… | |
… | |
25 | db_sync $db; |
25 | db_sync $db; |
26 | |
26 | |
27 | # when you also use Coro, management is easy: |
27 | # when you also use Coro, management is easy: |
28 | use Coro::BDB; |
28 | use Coro::BDB; |
29 | |
29 | |
30 | # automatic event loop intergration with AnyEvent: |
30 | # automatic event loop integration with AnyEvent: |
31 | use AnyEvent::BDB; |
31 | use AnyEvent::BDB; |
32 | |
32 | |
33 | # automatic result processing with EV: |
33 | # automatic result processing with EV: |
34 | my $WATCHER = EV::io BDB::poll_fileno, EV::READ, \&BDB::poll_cb; |
34 | my $WATCHER = EV::io BDB::poll_fileno, EV::READ, \&BDB::poll_cb; |
35 | |
35 | |
… | |
… | |
86 | Request has reached the end of its lifetime and holds no resources |
86 | Request has reached the end of its lifetime and holds no resources |
87 | anymore (except possibly for the Perl object, but its connection to |
87 | anymore (except possibly for the Perl object, but its connection to |
88 | the actual aio request is severed and calling its methods will |
88 | the actual aio request is severed and calling its methods will |
89 | either do nothing or result in a runtime error). |
89 | either do nothing or result in a runtime error). |
90 | |
90 | |
91 | WIN32 FILENAMES/DATABASE NAME MESS |
|
|
92 | Perl on Win32 supports only ASCII filenames (the reason is that it |
|
|
93 | abuses an internal flag to store wether a filename is Unicode or ANSI, |
|
|
94 | but that flag is used for somethign else in the perl core, so there is |
|
|
95 | no way to detect wether a filename is ANSI or Unicode-encoded). The BDB |
|
|
96 | module tries to work around this issue by assuming that the filename is |
|
|
97 | an ANSI filename and BDB was built for unicode support. |
|
|
98 | |
|
|
99 | BERKELEYDB FUNCTIONS |
91 | BERKELEYDB FUNCTIONS |
100 | All of these are functions. The create functions simply return a new |
92 | All of these are functions. The create functions simply return a new |
101 | object and never block. All the remaining functions take an optional |
93 | object and never block. All the remaining functions take an optional |
102 | callback as last argument. If it is missing, then the function will be |
94 | callback as last argument. If it is missing, then the function will be |
103 | executed synchronously. In both cases, $! will reflect the return value |
95 | executed synchronously. In both cases, $! will reflect the return value |
104 | of the function. |
96 | of the function. |
… | |
… | |
106 | BDB functions that cannot block (mostly functions that manipulate |
98 | BDB functions that cannot block (mostly functions that manipulate |
107 | settings) are method calls on the relevant objects, so the rule of thumb |
99 | settings) are method calls on the relevant objects, so the rule of thumb |
108 | is: if it's a method, it's not blocking, if it's a function, it takes a |
100 | is: if it's a method, it's not blocking, if it's a function, it takes a |
109 | callback as last argument. |
101 | callback as last argument. |
110 | |
102 | |
111 | In the following, $int signifies an integer return value, "octetstring" |
103 | In the following, $int signifies an integer return value, "bdb_filename" |
112 | is a "binary string" (i.e. a perl string with no character indices |
104 | is a "filename" (octets on unix, madness on windows), "U32" is an |
113 | >255), "U32" is an unsigned 32 bit integer, "int" is some integer, "NV" |
105 | unsigned 32 bit integer, "int" is some integer, "NV" is a floating point |
