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Comparing BDB/BDB.pm (file contents):
Revision 1.34 by root, Sun Mar 30 06:17:31 2008 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:
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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 = '1.44'; 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 );
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134 135
135 require XSLoader; 136 require XSLoader;
136 XSLoader::load ("BDB", $VERSION); 137 XSLoader::load ("BDB", $VERSION);
137} 138}
138 139
139=head2 FILENAMES/DATABASE NAMES
140
141The BDB expects "binary" filenames (octet strings) for pathnames on POSIX
142systems, and "unicode" filenames (strings with characters potentially
143>255) on Win32 (expecting a Unicode win32 build - win32 is a total mess).
144
145=head2 BERKELEYDB FUNCTIONS 140=head1 BERKELEYDB FUNCTIONS
146 141
147All of these are functions. The create functions simply return a new 142All of these are functions. The create functions simply return a new
148object and never block. All the remaining functions take an optional 143object and never block. All the remaining functions take an optional
149callback as last argument. If it is missing, then the function will be 144callback as last argument. If it is missing, then the function will be
150executed synchronously. In both cases, C<$!> will reflect the return value 145executed synchronously. In both cases, C<$!> will reflect the return value
… …
154settings) are method calls on the relevant objects, so the rule of thumb 149settings) are method calls on the relevant objects, so the rule of thumb
155is: if it's a method, it's not blocking, if it's a function, it takes a 150is: if it's a method, it's not blocking, if it's a function, it takes a
156callback as last argument. 151callback as last argument.
157 152
158In the following, C<$int> signifies an integer return value, 153In the following, C<$int> signifies an integer return value,
159C<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),
160indices >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
161integer, C<NV> is a floating point value. 156floating point value.
162 157
163The 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
164values), and the C<SV *callback> is the optional callback function to call 159values).
165when the request is completed.
166 160
167The various C<DB_ENV> etc. arguments are handles return by 161The various C<DB_ENV> etc. arguments are handles return by
168C<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
169appended 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>
170for them, resulting a NULL pointer on the C level. 164for them, resulting a NULL pointer on the C level.
171 165
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
172=head3 BDB functions 189=head2 BDB functions
173 190
174Functions in the BDB namespace, exported by default: 191Functions in the BDB namespace, exported by default:
175 192
176 $env = db_env_create (U32 env_flags = 0) 193 $env = db_env_create (U32 env_flags = 0)
177 flags: RPCCLIENT 194 flags: RPCCLIENT
178 195
179 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)
180 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
181 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)
182 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)
183 flags: FORCE 200 flags: FORCE
184 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)
185 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
186 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)
187 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)
188 210
189 $db = db_create (DB_ENV *env = 0, U32 flags = 0) 211 $db = db_create (DB_ENV *env = 0, U32 flags = 0)
190 flags: XA_CREATE 212 flags: XA_CREATE
191 213
192 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)
193 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
194 db_close (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) 216 db_close (DB *db, U32 flags = 0, SV *callback = 0)
195 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)
196 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)
197 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)
198 flags: FREELIST_ONLY FREE_SPACE 221 flags: FREELIST_ONLY FREE_SPACE
199 db_sync (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) 222 db_sync (DB *db, U32 flags = 0, SV *callback = 0)
200 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)
201 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)
202 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)
203 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)
204 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
205 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)
206 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
207 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)
208 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)
209 flags: TXN_NOSYNC TXN_SYNC 233 flags: TXN_NOSYNC TXN_SYNC
210 db_txn_abort (DB_TXN *txn, SV *callback = &PL_sv_undef) 234 db_txn_abort (DB_TXN *txn, SV *callback = 0)
211 235
212 db_c_close (DBC *dbc, SV *callback = &PL_sv_undef) 236 db_c_close (DBC *dbc, SV *callback = 0)
213 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)
214 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)
215 flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA 239 flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA
216 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)
217 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
218 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)
219 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)
220 244
221 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)
222 flags: CREATE EXCL 246 flags: CREATE EXCL
223 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)
224 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)
225 flags: TXN_NOSYNC 249 flags: TXN_NOSYNC
226 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)
227 flags: TXN_NOSYNC 251 flags: TXN_NOSYNC
228 252
229=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)
230 254
231This is not actually a Berkeley DB function but a BDB module 255This is not actually a Berkeley DB function but a BDB module
232extension. The background for this exytension is: It is very annoying to 256extension. The background for this exytension is: It is very annoying to
233have 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
234codepath out of your transaction. While the BDB module still makes this 258codepath out of your transaction. While the BDB module still makes this
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260 284
261You can use the C<< $txn->failed >> method to check wether a transaction 285You can use the C<< $txn->failed >> method to check wether a transaction
262has failed in this way and abort further processing (excluding 286has failed in this way and abort further processing (excluding
263C<db_txn_finish>). 287C<db_txn_finish>).
