ViewVC Help
View File | Revision Log | Show Annotations | Download File
/cvs/BDB/BDB.pm
(Generate patch)

Comparing BDB/BDB.pm (file contents):
Revision 1.37 by root, Mon Jul 7 14:28:53 2008 UTC vs.
Revision 1.69 by root, Tue Feb 2 04:28:06 2016 UTC

… …
27 db_sync $db; 27 db_sync $db;
28 28
29 # when you also use Coro, management is easy: 29 # when you also use Coro, management is easy:
30 use Coro::BDB; 30 use Coro::BDB;
31 31
32 # automatic event loop intergration with AnyEvent: 32 # automatic event loop integration with AnyEvent:
33 use AnyEvent::BDB; 33 use AnyEvent::BDB;
34 34
35 # automatic result processing with EV: 35 # automatic result processing with EV:
36 my $WATCHER = EV::io BDB::poll_fileno, EV::READ, \&BDB::poll_cb; 36 my $WATCHER = EV::io BDB::poll_fileno, EV::READ, \&BDB::poll_cb;
37 37
… …
103 103
104=cut 104=cut
105 105
106package BDB; 106package BDB;
107 107
108no warnings; 108use common::sense;
109use strict 'vars';
110 109
111use base 'Exporter'; 110use base 'Exporter';
112 111
112our $VERSION;
113
113BEGIN { 114BEGIN {
114 our $VERSION = '1.5'; 115 $VERSION = '1.91';
115 116
116 our @BDB_REQ = qw( 117 our @BDB_REQ = qw(
117 db_env_open db_env_close db_env_txn_checkpoint db_env_lock_detect 118 db_env_open db_env_close db_env_txn_checkpoint db_env_lock_detect
118 db_env_memp_sync db_env_memp_trickle 119 db_env_memp_sync db_env_memp_trickle db_env_dbrename db_env_dbremove
120 db_env_log_archive db_env_lsn_reset db_env_fileid_reset
119 db_open db_close db_compact db_sync db_upgrade 121 db_open db_close db_compact db_sync db_verify db_upgrade
120 db_put db_get db_pget db_del db_key_range 122 db_put db_exists db_get db_pget db_del db_key_range
121 db_txn_commit db_txn_abort db_txn_finish 123 db_txn_commit db_txn_abort db_txn_finish
122 db_c_close db_c_count db_c_put db_c_get db_c_pget db_c_del 124 db_c_close db_c_count db_c_put db_c_get db_c_pget db_c_del
123 db_sequence_open db_sequence_close 125 db_sequence_open db_sequence_close
124 db_sequence_get db_sequence_remove 126 db_sequence_get db_sequence_remove
125 ); 127 );
… …
133 135
134 require XSLoader; 136 require XSLoader;
135 XSLoader::load ("BDB", $VERSION); 137 XSLoader::load ("BDB", $VERSION);
136} 138}
137 139
138=head2 WIN32 FILENAMES/DATABASE NAME MESS
139
140Perl on Win32 supports only ASCII filenames (the reason is that it abuses
141an internal flag to store wether a filename is Unicode or ANSI, but that
142flag is used for somethign else in the perl core, so there is no way to
143detect wether a filename is ANSI or Unicode-encoded). The BDB module
144tries to work around this issue by assuming that the filename is an ANSI
145filename and BDB was built for unicode support.
146
147=head2 BERKELEYDB FUNCTIONS 140=head1 BERKELEYDB FUNCTIONS
148 141
149All of these are functions. The create functions simply return a new 142All of these are functions. The create functions simply return a new
150object and never block. All the remaining functions take an optional 143object and never block. All the remaining functions take an optional
151callback as last argument. If it is missing, then the function will be 144callback as last argument. If it is missing, then the function will be
152executed synchronously. In both cases, C<$!> will reflect the return value 145executed synchronously. In both cases, C<$!> will reflect the return value
… …
156settings) are method calls on the relevant objects, so the rule of thumb 149settings) are method calls on the relevant objects, so the rule of thumb
157is: if it's a method, it's not blocking, if it's a function, it takes a 150is: if it's a method, it's not blocking, if it's a function, it takes a
158callback as last argument. 151callback as last argument.
159 152
160In the following, C<$int> signifies an integer return value, 153In the following, C<$int> signifies an integer return value,
161C<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),
162indices >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
163integer, C<NV> is a floating point value. 156floating point value.
164 157
165The 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
166values), and the C<SV *callback> is the optional callback function to call 159values).
167when the request is completed.
