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Comparing BDB/BDB.pm (file contents):
Revision 1.38 by root, Mon Jul 7 22:11:04 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
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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 db_env_dbrename db_env_dbremove 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<$!> will reflect the return value
… …
160In the following, C<$int> signifies an integer return value, 153In the following, C<$int> signifies an integer return value,
161C<bdb_filename> is a "filename" (octets on unix, madness on windows), 154C<bdb_filename> is a "filename" (octets on unix, madness on windows),
162C<U32> is an unsigned 32 bit integer, C<int> is some integer, C<NV> is a 155C<U32> is an unsigned 32 bit integer, C<int> is some integer, C<NV> is a
163floating 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, bdb_filename 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)
190 db_env_dbremove (DB_ENV *env, DB_TXN_ornull *txnid, bdb_filename file, bdb_filename database, U32 flags = 0, SV *callback = &PL_sv_undef) 205 db_env_dbremove (DB_ENV *env, DB_TXN_ornull *txnid, bdb_filename file, bdb_filename database, U32 flags = 0, SV *callback = 0)
191 db_env_dbrename (DB_ENV *env, DB_TXN_ornull *txnid, bdb_filename file, bdb_filename database, bdb_filename newname, U32 flags = 0, SV *callback = &PL_sv_undef) 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)
192 210
193 $db = db_create (DB_ENV *env = 0, U32 flags = 0) 211 $db = db_create (DB_ENV *env = 0, U32 flags = 0)
194 flags: XA_CREATE 212 flags: XA_CREATE
195 213
196 db_open (DB *db, DB_TXN_ornull *txnid, bdb_filename file, bdb_filename 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)
197 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
198 db_close (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) 216 db_close (DB *db, U32 flags = 0, SV *callback = 0)
199 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)
200 db_upgrade (DB *db, bdb_filename file, U32 flags = 0, SV *callback = &PL_sv_undef) 219 db_upgrade (DB *db, bdb_filename file, U32 flags = 0, SV *callback = 0)
201 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)
202 flags: FREELIST_ONLY FREE_SPACE 221 flags: FREELIST_ONLY FREE_SPACE
203 db_sync (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) 222 db_sync (DB *db, U32 flags = 0, SV *callback = 0)
204 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)
205 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)
206 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)
207 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)
208 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
209 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)
210 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
211 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)
212 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)
213 flags: TXN_NOSYNC TXN_SYNC 233 flags: TXN_NOSYNC TXN_SYNC
214 db_txn_abort (DB_TXN *txn, SV *callback = &PL_sv_undef) 234 db_txn_abort (DB_TXN *txn, SV *callback = 0)
215 235
216 db_c_close (DBC *dbc, SV *callback = &PL_sv_undef) 236 db_c_close (DBC *dbc, SV *callback = 0)
217 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)
218 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)
219 flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA 239 flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA
220 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)
221 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
222 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)
223 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)
224 244
225 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)
226 flags: CREATE EXCL 246 flags: CREATE EXCL
227 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)
228 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)
229 flags: TXN_NOSYNC 249 flags: TXN_NOSYNC
230 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)
231 flags: TXN_NOSYNC 251 flags: TXN_NOSYNC
232 252
233=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)
234 254
235This is not actually a Berkeley DB function but a BDB module 255This is not actually a Berkeley DB function but a BDB module
236extension. The background for this exytension is: It is very annoying to 256extension. The background for this exytension is: It is very annoying to
237have 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
238codepath out of your transaction. While the BDB module still makes this 258codepath out of your transaction. While the BDB module still makes this
… …
264 284
265You can use the C<< $txn->failed >> method to check wether a transaction 285You can use the C<< $txn->failed >> method to check wether a transaction
266has failed in this way and abort further processing (excluding 286has failed in this way and abort further processing (excluding
267C<db_txn_finish>). 287C<db_txn_finish>).
