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Comparing BDB/BDB.pm (file contents):
Revision 1.35 by root, Sun Mar 30 08:01:58 2008 UTC vs.
Revision 1.69 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 result processing with AnyEvent: 32 # automatic event loop integration with AnyEvent:
33 our $FH; open $FH, "<&=" . BDB::poll_fileno; 33 use AnyEvent::BDB;
34 our $WATCHER = AnyEvent->io (fh => $FH, poll => 'r', cb => \&BDB::poll_cb);
35 34
36 # automatic result processing with EV: 35 # automatic result processing with EV:
37 my $WATCHER = EV::io BDB::poll_fileno, EV::READ, \&BDB::poll_cb; 36 my $WATCHER = EV::io BDB::poll_fileno, EV::READ, \&BDB::poll_cb;
38 37
39 # with Glib: 38 # with Glib:
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104 103
105=cut 104=cut
106 105
107package BDB; 106package BDB;
108 107
109no warnings; 108use common::sense;
110use strict 'vars';
111 109
112use base 'Exporter'; 110use base 'Exporter';
113 111
112our $VERSION;
113
114BEGIN { 114BEGIN {
115 our $VERSION = '1.45'; 115 $VERSION = '1.91';
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", $VERSION);
137} 138}
138 139
139=head2 WIN32 FILENAMES/DATABASE NAME MESS
140
141Perl on Win32 supports only ASCII filenames (the reason is that it abuses
142an internal flag to store wether a filename is Unicode or ANSI, but that
143flag is used for somethign else in the perl core, so there is no way to
144detect wether a filename is ANSI or Unicode-encoded). The BDB module
145tries to work around this issue by assuming that the filename is an ANSI
146filename and BDB was built for unicode support.
147
148=head2 BERKELEYDB FUNCTIONS 140=head1 BERKELEYDB FUNCTIONS
149 141
150All of these are functions. The create functions simply return a new 142All of these are functions. The create functions simply return a new
151object and never block. All the remaining functions take an optional 143object and never block. All the remaining functions take an optional
152callback as last argument. If it is missing, then the function will be 144callback as last argument. If it is missing, then the function will be
153executed synchronously. In both cases, C<$!> will reflect the return value 145executed synchronously. In both cases, C<$!> will reflect the return value
… …
157settings) are method calls on the relevant objects, so the rule of thumb 149settings) are method calls on the relevant objects, so the rule of thumb
158is: if it's a method, it's not blocking, if it's a function, it takes a 150is: if it's a method, it's not blocking, if it's a function, it takes a
159callback as last argument. 151callback as last argument.
160 152
161In the following, C<$int> signifies an integer return value, 153In the following, C<$int> signifies an integer return value,
162C<octetstring> is a "binary string" (i.e. a perl string with no character 154C<bdb_filename> is a "filename" (octets on unix, madness on windows),
163indices >255), C<U32> is an unsigned 32 bit integer, C<int> is some 155C<U32> is an unsigned 32 bit integer, C<int> is some integer, C<NV> is a
164integer, C<NV> is a floating point value. 156floating point value.
165 157
166The C<SV *> types are generic perl scalars (for input and output of data 158Most C<SV *> types are generic perl scalars (for input and output of data
167values), and the C<SV *callback> is the optional callback function to call 159values).
168when the request is completed.
169 160
170The various C<DB_ENV> etc. arguments are handles return by 161The various C<DB_ENV> etc. arguments are handles return by
171C<db_env_create>, C<db_create>, C<txn_begin> and so on. If they have an 162C<db_env_create>, C<db_create>, C<txn_begin> and so on. If they have an
172appended C<_ornull> this means they are optional and you can pass C<undef> 163appended C<_ornull> this means they are optional and you can pass C<undef>
173for them, resulting a NULL pointer on the C level. 164for them, resulting a NULL pointer on the C level.
174 165
166The C<SV *callback> is the optional callback function to call when the
167request is completed. This last callback argument is special: the callback
168is simply the last argument passed. If there are "optional" arguments
169before the callback they can be left out. The callback itself can be left
170out or specified as C<undef>, in which case the function will be executed
171synchronously.