114 | is a floating point value. |
106 | value. |
115 | |
107 | |
116 | The "SV *" types are generic perl scalars (for input and output of data |
108 | Most "SV *" types are generic perl scalars (for input and output of data |
117 | values), and the "SV *callback" is the optional callback function to |
109 | values). |
118 | call when the request is completed. |
|
|
119 | |
110 | |
120 | The various "DB_ENV" etc. arguments are handles return by |
111 | The various "DB_ENV" etc. arguments are handles return by |
121 | "db_env_create", "db_create", "txn_begin" and so on. If they have an |
112 | "db_env_create", "db_create", "txn_begin" and so on. If they have an |
122 | appended "_ornull" this means they are optional and you can pass "undef" |
113 | appended "_ornull" this means they are optional and you can pass "undef" |
123 | for them, resulting a NULL pointer on the C level. |
114 | for them, resulting a NULL pointer on the C level. |
124 | |
115 | |
|
|
116 | The "SV *callback" is the optional callback function to call when the |
|
|
117 | request is completed. This last callback argument is special: the |
|
|
118 | callback is simply the last argument passed. If there are "optional" |
|
|
119 | arguments before the callback they can be left out. The callback itself |
|
|
120 | can be left out or specified as "undef", in which case the function will |
|
|
121 | be executed synchronously. |
|
|
122 | |
|
|
123 | For example, "db_env_txn_checkpoint" usually is called with all integer |
|
|
124 | arguments zero. These can be left out, so all of these specify a call to |
|
|
125 | "DB_ENV->txn_checkpoint", to be executed asynchronously with a callback |
|
|
126 | to be called: |
|
|
127 | |
|
|
128 | db_env_txn_checkpoint $db_env, 0, 0, 0, sub { }; |
|
|
129 | db_env_txn_checkpoint $db_env, 0, 0, sub { }; |
|
|
130 | db_env_txn_checkpoint $db_env, sub { }; |
|
|
131 | |
|
|
132 | While these all specify a call to "DB_ENV->txn_checkpoint" to be |
|
|
133 | executed synchronously: |
|
|
134 | |
|
|
135 | db_env_txn_checkpoint $db_env, 0, 0, 0, undef; |
|
|
136 | db_env_txn_checkpoint $db_env, 0, 0, 0; |
|
|
137 | db_env_txn_checkpoint $db_env, 0; |
|
|
138 | |
125 | BDB functions |
139 | BDB functions |
126 | Functions in the BDB namespace, exported by default: |
140 | Functions in the BDB namespace, exported by default: |
127 | |
141 | |
128 | $env = db_env_create (U32 env_flags = 0) |
142 | $env = db_env_create (U32 env_flags = 0) |
129 | flags: RPCCLIENT |
143 | flags: RPCCLIENT |
130 | |
144 | |
131 | db_env_open (DB_ENV *env, octetstring db_home, U32 open_flags, int mode, SV *callback = &PL_sv_undef) |
145 | db_env_open (DB_ENV *env, bdb_filename db_home, U32 open_flags, int mode, SV *callback = 0) |
132 | 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 |
146 | 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 |
133 | db_env_close (DB_ENV *env, U32 flags = 0, SV *callback = &PL_sv_undef) |
147 | db_env_close (DB_ENV *env, U32 flags = 0, SV *callback = 0) |
134 | db_env_txn_checkpoint (DB_ENV *env, U32 kbyte = 0, U32 min = 0, U32 flags = 0, SV *callback = &PL_sv_undef) |
148 | db_env_txn_checkpoint (DB_ENV *env, U32 kbyte = 0, U32 min = 0, U32 flags = 0, SV *callback = 0) |
135 | flags: FORCE |
149 | flags: FORCE |
136 | db_env_lock_detect (DB_ENV *env, U32 flags = 0, U32 atype = DB_LOCK_DEFAULT, SV *dummy = 0, SV *callback = &PL_sv_undef) |
150 | db_env_lock_detect (DB_ENV *env, U32 flags = 0, U32 atype = DB_LOCK_DEFAULT, SV *dummy = 0, SV *callback = 0) |