268 288
289
269=head3 DB_ENV/database environment methods 290=head2 DB_ENV/database environment methods
270 291
271Methods available on DB_ENV/$env handles: 292Methods available on DB_ENV/$env handles:
272 293
273 DESTROY (DB_ENV_ornull *env) 294 DESTROY (DB_ENV_ornull *env)
274 CODE: 295 CODE:
… …
278 $int = $env->set_data_dir (const char *dir) 299 $int = $env->set_data_dir (const char *dir)
279 $int = $env->set_tmp_dir (const char *dir) 300 $int = $env->set_tmp_dir (const char *dir)
280 $int = $env->set_lg_dir (const char *dir) 301 $int = $env->set_lg_dir (const char *dir)
281 $int = $env->set_shm_key (long shm_key) 302 $int = $env->set_shm_key (long shm_key)
282 $int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0) 303 $int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0)
283 $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)
284 $env->set_errfile (FILE *errfile = 0) 307 $env->set_errfile (FILE *errfile = 0)
285 $env->set_msgfile (FILE *msgfile = 0) 308 $env->set_msgfile (FILE *msgfile = 0)
286 $int = $env->set_verbose (U32 which, int onoff = 1) 309 $int = $env->set_verbose (U32 which, int onoff = 1)
287 $int = $env->set_encrypt (const char *password, U32 flags = 0) 310 $int = $env->set_encrypt (const char *password, U32 flags = 0)
288 $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)
… …
300 $int = $env->mutex_set_max (U32 max) 323 $int = $env->mutex_set_max (U32 max)
301 $int = $env->mutex_set_align (U32 align) 324 $int = $env->mutex_set_align (U32 align)
302 325
303 $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)
304 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)
305 329
306=head4 Example: 330=head3 Example:
307 331
308 use AnyEvent; 332 use AnyEvent;
309 use BDB; 333 use BDB;
310 334
311 our $FH; open $FH, "<&=" . BDB::poll_fileno; 335 our $FH; open $FH, "<&=" . BDB::poll_fileno;
… …
323 0600; 347 0600;
324 348
325 $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1); 349 $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1);
326 350
327 351
328=head3 DB/database methods 352=head2 DB/database methods
329 353
330Methods available on DB/$db handles: 354Methods available on DB/$db handles:
331 355
332 DESTROY (DB_ornull *db) 356 DESTROY (DB_ornull *db)
333 CODE: 357 CODE:
… …
359 383
360 $dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0) 384 $dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0)
361 flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT 385 flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT
362 $seq = $db->sequence (U32 flags = 0) 386 $seq = $db->sequence (U32 flags = 0)
363 387
364=head4 Example: 388=head3 Example:
365 389
366 my $db = db_create $env; 390 my $db = db_create $env;
367 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;
368 392
369 for (1..1000) { 393 for (1..1000) {
… …
376 db_del $db, undef, "key $_" for 1..1000; 400 db_del $db, undef, "key $_" for 1..1000;
377 401
378 db_sync $db; 402 db_sync $db;
379 403
380 404
381=head3 DB_TXN/transaction methods 405=head2 DB_TXN/transaction methods
382 406
383Methods available on DB_TXN/$txn handles: 407Methods available on DB_TXN/$txn handles:
384 408
385 DESTROY (DB_TXN_ornull *txn) 409 DESTROY (DB_TXN_ornull *txn)
386 CODE: 410 CODE:
… …
392 416
393 $bool = $txn->failed 417 $bool = $txn->failed
394 # see db_txn_finish documentation, above 418 # see db_txn_finish documentation, above
395 419
396 420
397=head3 DBC/cursor methods 421=head2 DBC/cursor methods
398 422
399Methods available on DBC/$dbc handles: 423Methods available on DBC/$dbc handles:
400 424
401 DESTROY (DBC_ornull *dbc) 425 DESTROY (DBC_ornull *dbc)
402 CODE: 426 CODE:
403 if (dbc) 427 if (dbc)
404 dbc->c_close (dbc); 428 dbc->c_close (dbc);
405 429
406 $int = $cursor->set_priority ($priority = PRIORITY_*) 430 $int = $cursor->set_priority ($priority = PRIORITY_*) (v4.6)
407 431
408=head4 Example: 432=head3 Example:
409 433
410 my $c = $db->cursor; 434 my $c = $db->cursor;
411 435
412 for (;;) { 436 for (;;) {
413 db_c_get $c, my $key, my $data, BDB::NEXT; 437 db_c_get $c, my $key, my $data, BDB::NEXT;
… …
416 } 440 }
417 441
418 db_c_close $c; 442 db_c_close $c;
419 443
420 444
421=head3 DB_SEQUENCE/sequence methods 445=head2 DB_SEQUENCE/sequence methods
422 446
423Methods available on DB_SEQUENCE/$seq handles: 447Methods available on DB_SEQUENCE/$seq handles:
424 448
425 DESTROY (DB_SEQUENCE_ornull *seq) 449 DESTROY (DB_SEQUENCE_ornull *seq)
426 CODE: 450 CODE:
… …
431 $int = $seq->set_cachesize (U32 size) 455 $int = $seq->set_cachesize (U32 size)
432 $int = $seq->set_flags (U32 flags) 456 $int = $seq->set_flags (U32 flags)
433 flags: SEQ_DEC SEQ_INC SEQ_WRAP 457 flags: SEQ_DEC SEQ_INC SEQ_WRAP
434 $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)
435 459
436=head4 Example: 460=head3 Example:
437 461
438 my $seq = $db->sequence; 462 my $seq = $db->sequence;
439 463
440 db_sequence_open $seq, undef, "seq", BDB::CREATE; 464 db_sequence_open $seq, undef, "seq", BDB::CREATE;
441 db_sequence_get $seq, undef, 1, my $value; 465 db_sequence_get $seq, undef, 1, my $value;
442 466
443 467
444=head2 SUPPORT FUNCTIONS 468=head1 SUPPORT FUNCTIONS
445 469
446=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION 470=head2 EVENT PROCESSING AND EVENT LOOP INTEGRATION
447 471
448=over 4 472=over 4
449 473
450=item $msg = BDB::strerror [$errno] 474=item $msg = BDB::strerror [$errno]
451 475
… …
538 BDB::poll_wait, BDB::poll_cb 562 BDB::poll_wait, BDB::poll_cb
539 while BDB::nreqs; 563 while BDB::nreqs;
540 564
541=back 565=back
542 566
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
543=head3 CONTROLLING THE NUMBER OF THREADS 633=head2 CONTROLLING THE NUMBER OF THREADS
544 634
545=over 4 635=over 4
546 636
547=item BDB::min_parallel $nthreads 637=item BDB::min_parallel $nthreads
548 638
… …
609 699
610You can still queue as many requests as you want. Therefore, 700You can still queue as many requests as you want. Therefore,
611C<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
612as 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).