264 288
289
265=head3 DB_ENV/database environment methods 290=head2 DB_ENV/database environment methods
266 291
267Methods available on DB_ENV/$env handles: 292Methods available on DB_ENV/$env handles:
268 293
269 DESTROY (DB_ENV_ornull *env) 294 DESTROY (DB_ENV_ornull *env)
270 CODE: 295 CODE:
… …
274 $int = $env->set_data_dir (const char *dir) 299 $int = $env->set_data_dir (const char *dir)
275 $int = $env->set_tmp_dir (const char *dir) 300 $int = $env->set_tmp_dir (const char *dir)
276 $int = $env->set_lg_dir (const char *dir) 301 $int = $env->set_lg_dir (const char *dir)
277 $int = $env->set_shm_key (long shm_key) 302 $int = $env->set_shm_key (long shm_key)
278 $int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0) 303 $int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0)
279 $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)
280 $env->set_errfile (FILE *errfile = 0) 307 $env->set_errfile (FILE *errfile = 0)
281 $env->set_msgfile (FILE *msgfile = 0) 308 $env->set_msgfile (FILE *msgfile = 0)
282 $int = $env->set_verbose (U32 which, int onoff = 1) 309 $int = $env->set_verbose (U32 which, int onoff = 1)
283 $int = $env->set_encrypt (const char *password, U32 flags = 0) 310 $int = $env->set_encrypt (const char *password, U32 flags = 0)
284 $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)
… …
296 $int = $env->mutex_set_max (U32 max) 323 $int = $env->mutex_set_max (U32 max)
297 $int = $env->mutex_set_align (U32 align) 324 $int = $env->mutex_set_align (U32 align)
298 325
299 $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)
300 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)
301 329
302=head4 Example: 330=head3 Example:
303 331
304 use AnyEvent; 332 use AnyEvent;
305 use BDB; 333 use BDB;
306 334
307 our $FH; open $FH, "<&=" . BDB::poll_fileno; 335 our $FH; open $FH, "<&=" . BDB::poll_fileno;
… …
319 0600; 347 0600;
320 348
321 $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1); 349 $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1);
322 350
323 351
324=head3 DB/database methods 352=head2 DB/database methods
325 353
326Methods available on DB/$db handles: 354Methods available on DB/$db handles:
327 355
328 DESTROY (DB_ornull *db) 356 DESTROY (DB_ornull *db)
329 CODE: 357 CODE:
… …
355 383
356 $dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0) 384 $dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0)
357 flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT 385 flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT
358 $seq = $db->sequence (U32 flags = 0) 386 $seq = $db->sequence (U32 flags = 0)
359 387
360=head4 Example: 388=head3 Example:
361 389
362 my $db = db_create $env; 390 my $db = db_create $env;
363 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;
364 392
365 for (1..1000) { 393 for (1..1000) {
… …
372 db_del $db, undef, "key $_" for 1..1000; 400 db_del $db, undef, "key $_" for 1..1000;
373 401
374 db_sync $db; 402 db_sync $db;
375 403
376 404
377=head3 DB_TXN/transaction methods 405=head2 DB_TXN/transaction methods
378 406
379Methods available on DB_TXN/$txn handles: 407Methods available on DB_TXN/$txn handles:
380 408
381 DESTROY (DB_TXN_ornull *txn) 409 DESTROY (DB_TXN_ornull *txn)
382 CODE: 410 CODE:
… …
388 416
389 $bool = $txn->failed 417 $bool = $txn->failed
390 # see db_txn_finish documentation, above 418 # see db_txn_finish documentation, above
391 419
392 420
393=head3 DBC/cursor methods 421=head2 DBC/cursor methods
394 422
395Methods available on DBC/$dbc handles: 423Methods available on DBC/$dbc handles:
396 424
397 DESTROY (DBC_ornull *dbc) 425 DESTROY (DBC_ornull *dbc)
398 CODE: 426 CODE:
399 if (dbc) 427 if (dbc)
400 dbc->c_close (dbc); 428 dbc->c_close (dbc);
401 429
402 $int = $cursor->set_priority ($priority = PRIORITY_*) 430 $int = $cursor->set_priority ($priority = PRIORITY_*) (v4.6)
403 431
404=head4 Example: 432=head3 Example:
405 433
406 my $c = $db->cursor; 434 my $c = $db->cursor;
407 435
408 for (;;) { 436 for (;;) {
409 db_c_get $c, my $key, my $data, BDB::NEXT; 437 db_c_get $c, my $key, my $data, BDB::NEXT;
… …
412 } 440 }
413 441
414 db_c_close $c; 442 db_c_close $c;
415 443
416 444
417=head3 DB_SEQUENCE/sequence methods 445=head2 DB_SEQUENCE/sequence methods
418 446
419Methods available on DB_SEQUENCE/$seq handles: 447Methods available on DB_SEQUENCE/$seq handles:
420 448
421 DESTROY (DB_SEQUENCE_ornull *seq) 449 DESTROY (DB_SEQUENCE_ornull *seq)
422 CODE: 450 CODE:
… …
427 $int = $seq->set_cachesize (U32 size) 455 $int = $seq->set_cachesize (U32 size)
428 $int = $seq->set_flags (U32 flags) 456 $int = $seq->set_flags (U32 flags)
429 flags: SEQ_DEC SEQ_INC SEQ_WRAP 457 flags: SEQ_DEC SEQ_INC SEQ_WRAP
430 $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)
431 459
432=head4 Example: 460=head3 Example:
433 461
434 my $seq = $db->sequence; 462 my $seq = $db->sequence;
435 463
436 db_sequence_open $seq, undef, "seq", BDB::CREATE; 464 db_sequence_open $seq, undef, "seq", BDB::CREATE;
437 db_sequence_get $seq, undef, 1, my $value; 465 db_sequence_get $seq, undef, 1, my $value;
438 466
439 467
440=head2 SUPPORT FUNCTIONS 468=head1 SUPPORT FUNCTIONS
441 469
442=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 470=head2 EVENT PROCESSING AND EVENT LOOP INTEGRATION
443 471
444=over 4 472=over 4
445 473
446=item $msg = BDB::strerror [$errno] 474=item $msg = BDB::strerror [$errno]
447 475
… …
534 BDB::poll_wait, BDB::poll_cb 562 BDB::poll_wait, BDB::poll_cb
535 while BDB::nreqs; 563 while BDB::nreqs;
536 564
537=back 565=back
538 566
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
539=head3 CONTROLLING THE NUMBER OF THREADS 633=head2 CONTROLLING THE NUMBER OF THREADS
540 634
541=over 4 635=over 4
542 636
543=item BDB::min_parallel $nthreads 637=item BDB::min_parallel $nthreads
544 638
… …
605 699
606You can still queue as many requests as you want. Therefore, 700You can still queue as many requests as you want. Therefore,
607C<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
608as 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).