137 | atype: LOCK_DEFAULT LOCK_EXPIRE LOCK_MAXLOCKS LOCK_MAXWRITE LOCK_MINLOCKS LOCK_MINWRITE LOCK_OLDEST LOCK_RANDOM LOCK_YOUNGEST |
151 | atype: LOCK_DEFAULT LOCK_EXPIRE LOCK_MAXLOCKS LOCK_MAXWRITE LOCK_MINLOCKS LOCK_MINWRITE LOCK_OLDEST LOCK_RANDOM LOCK_YOUNGEST |
138 | db_env_memp_sync (DB_ENV *env, SV *dummy = 0, SV *callback = &PL_sv_undef) |
152 | db_env_memp_sync (DB_ENV *env, SV *dummy = 0, SV *callback = 0) |
139 | db_env_memp_trickle (DB_ENV *env, int percent, SV *dummy = 0, SV *callback = &PL_sv_undef) |
153 | db_env_memp_trickle (DB_ENV *env, int percent, SV *dummy = 0, SV *callback = 0) |
|
|
154 | db_env_dbremove (DB_ENV *env, DB_TXN_ornull *txnid, bdb_filename file, bdb_filename database, U32 flags = 0, SV *callback = 0) |
|
|
155 | 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) |
|
|
156 | db_env_log_archive (DB_ENV *env, SV *listp, U32 flags = 0, SV *callback = 0) |
140 | |
157 | |
141 | $db = db_create (DB_ENV *env = 0, U32 flags = 0) |
158 | $db = db_create (DB_ENV *env = 0, U32 flags = 0) |
142 | flags: XA_CREATE |
159 | flags: XA_CREATE |
143 | |
160 | |
144 | db_open (DB *db, DB_TXN_ornull *txnid, octetstring file, octetstring database, int type, U32 flags, int mode, SV *callback = &PL_sv_undef) |
161 | db_open (DB *db, DB_TXN_ornull *txnid, bdb_filename file, bdb_filename database, int type, U32 flags, int mode, SV *callback = 0) |
145 | flags: AUTO_COMMIT CREATE EXCL MULTIVERSION NOMMAP RDONLY READ_UNCOMMITTED THREAD TRUNCATE |
162 | flags: AUTO_COMMIT CREATE EXCL MULTIVERSION NOMMAP RDONLY READ_UNCOMMITTED THREAD TRUNCATE |
146 | db_close (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) |
163 | db_close (DB *db, U32 flags = 0, SV *callback = 0) |
147 | flags: DB_NOSYNC |
164 | flags: DB_NOSYNC |
|
|
165 | db_verify (DB *db, bdb_filename file, bdb_filename database = 0, SV *dummy = 0, U32 flags = 0, SV *callback = 0) |
148 | db_upgrade (DB *db, octetstring file, U32 flags = 0, SV *callback = &PL_sv_undef) |
166 | db_upgrade (DB *db, bdb_filename file, U32 flags = 0, SV *callback = 0) |
149 | 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) |
167 | 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) |
150 | flags: FREELIST_ONLY FREE_SPACE |
168 | flags: FREELIST_ONLY FREE_SPACE |
151 | db_sync (DB *db, U32 flags = 0, SV *callback = &PL_sv_undef) |
169 | db_sync (DB *db, U32 flags = 0, SV *callback = 0) |
152 | db_key_range (DB *db, DB_TXN_ornull *txn, SV *key, SV *key_range, U32 flags = 0, SV *callback = &PL_sv_undef) |
170 | db_key_range (DB *db, DB_TXN_ornull *txn, SV *key, SV *key_range, U32 flags = 0, SV *callback = 0) |
153 | db_put (DB *db, DB_TXN_ornull *txn, SV *key, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) |
171 | db_put (DB *db, DB_TXN_ornull *txn, SV *key, SV *data, U32 flags = 0, SV *callback = 0) |
154 | flags: APPEND NODUPDATA NOOVERWRITE |
172 | flags: APPEND NODUPDATA NOOVERWRITE |
|
|
173 | db_exists (DB *db, DB_TXN_ornull *txn, SV *key, U32 flags = 0, SV *callback = 0) (v4.6) |
155 | db_get (DB *db, DB_TXN_ornull *txn, SV *key, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) |
174 | db_get (DB *db, DB_TXN_ornull *txn, SV *key, SV *data, U32 flags = 0, SV *callback = 0) |
156 | flags: CONSUME CONSUME_WAIT GET_BOTH SET_RECNO MULTIPLE READ_COMMITTED READ_UNCOMMITTED RMW |
175 | flags: CONSUME CONSUME_WAIT GET_BOTH SET_RECNO MULTIPLE READ_COMMITTED READ_UNCOMMITTED RMW |
157 | db_pget (DB *db, DB_TXN_ornull *txn, SV *key, SV *pkey, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) |
