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Comparing BDB/BDB.pm (file contents):
Revision 1.14 by root, Thu Sep 13 12:29:49 2007 UTC vs.
Revision 1.17 by root, Tue Dec 4 10:13:50 2007 UTC

… …
72use strict 'vars'; 72use strict 'vars';
73 73
74use base 'Exporter'; 74use base 'Exporter';
75 75
76BEGIN { 76BEGIN {
77 our $VERSION = '1.0'; 77 our $VERSION = '1.2';
78 78
79 our @BDB_REQ = qw( 79 our @BDB_REQ = qw(
80 db_env_open db_env_close db_env_txn_checkpoint db_env_lock_detect 80 db_env_open db_env_close db_env_txn_checkpoint db_env_lock_detect
81 db_env_memp_sync db_env_memp_trickle 81 db_env_memp_sync db_env_memp_trickle
82 db_open db_close db_compact db_sync db_put db_get db_pget db_del db_key_range 82 db_open db_close db_compact db_sync db_put db_get db_pget db_del db_key_range
83 db_txn_commit db_txn_abort 83 db_txn_commit db_txn_abort db_txn_finish
84 db_c_close db_c_count db_c_put db_c_get db_c_pget db_c_del 84 db_c_close db_c_count db_c_put db_c_get db_c_pget db_c_del
85 db_sequence_open db_sequence_close 85 db_sequence_open db_sequence_close
86 db_sequence_get db_sequence_remove 86 db_sequence_get db_sequence_remove
87 ); 87 );
88 our @EXPORT = (@BDB_REQ, qw(dbreq_pri dbreq_nice db_env_create db_create)); 88 our @EXPORT = (@BDB_REQ, qw(dbreq_pri dbreq_nice db_env_create db_create));
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177 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) 177 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)
178 flags: TXN_NOSYNC 178 flags: TXN_NOSYNC
179 db_sequence_remove (DB_SEQUENCE *seq, DB_TXN_ornull *txnid = 0, U32 flags = 0, SV *callback = &PL_sv_undef) 179 db_sequence_remove (DB_SEQUENCE *seq, DB_TXN_ornull *txnid = 0, U32 flags = 0, SV *callback = &PL_sv_undef)
180 flags: TXN_NOSYNC 180 flags: TXN_NOSYNC
181 181
182=head4 db_txn_finish (DB_TXN *txn, U32 flags = 0, SV *callback = &PL_sv_undef)
183
184This is not actually a Berkeley DB function but a BDB module
185extension. The background for this exytension is: It is very annoying to
186have to check every single BDB function for error returns and provide a
187codepath out of your transaction. While the BDB module still makes this
188possible, it contains the following extensions:
189
190When a transaction-protected function returns any operating system
191error (errno > 0), BDB will set the C<TXN_DEADLOCK> flag on the
192transaction. This flag is also set by Berkeley DB functions themselves
193when an operation fails with LOCK_DEADLOCK, and it causes all further
194operations on that transaction (including C<db_txn_commit>) to fail.
195
196The C<db_txn_finish> request will look at this flag, and, if it is set,
197will automatically call C<db_txn_abort> (setting errno to C<LOCK_DEADLOCK>
198if it isn't set to something else yet). If it isn't set, it will call
199C<db_txn_commit> and return the error normally.
200
201How to use this? Easy: just write your transaction normally:
202
203 my $txn = $db_env->txn_begin;
204 db_get $db, $txn, "key", my $data;
205 db_put $db, $txn, "key", $data + 1 unless $! == BDB::NOTFOUND;
206 db_txn_finish $txn;
207 die "transaction failed" if $!;
208
209That is, handle only the expected errors. If something unexpected happens
210(EIO, LOCK_NOTGRANTED or a deadlock in either db_get or db_put), then the remaining
211requests (db_put in this case) will simply be skipped (they will fail with
212LOCK_DEADLOCK) and the transaction will be aborted.
213
214You can use the C<< $txn->failed >> method to check wether a transaction
215has failed in this way and abort further processing (excluding
216C<db_txn_finish>).
217
182=head3 DB_ENV/database environment methods 218=head3 DB_ENV/database environment methods
183 219
184Methods available on DB_ENV/$env handles: 220Methods available on DB_ENV/$env handles:
185 221
186 DESTROY (DB_ENV_ornull *env) 222 DESTROY (DB_ENV_ornull *env)
… …
196 $int = $env->set_flags (U32 flags, int onoff) 232 $int = $env->set_flags (U32 flags, int onoff)
197 $env->set_errfile (FILE *errfile = 0) 233 $env->set_errfile (FILE *errfile = 0)
198 $env->set_msgfile (FILE *msgfile = 0) 234 $env->set_msgfile (FILE *msgfile = 0)
199 $int = $env->set_verbose (U32 which, int onoff = 1) 235 $int = $env->set_verbose (U32 which, int onoff = 1)
200 $int = $env->set_encrypt (const char *password, U32 flags = 0) 236 $int = $env->set_encrypt (const char *password, U32 flags = 0)
201 $int = $env->set_timeout (NV timeout, U32 flags) 237 $int = $env->set_timeout (NV timeout_seconds, U32 flags = SET_TXN_TIMEOUT)
202 $int = $env->set_mp_max_openfd (int maxopenfd); 238 $int = $env->set_mp_max_openfd (int maxopenfd);
203 $int = $env->set_mp_max_write (int maxwrite, int maxwrite_sleep); 239 $int = $env->set_mp_max_write (int maxwrite, int maxwrite_sleep);
204 $int = $env->set_mp_mmapsize (int mmapsize_mb) 240 $int = $env->set_mp_mmapsize (int mmapsize_mb)
205 $int = $env->set_lk_detect (U32 detect = DB_LOCK_DEFAULT) 241 $int = $env->set_lk_detect (U32 detect = DB_LOCK_DEFAULT)
206 $int = $env->set_lk_max_lockers (U32 max) 242 $int = $env->set_lk_max_lockers (U32 max)
… …
294 DESTROY (DB_TXN_ornull *txn) 330 DESTROY (DB_TXN_ornull *txn)
295 CODE: 331 CODE:
296 if (txn) 332 if (txn)
297 txn->abort (txn); 333 txn->abort (txn);
298 334
299 $int = $txn->set_timeout (NV timeout, U32 flags) 335 $int = $txn->set_timeout (NV timeout_seconds, U32 flags = SET_TXN_TIMEOUT)
300 flags: SET_LOCK_TIMEOUT SET_TXN_TIMEOUT 336 flags: SET_LOCK_TIMEOUT SET_TXN_TIMEOUT
337
338 $bool = $txn->failed
339 # see db_txn_finish documentation, above
301 340
302 341
303=head3 DBC/cursor methods 342=head3 DBC/cursor methods
304 343
305Methods available on DBC/$dbc handles: 344Methods available on DBC/$dbc handles:
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609temporary buffers, and each thread requires a stack and other data 648temporary buffers, and each thread requires a stack and other data
610structures (usually around 16k-128k, depending on the OS). 649structures (usually around 16k-128k, depending on the OS).
611 650
612=head1 KNOWN BUGS 651=head1 KNOWN BUGS
613 652
614Known bugs will be fixed in the next release. 653Known bugs will be fixed in the next release, except:
654
655 If you use a transaction in any request, and the request returns
656 with an operating system error or DB_LOCK_NOTGRANTED, the internal
657 TXN_DEADLOCK flag will be set on the transaction. See C<db_txn_finish>,
658 above.
615 659
616=head1 SEE ALSO 660=head1 SEE ALSO
617 661
618L<Coro::AIO>. 662L<Coro::AIO>.
619 663

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