172
173For example, C<db_env_txn_checkpoint> usually is called with all integer
174arguments zero. These can be left out, so all of these specify a call
175to C<< DB_ENV->txn_checkpoint >>, to be executed asynchronously with a
176callback to be called:
177
178 db_env_txn_checkpoint $db_env, 0, 0, 0, sub { };
179 db_env_txn_checkpoint $db_env, 0, 0, sub { };
180 db_env_txn_checkpoint $db_env, sub { };
181
182While these all specify a call to C<< DB_ENV->txn_checkpoint >> to be
183executed synchronously:
184
185 db_env_txn_checkpoint $db_env, 0, 0, 0, undef;
186 db_env_txn_checkpoint $db_env, 0, 0, 0;
187 db_env_txn_checkpoint $db_env, 0;
188
175=head3 BDB functions 189=head2 BDB functions
176 190
177Functions in the BDB namespace, exported by default: 191Functions in the BDB namespace, exported by default:
178 192
179 $env = db_env_create (U32 env_flags = 0) 193 $env = db_env_create (U32 env_flags = 0)
180 flags: RPCCLIENT 194 flags: RPCCLIENT
181 195
182 db_env_open (DB_ENV *env, octetstring db_home, U32 open_flags, int mode, SV *callback = &PL_sv_undef) 196 db_env_open (DB_ENV *env, bdb_filename db_home, U32 open_flags, int mode, SV *callback = 0)
183 open_flags: INIT_CDB INIT_LOCK INIT_LOG INIT_MPOOL INIT_REP INIT_TXN RECOVER RECOVER_FATAL USE_ENVIRON USE_ENVIRON_ROOT CREATE LOCKDOWN PRIVATE REGISTER SYSTEM_MEM 197 open_flags: INIT_CDB INIT_LOCK INIT_LOG INIT_MPOOL INIT_REP INIT_TXN RECOVER RECOVER_FATAL USE_ENVIRON USE_ENVIRON_ROOT CREATE LOCKDOWN PRIVATE REGISTER SYSTEM_MEM
184 db_env_close (DB_ENV *env, U32 flags = 0, SV *callback = &PL_sv_undef) 198 db_env_close (DB_ENV *env, U32 flags = 0, SV *callback = 0)
185 db_env_txn_checkpoint (DB_ENV *env, U32 kbyte = 0, U32 min = 0, U32 flags = 0, SV *callback = &PL_sv_undef) 199 db_env_txn_checkpoint (DB_ENV *env, U32 kbyte = 0, U32 min = 0, U32 flags = 0, SV *callback = 0)
186 flags: FORCE 200 flags: FORCE
187 db_env_lock_detect (DB_ENV *env, U32 flags = 0, U32 atype = DB_LOCK_DEFAULT, SV *dummy = 0, SV *callback = &PL_sv_undef) 201 db_env_lock_detect (DB_ENV *env, U32 flags = 0, U32 atype = DB_LOCK_DEFAULT, SV *dummy = 0, SV *callback = 0)
188 atype: LOCK_DEFAULT LOCK_EXPIRE LOCK_MAXLOCKS LOCK_MAXWRITE LOCK_MINLOCKS LOCK_MINWRITE LOCK_OLDEST LOCK_RANDOM LOCK_YOUNGEST 202 atype: LOCK_DEFAULT LOCK_EXPIRE LOCK_MAXLOCKS LOCK_MAXWRITE LOCK_MINLOCKS LOCK_MINWRITE LOCK_OLDEST LOCK_RANDOM LOCK_YOUNGEST
189 db_env_memp_sync (DB_ENV *env, SV *dummy = 0, SV *callback = &PL_sv_undef) 203 db_env_memp_sync (DB_ENV *env, SV *dummy = 0, SV *callback = 0)
190 db_env_memp_trickle (DB_ENV *env, int percent, SV *dummy = 0, SV *callback = &PL_sv_undef) 204 db_env_memp_trickle (DB_ENV *env, int percent, SV *dummy = 0, SV *callback = 0)
205 db_env_dbremove (DB_ENV *env, DB_TXN_ornull *txnid, bdb_filename file, bdb_filename database, U32 flags = 0, SV *callback = 0)
206 db_env_dbrename (DB_ENV *env, DB_TXN_ornull *txnid, bdb_filename file, bdb_filename database, bdb_filename newname, U32 flags = 0, SV *callback = 0)
207 db_env_log_archive (DB_ENV *env, SV *listp, U32 flags = 0, SV *callback = 0)
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)
191 210
192 $db = db_create (DB_ENV *env = 0, U32 flags = 0) 211 $db = db_create (DB_ENV *env = 0, U32 flags = 0)
193 flags: XA_CREATE 212 flags: XA_CREATE
194 213
195 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)
196 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
197 db_close (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) 216 db_close (DB *db, U32 flags = 0, SV *callback = 0)
198 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)
199 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)