176 | db_pget (DB *db, DB_TXN_ornull *txn, SV *key, SV *pkey, SV *data, U32 flags = 0, SV *callback = 0) |
158 | flags: CONSUME CONSUME_WAIT GET_BOTH SET_RECNO MULTIPLE READ_COMMITTED READ_UNCOMMITTED RMW |
177 | flags: CONSUME CONSUME_WAIT GET_BOTH SET_RECNO MULTIPLE READ_COMMITTED READ_UNCOMMITTED RMW |
159 | db_del (DB *db, DB_TXN_ornull *txn, SV *key, U32 flags = 0, SV *callback = &PL_sv_undef) |
178 | db_del (DB *db, DB_TXN_ornull *txn, SV *key, U32 flags = 0, SV *callback = 0) |
160 | db_txn_commit (DB_TXN *txn, U32 flags = 0, SV *callback = &PL_sv_undef) |
179 | db_txn_commit (DB_TXN *txn, U32 flags = 0, SV *callback = 0) |
161 | flags: TXN_NOSYNC TXN_SYNC |
180 | flags: TXN_NOSYNC TXN_SYNC |
162 | db_txn_abort (DB_TXN *txn, SV *callback = &PL_sv_undef) |
181 | db_txn_abort (DB_TXN *txn, SV *callback = 0) |
163 | |
182 | |
164 | db_c_close (DBC *dbc, SV *callback = &PL_sv_undef) |
183 | db_c_close (DBC *dbc, SV *callback = 0) |
165 | db_c_count (DBC *dbc, SV *count, U32 flags = 0, SV *callback = &PL_sv_undef) |
184 | db_c_count (DBC *dbc, SV *count, U32 flags = 0, SV *callback = 0) |
166 | db_c_put (DBC *dbc, SV *key, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) |
185 | db_c_put (DBC *dbc, SV *key, SV *data, U32 flags = 0, SV *callback = 0) |
167 | flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA |
186 | flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA |
168 | db_c_get (DBC *dbc, SV *key, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) |
187 | db_c_get (DBC *dbc, SV *key, SV *data, U32 flags = 0, SV *callback = 0) |
169 | 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 |
188 | 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 |
170 | db_c_pget (DBC *dbc, SV *key, SV *pkey, SV *data, U32 flags = 0, SV *callback = &PL_sv_undef) |
189 | db_c_pget (DBC *dbc, SV *key, SV *pkey, SV *data, U32 flags = 0, SV *callback = 0) |
171 | db_c_del (DBC *dbc, U32 flags = 0, SV *callback = &PL_sv_undef) |
190 | db_c_del (DBC *dbc, U32 flags = 0, SV *callback = 0) |
172 | |
191 | |
173 | db_sequence_open (DB_SEQUENCE *seq, DB_TXN_ornull *txnid, SV *key, U32 flags = 0, SV *callback = &PL_sv_undef) |
192 | db_sequence_open (DB_SEQUENCE *seq, DB_TXN_ornull *txnid, SV *key, U32 flags = 0, SV *callback = 0) |
174 | flags: CREATE EXCL |
193 | flags: CREATE EXCL |
175 | db_sequence_close (DB_SEQUENCE *seq, U32 flags = 0, SV *callback = &PL_sv_undef) |
194 | db_sequence_close (DB_SEQUENCE *seq, U32 flags = 0, SV *callback = 0) |
176 | 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) |
195 | db_sequence_get (DB_SEQUENCE *seq, DB_TXN_ornull *txnid, int delta, SV *seq_value, U32 flags = DB_TXN_NOSYNC, SV *callback = 0) |
177 | flags: TXN_NOSYNC |
196 | flags: TXN_NOSYNC |
178 | db_sequence_remove (DB_SEQUENCE *seq, DB_TXN_ornull *txnid = 0, U32 flags = 0, SV *callback = &PL_sv_undef) |
197 | db_sequence_remove (DB_SEQUENCE *seq, DB_TXN_ornull *txnid = 0, U32 flags = 0, SV *callback = 0) |
179 | flags: TXN_NOSYNC |
198 | flags: TXN_NOSYNC |
180 | |
199 | |
181 | db_txn_finish (DB_TXN *txn, U32 flags = 0, SV *callback = &PL_sv_undef) |
200 | db_txn_finish (DB_TXN *txn, U32 flags = 0, SV *callback = 0) |
182 | This is not actually a Berkeley DB function but a BDB module extension. |
201 | This is not actually a Berkeley DB function but a BDB module extension. |
183 | The background for this exytension is: It is very annoying to have to |
202 | The background for this exytension is: It is very annoying to have to |