168 160
169The various C<DB_ENV> etc. arguments are handles return by 161The various C<DB_ENV> etc. arguments are handles return by
170C<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
171appended 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>
172for them, resulting a NULL pointer on the C level. 164for them, resulting a NULL pointer on the C level.
173 165
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
174=head3 BDB functions 189=head2 BDB functions
175 190
176Functions in the BDB namespace, exported by default: 191Functions in the BDB namespace, exported by default:
177 192
178 $env = db_env_create (U32 env_flags = 0) 193 $env = db_env_create (U32 env_flags = 0)
179 flags: RPCCLIENT 194 flags: RPCCLIENT
180 195
181 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)
182 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
183 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)
184 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)
185 flags: FORCE 200 flags: FORCE
186 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)
187 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
188 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)
189 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)
190 210
191 $db = db_create (DB_ENV *env = 0, U32 flags = 0) 211 $db = db_create (DB_ENV *env = 0, U32 flags = 0)
192 flags: XA_CREATE 212 flags: XA_CREATE
193 213
194 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)
195 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
196 db_close (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) 216 db_close (DB *db, U32 flags = 0, SV *callback = 0)
197 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)
198 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)
199 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)
200 flags: FREELIST_ONLY FREE_SPACE 221 flags: FREELIST_ONLY FREE_SPACE
201 db_sync (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) 222 db_sync (DB *db, U32 flags = 0, SV *callback = 0)
202 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)
203 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)
204 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)
205 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)
206 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
207 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)
208 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
209 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)
210 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)
211 flags: TXN_NOSYNC TXN_SYNC 233 flags: TXN_NOSYNC TXN_SYNC
212 db_txn_abort (DB_TXN *txn, SV *callback = &PL_sv_undef) 234 db_txn_abort (DB_TXN *txn, SV *callback = 0)
213 235
214 db_c_close (DBC *dbc, SV *callback = &PL_sv_undef) 236 db_c_close (DBC *dbc, SV *callback = 0)
215 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)
216 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)
217 flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA 239 flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA
218 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)
219 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
220 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)
221 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)
222 244
223 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)
224 flags: CREATE EXCL 246 flags: CREATE EXCL
225 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)
226 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)
227 flags: TXN_NOSYNC 249 flags: TXN_NOSYNC
228 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)
229 flags: TXN_NOSYNC 251 flags: TXN_NOSYNC
230 252
231=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)
232 254
233This is not actually a Berkeley DB function but a BDB module 255This is not actually a Berkeley DB function but a BDB module
234extension. The background for this exytension is: It is very annoying to 256extension. The background for this exytension is: It is very annoying to
235have 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
236codepath out of your transaction. While the BDB module still makes this 258codepath out of your transaction. While the BDB module still makes this
… …
262 284
263You can use the C<< $txn->failed >> method to check wether a transaction 285You can use the C<< $txn->failed >> method to check wether a transaction
264has failed in this way and abort further processing (excluding 286has failed in this way and abort further processing (excluding
265C<db_txn_finish>). 287C<db_txn_finish>).
266 288
289
267=head3 DB_ENV/database environment methods 290=head2 DB_ENV/database environment methods
268 291
269Methods available on DB_ENV/$env handles: 292Methods available on DB_ENV/$env handles:
270 293
271 DESTROY (DB_ENV_ornull *env) 294 DESTROY (DB_ENV_ornull *env)
272 CODE: 295 CODE:
… …
276 $int = $env->set_data_dir (const char *dir) 299 $int = $env->set_data_dir (const char *dir)
277 $int = $env->set_tmp_dir (const char *dir) 300 $int = $env->set_tmp_dir (const char *dir)
278 $int = $env->set_lg_dir (const char *dir) 301 $int = $env->set_lg_dir (const char *dir)
279 $int = $env->set_shm_key (long shm_key) 302 $int = $env->set_shm_key (long shm_key)
280 $int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0) 303 $int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0)