200 db_compact (DB *db, DB_TXN_ornull *txn = 0, SV *start = 0, SV *stop = 0, SV *unused1 = 0, U32 flags = DB_FREE_SPACE, SV *unused2 = 0, SV *callback = &PL_sv_undef) 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)
201 flags: FREELIST_ONLY FREE_SPACE 221 flags: FREELIST_ONLY FREE_SPACE
202 db_sync (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) 222 db_sync (DB *db, U32 flags = 0, SV *callback = 0)
203 db_key_range (DB *db, DB_TXN_ornull *txn, SV *key, SV *key_range, U32 flags = 0, SV *callback = &PL_sv_undef) 223 db_key_range (DB *db, DB_TXN_ornull *txn, SV *key, SV *key_range, U32 flags = 0, SV *callback = 0)
204 db_put (DB *db, DB_TXN_ornull *txn, SV *key, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) 224 db_put (DB *db, DB_TXN_ornull *txn, SV *key, SV *data, U32 flags = 0, SV *callback = 0)
205 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)
206 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)
207 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
208 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)
209 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
210 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)
211 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)
212 flags: TXN_NOSYNC TXN_SYNC 233 flags: TXN_NOSYNC TXN_SYNC
213 db_txn_abort (DB_TXN *txn, SV *callback = &PL_sv_undef) 234 db_txn_abort (DB_TXN *txn, SV *callback = 0)
214 235
215 db_c_close (DBC *dbc, SV *callback = &PL_sv_undef) 236 db_c_close (DBC *dbc, SV *callback = 0)
216 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)
217 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)
218 flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA 239 flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA
219 db_c_get (DBC *dbc, SV *key, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) 240 db_c_get (DBC *dbc, SV *key, SV *data, U32 flags = 0, SV *callback = 0)
220 flags: CURRENT FIRST GET_BOTH GET_BOTH_RANGE GET_RECNO JOIN_ITEM LAST NEXT NEXT_DUP NEXT_NODUP PREV PREV_DUP PREV_NODUP SET SET_RANGE SET_RECNO READ_UNCOMMITTED MULTIPLE MULTIPLE_KEY RMW 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
221 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)
222 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)
223 244
224 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)
225 flags: CREATE EXCL 246 flags: CREATE EXCL
226 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)
227 db_sequence_get (DB_SEQUENCE *seq, DB_TXN_ornull *txnid, int delta, SV *seq_value, U32 flags = DB_TXN_NOSYNC, SV *callback = &PL_sv_undef) 248 db_sequence_get (DB_SEQUENCE *seq, DB_TXN_ornull *txnid, int delta, SV *seq_value, U32 flags = DB_TXN_NOSYNC, SV *callback = 0)
228 flags: TXN_NOSYNC 249 flags: TXN_NOSYNC
229 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)
230 flags: TXN_NOSYNC 251 flags: TXN_NOSYNC
231 252
232=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)
233 254
234This is not actually a Berkeley DB function but a BDB module 255This is not actually a Berkeley DB function but a BDB module
235extension. The background for this exytension is: It is very annoying to 256extension. The background for this exytension is: It is very annoying to
236have 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
237codepath 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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263 284
264You can use the C<< $txn->failed >> method to check wether a transaction 285You can use the C<< $txn->failed >> method to check wether a transaction
265has failed in this way and abort further processing (excluding 286has failed in this way and abort further processing (excluding
266C<db_txn_finish>). 287C<db_txn_finish>).