184 | check every single BDB function for error returns and provide a codepath |
203 | check every single BDB function for error returns and provide a codepath |
185 | out of your transaction. While the BDB module still makes this possible, |
204 | out of your transaction. While the BDB module still makes this possible, |
186 | it contains the following extensions: |
205 | it contains the following extensions: |
… | |
… | |
211 | |
230 | |
212 | You can use the "$txn->failed" method to check wether a transaction has |
231 | You can use the "$txn->failed" method to check wether a transaction has |
213 | failed in this way and abort further processing (excluding |
232 | failed in this way and abort further processing (excluding |
214 | "db_txn_finish"). |
233 | "db_txn_finish"). |
215 | |
234 | |
216 | DB_ENV/database environment methods |
235 | DB_ENV/database environment methods |
217 | Methods available on DB_ENV/$env handles: |
236 | Methods available on DB_ENV/$env handles: |
218 | |
237 | |
219 | DESTROY (DB_ENV_ornull *env) |
238 | DESTROY (DB_ENV_ornull *env) |
220 | CODE: |
239 | CODE: |
221 | if (env) |
240 | if (env) |
… | |
… | |
224 | $int = $env->set_data_dir (const char *dir) |
243 | $int = $env->set_data_dir (const char *dir) |
225 | $int = $env->set_tmp_dir (const char *dir) |
244 | $int = $env->set_tmp_dir (const char *dir) |
226 | $int = $env->set_lg_dir (const char *dir) |
245 | $int = $env->set_lg_dir (const char *dir) |
227 | $int = $env->set_shm_key (long shm_key) |
246 | $int = $env->set_shm_key (long shm_key) |
228 | $int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0) |
247 | $int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0) |
229 | $int = $env->set_flags (U32 flags, int onoff) |
248 | $int = $env->set_flags (U32 flags, int onoff = 1) |
|
|
249 | $int = $env->log_set_config (U32 flags, int onoff = 1) (v4.7) |
|
|
250 | $int = $env->set_intermediate_dir_mode (const char *modestring) (v4.7) |
230 | $env->set_errfile (FILE *errfile = 0) |
251 | $env->set_errfile (FILE *errfile = 0) |
231 | $env->set_msgfile (FILE *msgfile = 0) |
252 | $env->set_msgfile (FILE *msgfile = 0) |
232 | $int = $env->set_verbose (U32 which, int onoff = 1) |
253 | $int = $env->set_verbose (U32 which, int onoff = 1) |
233 | $int = $env->set_encrypt (const char *password, U32 flags = 0) |
254 | $int = $env->set_encrypt (const char *password, U32 flags = 0) |
234 | $int = $env->set_timeout (NV timeout_seconds, U32 flags = SET_TXN_TIMEOUT) |
255 | $int = $env->set_timeout (NV timeout_seconds, U32 flags = SET_TXN_TIMEOUT) |
… | |
… | |
246 | $int = $env->mutex_set_max (U32 max) |
267 | $int = $env->mutex_set_max (U32 max) |
247 | $int = $env->mutex_set_align (U32 align) |
268 | $int = $env->mutex_set_align (U32 align) |
248 | |
269 | |
249 | $txn = $env->txn_begin (DB_TXN_ornull *parent = 0, U32 flags = 0) |
270 | $txn = $env->txn_begin (DB_TXN_ornull *parent = 0, U32 flags = 0) |
250 | flags: READ_COMMITTED READ_UNCOMMITTED TXN_NOSYNC TXN_NOWAIT TXN_SNAPSHOT TXN_SYNC TXN_WAIT TXN_WRITE_NOSYNC |
271 | flags: READ_COMMITTED READ_UNCOMMITTED TXN_NOSYNC TXN_NOWAIT TXN_SNAPSHOT TXN_SYNC TXN_WAIT TXN_WRITE_NOSYNC |
|
|
272 | $txn = $env->cdsgroup_begin; (v4.5) |
251 | |
273 | |
252 | Example: |
274 | Example: |
253 | use AnyEvent; |
275 | use AnyEvent; |
254 | use BDB; |
276 | use BDB; |
255 | |
277 | |
… | |
… | |
267 | BDB::INIT_LOCK | BDB::INIT_LOG | BDB::INIT_MPOOL | BDB::INIT_TXN | BDB::RECOVER | BDB::USE_ENVIRON | BDB::CREATE, |
289 | BDB::INIT_LOCK | BDB::INIT_LOG | BDB::INIT_MPOOL | BDB::INIT_TXN | BDB::RECOVER | BDB::USE_ENVIRON | BDB::CREATE, |