281 $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)
282 $env->set_errfile (FILE *errfile = 0) 307 $env->set_errfile (FILE *errfile = 0)
283 $env->set_msgfile (FILE *msgfile = 0) 308 $env->set_msgfile (FILE *msgfile = 0)
284 $int = $env->set_verbose (U32 which, int onoff = 1) 309 $int = $env->set_verbose (U32 which, int onoff = 1)
285 $int = $env->set_encrypt (const char *password, U32 flags = 0) 310 $int = $env->set_encrypt (const char *password, U32 flags = 0)
286 $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)
… …
298 $int = $env->mutex_set_max (U32 max) 323 $int = $env->mutex_set_max (U32 max)
299 $int = $env->mutex_set_align (U32 align) 324 $int = $env->mutex_set_align (U32 align)
300 325
301 $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)
302 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)
303 329
304=head4 Example: 330=head3 Example:
305 331
306 use AnyEvent; 332 use AnyEvent;
307 use BDB; 333 use BDB;
308 334
309 our $FH; open $FH, "<&=" . BDB::poll_fileno; 335 our $FH; open $FH, "<&=" . BDB::poll_fileno;
… …
321 0600; 347 0600;
322 348
323 $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1); 349 $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1);
324 350
325 351
326=head3 DB/database methods 352=head2 DB/database methods
327 353
328Methods available on DB/$db handles: 354Methods available on DB/$db handles:
329 355
330 DESTROY (DB_ornull *db) 356 DESTROY (DB_ornull *db)
331 CODE: 357 CODE:
… …
357 383
358 $dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0) 384 $dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0)
359 flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT 385 flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT
360 $seq = $db->sequence (U32 flags = 0) 386 $seq = $db->sequence (U32 flags = 0)
361 387
362=head4 Example: 388=head3 Example:
363 389
364 my $db = db_create $env; 390 my $db = db_create $env;
365 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;
366 392
367 for (1..1000) { 393 for (1..1000) {
… …
374 db_del $db, undef, "key $_" for 1..1000; 400 db_del $db, undef, "key $_" for 1..1000;
375 401
376 db_sync $db; 402 db_sync $db;
377 403
378 404
379=head3 DB_TXN/transaction methods 405=head2 DB_TXN/transaction methods
380 406
381Methods available on DB_TXN/$txn handles: 407Methods available on DB_TXN/$txn handles:
382 408
383 DESTROY (DB_TXN_ornull *txn) 409 DESTROY (DB_TXN_ornull *txn)
384 CODE: 410 CODE:
… …
390 416
391 $bool = $txn->failed 417 $bool = $txn->failed
392 # see db_txn_finish documentation, above 418 # see db_txn_finish documentation, above
393 419
394 420
395=head3 DBC/cursor methods 421=head2 DBC/cursor methods
396 422
397Methods available on DBC/$dbc handles: 423Methods available on DBC/$dbc handles:
398 424
399 DESTROY (DBC_ornull *dbc) 425 DESTROY (DBC_ornull *dbc)
400 CODE: 426 CODE:
401 if (dbc) 427 if (dbc)
402 dbc->c_close (dbc); 428 dbc->c_close (dbc);
403 429
404 $int = $cursor->set_priority ($priority = PRIORITY_*) 430 $int = $cursor->set_priority ($priority = PRIORITY_*) (v4.6)
405 431
406=head4 Example: 432=head3 Example:
407 433
408 my $c = $db->cursor; 434 my $c = $db->cursor;
409 435
410 for (;;) { 436 for (;;) {
411 db_c_get $c, my $key, my $data, BDB::NEXT; 437 db_c_get $c, my $key, my $data, BDB::NEXT;
… …
414 } 440 }
415 441
416 db_c_close $c; 442 db_c_close $c;
417 443
418 444
419=head3 DB_SEQUENCE/sequence methods 445=head2 DB_SEQUENCE/sequence methods
420 446
421Methods available on DB_SEQUENCE/$seq handles: 447Methods available on DB_SEQUENCE/$seq handles:
422 448
423 DESTROY (DB_SEQUENCE_ornull *seq) 449 DESTROY (DB_SEQUENCE_ornull *seq)
424 CODE: 450 CODE:
… …
429 $int = $seq->set_cachesize (U32 size) 455 $int = $seq->set_cachesize (U32 size)
430 $int = $seq->set_flags (U32 flags) 456 $int = $seq->set_flags (U32 flags)
431 flags: SEQ_DEC SEQ_INC SEQ_WRAP 457 flags: SEQ_DEC SEQ_INC SEQ_WRAP
432 $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)
433 459
434=head4 Example: 460=head3 Example:
435 461
436 my $seq = $db->sequence; 462 my $seq = $db->sequence;
437 463
438 db_sequence_open $seq, undef, "seq", BDB::CREATE; 464 db_sequence_open $seq, undef, "seq", BDB::CREATE;
439 db_sequence_get $seq, undef, 1, my $value; 465 db_sequence_get $seq, undef, 1, my $value;
440 466
441 467
442=head2 SUPPORT FUNCTIONS 468=head1 SUPPORT FUNCTIONS
443 469
444=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 470=head2 EVENT PROCESSING AND EVENT LOOP INTEGRATION
445 471
446=over 4 472=over 4
447 473
448=item $msg = BDB::strerror [$errno] 474=item $msg = BDB::strerror [$errno]
449 475
… …
536 BDB::poll_wait, BDB::poll_cb 562 BDB::poll_wait, BDB::poll_cb
537 while BDB::nreqs; 563 while BDB::nreqs;
538 564
539=back 565=back
540 566
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
541=head3 CONTROLLING THE NUMBER OF THREADS 633=head2 CONTROLLING THE NUMBER OF THREADS
542 634
543=over 4 635=over 4
544 636
545=item BDB::min_parallel $nthreads 637=item BDB::min_parallel $nthreads
546 638
… …
607 699
608You can still queue as many requests as you want. Therefore, 700You can still queue as many requests as you want. Therefore,
609C<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
610as 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).