267 288
289
268=head3 DB_ENV/database environment methods 290=head2 DB_ENV/database environment methods
269 291
270Methods available on DB_ENV/$env handles: 292Methods available on DB_ENV/$env handles:
271 293
272 DESTROY (DB_ENV_ornull *env) 294 DESTROY (DB_ENV_ornull *env)
273 CODE: 295 CODE:
… …
277 $int = $env->set_data_dir (const char *dir) 299 $int = $env->set_data_dir (const char *dir)
278 $int = $env->set_tmp_dir (const char *dir) 300 $int = $env->set_tmp_dir (const char *dir)
279 $int = $env->set_lg_dir (const char *dir) 301 $int = $env->set_lg_dir (const char *dir)
280 $int = $env->set_shm_key (long shm_key) 302 $int = $env->set_shm_key (long shm_key)
281 $int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0) 303 $int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0)
282 $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)
283 $env->set_errfile (FILE *errfile = 0) 307 $env->set_errfile (FILE *errfile = 0)
284 $env->set_msgfile (FILE *msgfile = 0) 308 $env->set_msgfile (FILE *msgfile = 0)
285 $int = $env->set_verbose (U32 which, int onoff = 1) 309 $int = $env->set_verbose (U32 which, int onoff = 1)
286 $int = $env->set_encrypt (const char *password, U32 flags = 0) 310 $int = $env->set_encrypt (const char *password, U32 flags = 0)
287 $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)
… …
299 $int = $env->mutex_set_max (U32 max) 323 $int = $env->mutex_set_max (U32 max)
300 $int = $env->mutex_set_align (U32 align) 324 $int = $env->mutex_set_align (U32 align)
301 325
302 $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)
303 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)
304 329
305=head4 Example: 330=head3 Example:
306 331
307 use AnyEvent; 332 use AnyEvent;
308 use BDB; 333 use BDB;
309 334
310 our $FH; open $FH, "<&=" . BDB::poll_fileno; 335 our $FH; open $FH, "<&=" . BDB::poll_fileno;
… …
322 0600; 347 0600;
323 348
324 $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1); 349 $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1);
325 350
326 351
327=head3 DB/database methods 352=head2 DB/database methods
328 353
329Methods available on DB/$db handles: 354Methods available on DB/$db handles:
330 355
331 DESTROY (DB_ornull *db) 356 DESTROY (DB_ornull *db)
332 CODE: 357 CODE:
… …
358 383
359 $dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0) 384 $dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0)
360 flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT 385 flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT
361 $seq = $db->sequence (U32 flags = 0) 386 $seq = $db->sequence (U32 flags = 0)
362 387
363=head4 Example: 388=head3 Example:
364 389
365 my $db = db_create $env; 390 my $db = db_create $env;
366 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;
367 392
368 for (1..1000) { 393 for (1..1000) {
… …
375 db_del $db, undef, "key $_" for 1..1000; 400 db_del $db, undef, "key $_" for 1..1000;
376 401
377 db_sync $db; 402 db_sync $db;
378 403
379 404
380=head3 DB_TXN/transaction methods 405=head2 DB_TXN/transaction methods
381 406
382Methods available on DB_TXN/$txn handles: 407Methods available on DB_TXN/$txn handles:
383 408
384 DESTROY (DB_TXN_ornull *txn) 409 DESTROY (DB_TXN_ornull *txn)
385 CODE: 410 CODE:
… …
391 416
392 $bool = $txn->failed 417 $bool = $txn->failed
393 # see db_txn_finish documentation, above 418 # see db_txn_finish documentation, above
394 419
395 420
396=head3 DBC/cursor methods 421=head2 DBC/cursor methods
397 422
398Methods available on DBC/$dbc handles: 423Methods available on DBC/$dbc handles:
399 424
400 DESTROY (DBC_ornull *dbc) 425 DESTROY (DBC_ornull *dbc)
401 CODE: 426 CODE:
402 if (dbc) 427 if (dbc)
403 dbc->c_close (dbc); 428 dbc->c_close (dbc);
404 429
405 $int = $cursor->set_priority ($priority = PRIORITY_*) 430 $int = $cursor->set_priority ($priority = PRIORITY_*) (v4.6)
406 431
407=head4 Example: 432=head3 Example:
408 433
409 my $c = $db->cursor; 434 my $c = $db->cursor;
410 435
411 for (;;) { 436 for (;;) {
412 db_c_get $c, my $key, my $data, BDB::NEXT; 437 db_c_get $c, my $key, my $data, BDB::NEXT;
… …
415 } 440 }
416 441
417 db_c_close $c; 442 db_c_close $c;
418 443
419 444
420=head3 DB_SEQUENCE/sequence methods 445=head2 DB_SEQUENCE/sequence methods
421 446
422Methods available on DB_SEQUENCE/$seq handles: 447Methods available on DB_SEQUENCE/$seq handles:
423 448
424 DESTROY (DB_SEQUENCE_ornull *seq) 449 DESTROY (DB_SEQUENCE_ornull *seq)
425 CODE: 450 CODE:
… …
430 $int = $seq->set_cachesize (U32 size) 455 $int = $seq->set_cachesize (U32 size)
431 $int = $seq->set_flags (U32 flags) 456 $int = $seq->set_flags (U32 flags)
432 flags: SEQ_DEC SEQ_INC SEQ_WRAP 457 flags: SEQ_DEC SEQ_INC SEQ_WRAP
433 $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)
434 459
435=head4 Example: 460=head3 Example:
436 461
437 my $seq = $db->sequence; 462 my $seq = $db->sequence;
438 463
439 db_sequence_open $seq, undef, "seq", BDB::CREATE; 464 db_sequence_open $seq, undef, "seq", BDB::CREATE;
440 db_sequence_get $seq, undef, 1, my $value; 465 db_sequence_get $seq, undef, 1, my $value;
441 466
442 467
443=head2 SUPPORT FUNCTIONS 468=head1 SUPPORT FUNCTIONS
444 469
445=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 470=head2 EVENT PROCESSING AND EVENT LOOP INTEGRATION
446 471
447=over 4 472=over 4
448 473
449=item $msg = BDB::strerror [$errno] 474=item $msg = BDB::strerror [$errno]
450 475
… …
537 BDB::poll_wait, BDB::poll_cb 562 BDB::poll_wait, BDB::poll_cb
538 while BDB::nreqs; 563 while BDB::nreqs;
539 564
540=back 565=back
541 566
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
542=head3 CONTROLLING THE NUMBER OF THREADS 633=head2 CONTROLLING THE NUMBER OF THREADS
543 634
544=over 4 635=over 4
545 636
546=item BDB::min_parallel $nthreads 637=item BDB::min_parallel $nthreads
547 638
… …
608 699
609You can still queue as many requests as you want. Therefore, 700You can still queue as many requests as you want. Therefore,
610C<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
611as 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).