613 703
614=item BDB::set_sync_prepare $cb 704=item $old_cb = BDB::set_sync_prepare $cb
615 705
616Sets a callback that is called whenever a request is created without an 706Sets a callback that is called whenever a request is created without an
617explicit callback. It has to return two code references. The first is used 707explicit callback. It has to return two code references. The first is used
618as the request callback (it should save the return status), and the second 708as the request callback (it should save the return status), and the second
619is called to wait until the first callback has been called (it must set 709is called to wait until the first callback has been called (it must set
620C<$!> to the return status). 710C<$!> to the return status).
621 711
622This mechanism can be used to include BDB into other event mechanisms, 712This mechanism can be used to include BDB into other event mechanisms,
623such as L<AnyEvent::BDB> or L<Coro::BDB>. 713such as L<Coro::BDB>.
624 714
625The 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:
626 717
627 sub { 718 sub {
628 my $status; 719 my $status;
629 ( 720 (
630 sub { $status = $! }, 721 sub { $status = $! },
631 sub { BDB::poll while !defined $status; $! = $status }, 722 sub { BDB::poll while !defined $status; $! = $status },
632 ) 723 )
633 } 724 }
634 725
635It simply blocks the process till the request has finished and then sets 726It works by polling for results till the request has finished and then
636C<$!> to the return value. This means that if you don't use a callback, 727sets C<$!> to the return value. This means that if you don't use a
637BDB will simply fall back to synchronous operations. 728callback, BDB would simply fall back to synchronous operations.
729
730By default, or if the sync prepare function is set to C<undef>, is to
731execute callback-less BDB requests in the foreground thread, setting C<$!>
732to the return value, without polling for other events.
638 733
639=back 734=back
640 735
641=head3 STATISTICAL INFORMATION 736=head2 STATISTICAL INFORMATION
642 737
643=over 4 738=over 4
644 739
645=item BDB::nreqs 740=item BDB::nreqs
646 741
… …
664 759
665=back 760=back
666 761
667=cut 762=cut
668 763
669set_sync_prepare { 764set_sync_prepare (undef);
670 my $status;
671 (
672 sub {
673 $status = $!;
674 },
675 sub {
676 BDB::poll while !defined $status;
677 $! = $status;
678 },
679 )
680};
681 765
682min_parallel 8; 766min_parallel 8;
683 767
684END { flush } 768END { flush }
685 769
6861; 7701;
687 771
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
688=head2 FORK BEHAVIOUR 795=head1 FORK BEHAVIOUR
689 796
690This 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:
691 798
692Before the fork, BDB enters a quiescent state where no requests 799Before the fork, BDB enters a quiescent state where no requests
693can 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
… …
703 810
704Win32 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
705broken 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
706yet, switch to a more capable platform. 813yet, switch to a more capable platform.
707 814
708=head2 MEMORY USAGE 815=head1 MEMORY USAGE
709 816
710Per-request usage: 817Per-request usage:
711 818
712Each aio request uses - depending on your architecture - around 100-200 819Each aio request uses - depending on your architecture - around 100-200
713bytes of memory. In addition, stat requests need a stat buffer (possibly 820bytes of memory. In addition, stat requests need a stat buffer (possibly
… …
722 829
723In the execution phase, some aio requests require more memory for 830In the execution phase, some aio requests require more memory for
724temporary buffers, and each thread requires a stack and other data 831temporary buffers, and each thread requires a stack and other data
725structures (usually around 16k-128k, depending on the OS). 832structures (usually around 16k-128k, depending on the OS).
726 833
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
727=head1 KNOWN BUGS 843=head1 KNOWN BUGS
728 844
729Known bugs will be fixed in the next release, except: 845Known bugs will be fixed in the next release, except:
730 846
731 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

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