611 703
612=item BDB::set_sync_prepare $cb 704=item $old_cb = BDB::set_sync_prepare $cb
613 705
614Sets a callback that is called whenever a request is created without an 706Sets a callback that is called whenever a request is created without an
615explicit callback. It has to return two code references. The first is used 707explicit callback. It has to return two code references. The first is used
616as the request callback (it should save the return status), and the second 708as the request callback (it should save the return status), and the second
617is called to wait until the first callback has been called (it must set 709is called to wait until the first callback has been called (it must set
618C<$!> to the return status). 710C<$!> to the return status).
619 711
620This mechanism can be used to include BDB into other event mechanisms, 712This mechanism can be used to include BDB into other event mechanisms,
621such as L<AnyEvent::BDB> or L<Coro::BDB>. 713such as L<Coro::BDB>.
622 714
623The default implementation works like this: 715To allow other, callback-based, events to be executed while callback-less
716ones are run, you could use this sync prepare function:
624 717
625 sub { 718 sub {
626 my $status; 719 my $status;
627 ( 720 (
628 sub { $status = $! }, 721 sub { $status = $! },
629 sub { BDB::poll while !defined $status; $! = $status }, 722 sub { BDB::poll while !defined $status; $! = $status },
630 ) 723 )
631 } 724 }
632 725
633It simply blocks the process till the request has finished and then sets 726It works by polling for results till the request has finished and then
634C<$!> to the return value. This means that if you don't use a callback, 727sets C<$!> to the return value. This means that if you don't use a
635BDB will simply fall back to synchronous operations. 728callback, BDB would simply fall back to synchronous operations.
729
730By default, or if the sync prepare function is set to C<undef>, is to
731execute callback-less BDB requests in the foreground thread, setting C<$!>
732to the return value, without polling for other events.
636 733
637=back 734=back
638 735
639=head3 STATISTICAL INFORMATION 736=head2 STATISTICAL INFORMATION
640 737
641=over 4 738=over 4
642 739
643=item BDB::nreqs 740=item BDB::nreqs
644 741
… …
662 759
663=back 760=back
664 761
665=cut 762=cut
666 763
667set_sync_prepare { 764set_sync_prepare (undef);
668 my $status;
669 (
670 sub {
671 $status = $!;
672 },
673 sub {
674 BDB::poll while !defined $status;
675 $! = $status;
676 },
677 )
678};
679 765
680min_parallel 8; 766min_parallel 8;
681 767
682END { flush } 768END { flush }
683 769
6841; 7701;
685 771
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
686=head2 FORK BEHAVIOUR 795=head1 FORK BEHAVIOUR
687 796
688This 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:
689 798
690Before the fork, BDB enters a quiescent state where no requests 799Before the fork, BDB enters a quiescent state where no requests
691can 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
… …
701 810
702Win32 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
703broken 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
704yet, switch to a more capable platform. 813yet, switch to a more capable platform.
705 814
706=head2 MEMORY USAGE 815=head1 MEMORY USAGE
707 816
708Per-request usage: 817Per-request usage:
709 818
710Each aio request uses - depending on your architecture - around 100-200 819Each aio request uses - depending on your architecture - around 100-200
711bytes of memory. In addition, stat requests need a stat buffer (possibly 820bytes of memory. In addition, stat requests need a stat buffer (possibly
… …
720 829
721In the execution phase, some aio requests require more memory for 830In the execution phase, some aio requests require more memory for
722temporary buffers, and each thread requires a stack and other data 831temporary buffers, and each thread requires a stack and other data
723structures (usually around 16k-128k, depending on the OS). 832structures (usually around 16k-128k, depending on the OS).
724 833
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
725=head1 KNOWN BUGS 843=head1 KNOWN BUGS
726 844
727Known bugs will be fixed in the next release, except: 845Known bugs will be fixed in the next release, except:
728 846
729 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

Diff Legend

– Removed lines
+ Added lines
< Changed lines
> Changed lines