268 | 0600; |
290 | 0600; |
269 | |
291 | |
270 | $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1); |
292 | $env->set_flags (BDB::AUTO_COMMIT | BDB::TXN_NOSYNC, 1); |
271 | |
293 | |
272 | DB/database methods |
294 | DB/database methods |
273 | Methods available on DB/$db handles: |
295 | Methods available on DB/$db handles: |
274 | |
296 | |
275 | DESTROY (DB_ornull *db) |
297 | DESTROY (DB_ornull *db) |
276 | CODE: |
298 | CODE: |
277 | if (db) |
299 | if (db) |
… | |
… | |
317 | |
339 | |
318 | db_del $db, undef, "key $_" for 1..1000; |
340 | db_del $db, undef, "key $_" for 1..1000; |
319 | |
341 | |
320 | db_sync $db; |
342 | db_sync $db; |
321 | |
343 | |
322 | DB_TXN/transaction methods |
344 | DB_TXN/transaction methods |
323 | Methods available on DB_TXN/$txn handles: |
345 | Methods available on DB_TXN/$txn handles: |
324 | |
346 | |
325 | DESTROY (DB_TXN_ornull *txn) |
347 | DESTROY (DB_TXN_ornull *txn) |
326 | CODE: |
348 | CODE: |
327 | if (txn) |
349 | if (txn) |
… | |
… | |
331 | flags: SET_LOCK_TIMEOUT SET_TXN_TIMEOUT |
353 | flags: SET_LOCK_TIMEOUT SET_TXN_TIMEOUT |
332 | |
354 | |
333 | $bool = $txn->failed |
355 | $bool = $txn->failed |
334 | # see db_txn_finish documentation, above |
356 | # see db_txn_finish documentation, above |
335 | |
357 | |
336 | DBC/cursor methods |
358 | DBC/cursor methods |
337 | Methods available on DBC/$dbc handles: |
359 | Methods available on DBC/$dbc handles: |
338 | |
360 | |
339 | DESTROY (DBC_ornull *dbc) |
361 | DESTROY (DBC_ornull *dbc) |
340 | CODE: |
362 | CODE: |
341 | if (dbc) |
363 | if (dbc) |
342 | dbc->c_close (dbc); |
364 | dbc->c_close (dbc); |
343 | |
365 | |
344 | $int = $cursor->set_priority ($priority = PRIORITY_*) |
366 | $int = $cursor->set_priority ($priority = PRIORITY_*) (v4.6) |
345 | |
367 | |
346 | Example: |
368 | Example: |
347 | my $c = $db->cursor; |
369 | my $c = $db->cursor; |
348 | |
370 | |
349 | for (;;) { |
371 | for (;;) { |
… | |
… | |
352 | last if $!; |
374 | last if $!; |
353 | } |
375 | } |
354 | |
376 | |
355 | db_c_close $c; |
377 | db_c_close $c; |
356 | |
378 | |
357 | DB_SEQUENCE/sequence methods |
379 | DB_SEQUENCE/sequence methods |
358 | Methods available on DB_SEQUENCE/$seq handles: |
380 | Methods available on DB_SEQUENCE/$seq handles: |
359 | |
381 | |
360 | DESTROY (DB_SEQUENCE_ornull *seq) |
382 | DESTROY (DB_SEQUENCE_ornull *seq) |
361 | CODE: |
383 | CODE: |
362 | if (seq) |
384 | if (seq) |
… | |
… | |
368 | flags: SEQ_DEC SEQ_INC SEQ_WRAP |
390 | flags: SEQ_DEC SEQ_INC SEQ_WRAP |
369 | $int = $seq->set_range (db_seq_t min, db_seq_t max) |
391 | $int = $seq->set_range (db_seq_t min, db_seq_t max) |
370 | |
392 | |
371 | Example: |
393 | Example: |
372 | my $seq = $db->sequence; |
394 | my $seq = $db->sequence; |
373 | |
395 | |
374 | db_sequence_open $seq, undef, "seq", BDB::CREATE; |
396 | db_sequence_open $seq, undef, "seq", BDB::CREATE; |
375 | db_sequence_get $seq, undef, 1, my $value; |
397 | db_sequence_get $seq, undef, 1, my $value; |
376 | |
398 | |
377 | SUPPORT FUNCTIONS |
399 | SUPPORT FUNCTIONS |
378 | EVENT PROCESSING AND EVENT LOOP INTEGRATION |
400 | EVENT PROCESSING AND EVENT LOOP INTEGRATION |
379 | $msg = BDB::strerror [$errno] |
401 | $msg = BDB::strerror [$errno] |
380 | Returns the string corresponding to the given errno value. If no |
402 | Returns the string corresponding to the given errno value. If no |
381 | argument is given, use $!. |
403 | argument is given, use $!. |