609 703
610=item BDB::set_sync_prepare $cb 704=item $old_cb = BDB::set_sync_prepare $cb
611 705
612Sets a callback that is called whenever a request is created without an 706Sets a callback that is called whenever a request is created without an
613explicit callback. It has to return two code references. The first is used 707explicit callback. It has to return two code references. The first is used
614as the request callback, and the second is called to wait until the first 708as the request callback (it should save the return status), and the second
615callback has been called. The default implementation works like this: 709is called to wait until the first callback has been called (it must set
710C<$!> 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:
616 717
617 sub { 718 sub {
618 my $status; 719 my $status;
619 ( 720 (
620 sub { $status = $! }, 721 sub { $status = $! },
621 sub { BDB::poll while !defined $status; $! = $status }, 722 sub { BDB::poll while !defined $status; $! = $status },
622 ) 723 )
623 } 724 }
624 725
726It works by polling for results till the request has finished and then
727sets C<$!> 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
625=back 734=back
626 735
627=head3 STATISTICAL INFORMATION 736=head2 STATISTICAL INFORMATION
628 737
629=over 4 738=over 4
630 739
631=item BDB::nreqs 740=item BDB::nreqs
632 741
… …
650 759
651=back 760=back
652 761
653=cut 762=cut
654 763
655set_sync_prepare { 764set_sync_prepare (undef);
656 my $status;
657 (
658 sub {
659 $status = $!;
660 },
661 sub {
662 BDB::poll while !defined $status;
663 $! = $status;
664 },
665 )
666};
667 765
668min_parallel 8; 766min_parallel 8;
669 767
670END { flush } 768END { flush }
671 769
6721; 7701;
673 771
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
674=head2 FORK BEHAVIOUR 795=head1 FORK BEHAVIOUR
675 796
676This 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:
677 798
678Before the fork, BDB enters a quiescent state where no requests 799Before the fork, BDB enters a quiescent state where no requests
679can 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
… …
689 810
690Win32 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
691broken 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
692yet, switch to a more capable platform. 813yet, switch to a more capable platform.
693 814
694=head2 MEMORY USAGE 815=head1 MEMORY USAGE
695 816
696Per-request usage: 817Per-request usage:
697 818
698Each aio request uses - depending on your architecture - around 100-200 819Each aio request uses - depending on your architecture - around 100-200
699bytes of memory. In addition, stat requests need a stat buffer (possibly 820bytes of memory. In addition, stat requests need a stat buffer (possibly
… …
708 829
709In the execution phase, some aio requests require more memory for 830In the execution phase, some aio requests require more memory for
710temporary buffers, and each thread requires a stack and other data 831temporary buffers, and each thread requires a stack and other data
711structures (usually around 16k-128k, depending on the OS). 832structures (usually around 16k-128k, depending on the OS).
712 833
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
713=head1 KNOWN BUGS 843=head1 KNOWN BUGS
714 844
715Known bugs will be fixed in the next release, except: 845Known bugs will be fixed in the next release, except:
716 846
717 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
… …
719 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>,
720 above. 850 above.
721 851
722=head1 SEE ALSO 852=head1 SEE ALSO
723 853
724L<Coro::BDB>, L<IO::AIO>. 854L<AnyEvent::BDB> (event loop integration), L<Coro::BDB> (more natural
855syntax), L<IO::AIO> (nice to have).
725 856
726=head1 AUTHOR 857=head1 AUTHOR
727 858
728 Marc Lehmann <schmorp@schmorp.de> 859 Marc Lehmann <schmorp@schmorp.de>
729 http://home.schmorp.de/ 860 http://home.schmorp.de/

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