612 703
613=item BDB::set_sync_prepare $cb 704=item $old_cb = BDB::set_sync_prepare $cb
614 705
615Sets a callback that is called whenever a request is created without an 706Sets a callback that is called whenever a request is created without an
616explicit callback. It has to return two code references. The first is used 707explicit callback. It has to return two code references. The first is used
617as the request callback, and the second is called to wait until the first 708as the request callback (it should save the return status), and the second
618callback has been called. The default implementation works like this: 709is called to wait until the first callback has been called (it must set
710C<$!> 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:
619 717
620 sub { 718 sub {
621 my $status; 719 my $status;
622 ( 720 (
623 sub { $status = $! }, 721 sub { $status = $! },
624 sub { BDB::poll while !defined $status; $! = $status }, 722 sub { BDB::poll while !defined $status; $! = $status },
625 ) 723 )
626 } 724 }
627 725
726It works by polling for results till the request has finished and then
727sets C<$!> 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
628=back 734=back
629 735
630=head3 STATISTICAL INFORMATION 736=head2 STATISTICAL INFORMATION
631 737
632=over 4 738=over 4
633 739
634=item BDB::nreqs 740=item BDB::nreqs
635 741
… …
653 759
654=back 760=back
655 761
656=cut 762=cut
657 763
658set_sync_prepare { 764set_sync_prepare (undef);
659 my $status;
660 (
661 sub {
662 $status = $!;
663 },
664 sub {
665 BDB::poll while !defined $status;
666 $! = $status;
667 },
668 )
669};
670 765
671min_parallel 8; 766min_parallel 8;
672 767
673END { flush } 768END { flush }
674 769
6751; 7701;
676 771
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
677=head2 FORK BEHAVIOUR 795=head1 FORK BEHAVIOUR
678 796
679This 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:
680 798
681Before the fork, BDB enters a quiescent state where no requests 799Before the fork, BDB enters a quiescent state where no requests
682can 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
… …
692 810
693Win32 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
694broken 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
695yet, switch to a more capable platform. 813yet, switch to a more capable platform.
696 814
697=head2 MEMORY USAGE 815=head1 MEMORY USAGE
698 816
699Per-request usage: 817Per-request usage:
700 818
701Each aio request uses - depending on your architecture - around 100-200 819Each aio request uses - depending on your architecture - around 100-200
702bytes of memory. In addition, stat requests need a stat buffer (possibly 820bytes of memory. In addition, stat requests need a stat buffer (possibly
… …
711 829
712In the execution phase, some aio requests require more memory for 830In the execution phase, some aio requests require more memory for
713temporary buffers, and each thread requires a stack and other data 831temporary buffers, and each thread requires a stack and other data
714structures (usually around 16k-128k, depending on the OS). 832structures (usually around 16k-128k, depending on the OS).
715 833
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
716=head1 KNOWN BUGS 843=head1 KNOWN BUGS
717 844
718Known bugs will be fixed in the next release, except: 845Known bugs will be fixed in the next release, except:
719 846
720 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
… …
722 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>,
723 above. 850 above.
724 851
725=head1 SEE ALSO 852=head1 SEE ALSO
726 853
727L<Coro::BDB>, L<IO::AIO>. 854L<AnyEvent::BDB> (event loop integration), L<Coro::BDB> (more natural
855syntax), L<IO::AIO> (nice to have).
728 856
729=head1 AUTHOR 857=head1 AUTHOR
730 858
731 Marc Lehmann <schmorp@schmorp.de> 859 Marc Lehmann <schmorp@schmorp.de>
732 http://home.schmorp.de/ 860 http://home.schmorp.de/

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