382 | |
404 | |
383 | Note that the BDB module also patches the $! variable directly, so |
405 | Note that the BDB module also patches the $! variable directly, so |
… | |
… | |
460 | Strictly equivalent to: |
482 | Strictly equivalent to: |
461 | |
483 | |
462 | BDB::poll_wait, BDB::poll_cb |
484 | BDB::poll_wait, BDB::poll_cb |
463 | while BDB::nreqs; |
485 | while BDB::nreqs; |
464 | |
486 | |
|
|
487 | VERSION CHECKING |
|
|
488 | BerkeleyDB comes in various versions, many of them have minor |
|
|
489 | incompatibilities. This means that traditional "at least version x.x" |
|
|
490 | checks are often not sufficient. |
|
|
491 | |
|
|
492 | Example: set the log_autoremove option in a way compatible with <v4.7 |
|
|
493 | and v4.7. Note the use of & on the constants to avoid triggering a |
|
|
494 | compiletime bug when the symbol isn't available. |
|
|
495 | |
|
|
496 | $DB_ENV->set_flags (&BDB::LOG_AUTOREMOVE ) if BDB::VERSION v0, v4.7; |
|
|
497 | $DB_ENV->log_set_config (&BDB::LOG_AUTO_REMOVE) if BDB::VERSION v4.7; |
|
|
498 | |
|
|
499 | BDB::VERSION |
|
|
500 | The "BDB::VERSION" function, when called without arguments, returns |
|
|
501 | the Berkeley DB version as a v-string (usually with 3 components). |
|
|
502 | You should use "lt" and "ge" operators exclusively to make |
|
|
503 | comparisons. |
|
|
504 | |
|
|
505 | Example: check for at least version 4.7. |
|
|
506 | |
|
|
507 | BDB::VERSION ge v4.7 or die; |
|
|
508 | |
|
|
509 | BDB::VERSION min-version |
|
|
510 | Returns true if the BDB version is at least the given version |
|
|
511 | (specified as a v-string), false otherwise. |
|
|
512 | |
|
|
513 | Example: check for at least version 4.5. |
|
|
514 | |
|
|
515 | BDB::VERSION v4.7 or die; |
|
|
516 | |
|
|
517 | BDB::VERSION min-version, max-version |
|
|
518 | Returns true of the BDB version is at least version "min-version" |
|
|
519 | (specify "undef" or "v0" for any minimum version) and less then |
|
|
520 | "max-version". |
|
|
521 | |
|
|
522 | Example: check wether version is strictly less then v4.7. |
|
|
523 | |
|
|
524 | BDB::VERSION v0, v4.7 |
|
|
525 | or die "version 4.7 is not yet supported"; |
|
|
526 | |
465 | CONTROLLING THE NUMBER OF THREADS |
527 | CONTROLLING THE NUMBER OF THREADS |
466 | BDB::min_parallel $nthreads |
528 | BDB::min_parallel $nthreads |
467 | Set the minimum number of BDB threads to $nthreads. The current |
529 | Set the minimum number of BDB threads to $nthreads. The current |
468 | default is 8, which means eight asynchronous operations can execute |
530 | default is 8, which means eight asynchronous operations can execute |
469 | concurrently at any one time (the number of outstanding requests, |
531 | concurrently at any one time (the number of outstanding requests, |
470 | however, is unlimited). |
532 | however, is unlimited). |
… | |
… | |
529 | You can still queue as many requests as you want. Therefore, |
591 | You can still queue as many requests as you want. Therefore, |
530 | "max_oustsanding" is mainly useful in simple scripts (with low |
592 | "max_oustsanding" is mainly useful in simple scripts (with low |
531 | values) or as a stop gap to shield against fatal memory overflow |
593 | values) or as a stop gap to shield against fatal memory overflow |
532 | (with large values). |
594 | (with large values). |
533 | |
595 | |
534 | BDB::set_sync_prepare $cb |
596 | $old_cb = BDB::set_sync_prepare $cb |
535 | Sets a callback that is called whenever a request is created without |
