)
392 CODE: 426 CODE:
393 if (dbc) 427 if (dbc)
394 dbc->c_close (dbc); 428 dbc->c_close (dbc);
395 429
396 $int = $cursor->set_priority ($priority = PRIORITY_*) 430 $int = $cursor->set_priority ($priority = PRIORITY_*) (v4.6)
397 431
398=head4 Example: 432=head3 Example:
399 433
400 my $c = $db->cursor; 434 my $c = $db->cursor;
401 435
402 for (;;) { 436 for (;;) {
403 db_c_get $c, my $key, my $data, BDB::NEXT; 437 db_c_get $c, my $key, my $data, BDB::NEXT;
… …
406 } 440 }
407 441
408 db_c_close $c; 442 db_c_close $c;
409 443
410 444
411=head3 DB_SEQUENCE/sequence methods 445=head2 DB_SEQUENCE/sequence methods
412 446
413Methods available on DB_SEQUENCE/$seq handles: 447Methods available on DB_SEQUENCE/$seq handles:
414 448
415 DESTROY (DB_SEQUENCE_ornull *seq) 449 DESTROY (DB_SEQUENCE_ornull *seq)
416 CODE: 450 CODE:
… …
421 $int = $seq->set_cachesize (U32 size) 455 $int = $seq->set_cachesize (U32 size)
422 $int = $seq->set_flags (U32 flags) 456 $int = $seq->set_flags (U32 flags)
423 flags: SEQ_DEC SEQ_INC SEQ_WRAP 457 flags: SEQ_DEC SEQ_INC SEQ_WRAP
424 $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)
425 459
426=head4 Example: 460=head3 Example:
427 461
428 my $seq = $db->sequence; 462 my $seq = $db->sequence;
429 463
430 db_sequence_open $seq, undef, "seq", BDB::CREATE; 464 db_sequence_open $seq, undef, "seq", BDB::CREATE;
431 db_sequence_get $seq, undef, 1, my $value; 465 db_sequence_get $seq, undef, 1, my $value;
432 466
433 467
434=head2 SUPPORT FUNCTIONS 468=head1 SUPPORT FUNCTIONS
435 469
436=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 470=head2 EVENT PROCESSING AND EVENT LOOP INTEGRATION
437 471
438=over 4 472=over 4
439 473
440=item $msg = BDB::strerror [$errno] 474=item $msg = BDB::strerror [$errno]
441 475
442Returns the string corresponding to the given errno value. If no argument 476Returns the string corresponding to the given errno value. If no argument
443is given, use C<$!>. 477is given, use C<$!>.
478
479Note that the BDB module also patches the C<$!> variable directly, so you
480should be able to get a bdb error string by simply stringifying C<$!>.
444 481
445=item $fileno = BDB::poll_fileno 482=item $fileno = BDB::poll_fileno
446 483
447Return the I<request result pipe file descriptor>. This filehandle must be 484Return the I<request result pipe file descriptor>. This filehandle must be
448polled for reading by some mechanism outside this module (e.g. Event or 485polled for reading by some mechanism outside this module (e.g. Event or
… …
525 BDB::poll_wait, BDB::poll_cb 562 BDB::poll_wait, BDB::poll_cb
526 while BDB::nreqs; 563 while BDB::nreqs;
527 564
528=back 565=back
529 566
567=head2 VERSION CHECKING
568
569BerkeleyDB comes in various versions, many of them have minor
570incompatibilities. This means that traditional "at least version x.x"
571checks are often not sufficient.
572
573Example: set the log_autoremove option in a way compatible with <v4.7 and
574v4.7. Note the use of & on the constants to avoid triggering a compiletime
575bug when the symbol isn't available.
576
577 $DB_ENV->set_flags (&BDB::LOG_AUTOREMOVE ) if BDB::VERSION v0, v4.7;
578 $DB_ENV->log_set_config (&BDB::LOG_AUTO_REMOVE) if BDB::VERSION v4.7;
579
580=over 4
581
582=item BDB::VERSION
583
584The C<BDB::VERSION> function, when called without arguments, returns the
585Berkeley DB version as a v-string (usually with 3 components). You should
586use C<lt> and C<ge> operators exclusively to make comparisons.
587
588Example: check for at least version 4.7.
589
590 BDB::VERSION ge v4.7 or die;
591
592=item BDB::VERSION min-version
593
594Returns true if the BDB version is at least the given version (specified
595as a v-string), false otherwise.
596
597Example: check for at least version 4.5.
598
599 BDB::VERSION v4.7 or die;
600
601=item BDB::VERSION min-version, max-version
602
603Returns true of the BDB version is at least version C<min-version> (specify C<undef> or C<v0> for any minimum version)
604and less then C<max-version>.
605
606Example: check wether version is strictly less then v4.7.
607
608 BDB::VERSION v0, v4.7
609 or die "version 4.7 is not yet supported";
610
611=back
612
613=cut
614
615sub VERSION {
616 # I was dumb enough to override the VERSION method here, so let's try
617 # to fix it up.
618
619 if ($_[0] eq __PACKAGE__) {
620 $VERSION
621 } else {
622 if (@_ > 0) {
623 return undef if VERSION_v lt $_[0];
624 if (@_ > 1) {
625 return undef if VERSION_v ge $_[1];
626 }
627 }
628
629 VERSION_v
630 }
631}
632
530=head3 CONTROLLING THE NUMBER OF THREADS 633=head2 CONTROLLING THE NUMBER OF THREADS
531 634
532=over 4 635=over 4
533 636
534=item BDB::min_parallel $nthreads 637=item BDB::min_parallel $nthreads
535 638
… …
596 699
597You can still queue as many requests as you want. Therefore, 700You can still queue as many requests as you want. Therefore,
598C<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
599as 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).
600 703
601=item BDB::set_sync_prepare $cb 704=item $old_cb = BDB::set_sync_prepare $cb
602 705
603Sets a callback that is called whenever a request is created without an 706Sets a callback that is called whenever a request is created without an
604explicit callback. It has to return two code references. The first is used 707explicit callback. It has to return two code references. The first is used
605as the request callback, and the second is called to wait until the first 708as the request callback (it should save the return status), and the second
606callback has been called. The default implementation works like this: 709is called to wait until the first callback has been called (it must set
710C<$!> to the return status).
711
712This mechanism can be used to include BDB into other event mechanisms,
713such as L<Coro::BDB>.
714
715To allow other, callback-based, events to be executed while callback-less
716ones are run, you could use this sync prepare function:
607 717
608 sub { 718 sub {
609 my $status; 719 my $status;
610 ( 720 (
611 sub { $status = $! }, 721 sub { $status = $! },
612 sub { BDB::poll while !defined $status; $! = $status }, 722 sub { BDB::poll while !defined $status; $! = $status },
613 ) 723 )
614 } 724 }
615 725
726It works by polling for results till the request has finished and then
727sets C<$!> to the return value. This means that if you don't use a
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.
733
616=back 734=back
617 735
618=head3 STATISTICAL INFORMATION 736=head2 STATISTICAL INFORMATION
619 737
620=over 4 738=over 4
621 739
622=item BDB::nreqs 740=item BDB::nreqs
623 741
… …
641 759
642=back 760=back
643 761
644=cut 762=cut
645 763
646set_sync_prepare { 764set_sync_prepare (undef);
647 my $status;
648 (
649 sub {
650 $status = $!;
651 },
652 sub {
653 BDB::poll while !defined $status;
654 $! = $status;
655 },
656 )
657};
658 765
659min_parallel 8; 766min_parallel 8;
660 767
661END { flush } 768END { flush }
662 769
6631; 7701;
664 771
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
665=head2 FORK BEHAVIOUR 795=head1 FORK BEHAVIOUR
666 796
667This 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:
668 798
669Before the fork, BDB enters a quiescent state where no requests 799Before the fork, BDB enters a quiescent state where no requests
670can 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
… …
680 810
681Win32 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
682broken 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
683yet, switch to a more capable platform. 813yet, switch to a more capable platform.
684 814
685=head2 MEMORY USAGE 815=head1 MEMORY USAGE
686 816
687Per-request usage: 817Per-request usage:
688 818
689Each aio request uses - depending on your architecture - around 100-200 819Each aio request uses - depending on your architecture - around 100-200
690bytes of memory. In addition, stat requests need a stat buffer (possibly 820bytes of memory. In addition, stat requests need a stat buffer (possibly
… …
699 829
700In the execution phase, some aio requests require more memory for 830In the execution phase, some aio requests require more memory for
701temporary buffers, and each thread requires a stack and other data 831temporary buffers, and each thread requires a stack and other data
702structures (usually around 16k-128k, depending on the OS). 832structures (usually around 16k-128k, depending on the OS).
703 833
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
704=head1 KNOWN BUGS 843=head1 KNOWN BUGS
705 844
706Known bugs will be fixed in the next release, except: 845Known bugs will be fixed in the next release, except:
707 846
708 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
… …
710 TXN_DEADLOCK flag will be set on the transaction. See C<db_txn_finish>, 849 TXN_DEADLOCK flag will be set on the transaction. See C<db_txn_finish>,
711 above. 850 above.
712 851
713=head1 SEE ALSO 852=head1 SEE ALSO
714 853
715L<Coro::BDB>, L<IO::AIO>. 854L<AnyEvent::BDB> (event loop integration), L<Coro::BDB> (more natural
855syntax), L<IO::AIO> (nice to have).
716 856
717=head1 AUTHOR 857=head1 AUTHOR
718 858
719 Marc Lehmann <schmorp@schmorp.de> 859 Marc Lehmann <schmorp@schmorp.de>
720 http://home.schmorp.de/ 860 http://home.schmorp.de/

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