597 | Sets a callback that is called whenever a request is created without |
536 | an explicit callback. It has to return two code references. The |
598 | an explicit callback. It has to return two code references. The |
537 | first is used as the request callback, and the second is called to |
599 | first is used as the request callback (it should save the return |
538 | wait until the first callback has been called. The default |
600 | status), and the second is called to wait until the first callback |
539 | implementation works like this: |
601 | has been called (it must set $! to the return status). |
|
|
602 | |
|
|
603 | This mechanism can be used to include BDB into other event |
|
|
604 | mechanisms, such as Coro::BDB. |
|
|
605 | |
|
|
606 | To allow other, callback-based, events to be executed while |
|
|
607 | callback-less ones are run, you could use this sync prepare |
|
|
608 | function: |
540 | |
609 | |
541 | sub { |
610 | sub { |
542 | my $status; |
611 | my $status; |
543 | ( |
612 | ( |
544 | sub { $status = $! }, |
613 | sub { $status = $! }, |
545 | sub { BDB::poll while !defined $status; $! = $status }, |
614 | sub { BDB::poll while !defined $status; $! = $status }, |
546 | ) |
615 | ) |
547 | } |
616 | } |
548 | |
617 | |
|
|
618 | It works by polling for results till the request has finished and |
|
|
619 | then sets $! to the return value. This means that if you don't use a |
|
|
620 | callback, BDB would simply fall back to synchronous operations. |
|
|
621 | |
|
|
622 | By default, or if the sync prepare function is set to "undef", is to |
|
|
623 | execute callback-less BDB requests in the foreground thread, setting |
|
|
624 | $! to the return value, without polling for other events. |
|
|
625 | |
549 | STATISTICAL INFORMATION |
626 | STATISTICAL INFORMATION |
550 | BDB::nreqs |
627 | BDB::nreqs |
551 | Returns the number of requests currently in the ready, execute or |
628 | Returns the number of requests currently in the ready, execute or |
552 | pending states (i.e. for which their callback has not been invoked |
629 | pending states (i.e. for which their callback has not been invoked |
553 | yet). |
630 | yet). |
554 | |
631 | |
… | |
… | |
563 | |
640 | |
564 | BDB::npending |
641 | BDB::npending |
565 | Returns the number of requests currently in the pending state |
642 | Returns the number of requests currently in the pending state |
566 | (executed, but not yet processed by poll_cb). |
643 | (executed, but not yet processed by poll_cb). |
567 | |
644 | |
|
|
645 | COMMON PITFALLS |
|
|
646 | Unexpected Crashes |
|
|
647 | Remember that, by default, BDB will execute requests in parallel, in |
|
|
648 | somewhat random order. That means that it is easy to run a "db_get" |
|
|
649 | request on the same database as a concurrent "db_close" request, leading |
|
|
650 | to a crash, silent data corruption, eventually the next world war on |
|
|
651 | terrorism. |
|
|
652 | |
|
|
653 | If you only ever use foreground requests (without a callback), this will |
|
|
654 | not be an issue (unless you use threads). |
|
|
655 | |
|
|
656 | Unexpected Freezes or Deadlocks |
|
|
657 | Remember that, by default, BDB will execute requests in parallel, which |
|
|
658 | easily leads to deadlocks (even concurrent put's on the same database |
|
|
659 | can deadlock). |
|
|
660 | |
|
|
661 | You either need to run deadlock detection (and handle the resulting |
|
|
662 | errors), or make sure only one process ever updates the database, ine |
|
|
663 | one thread, e.g. by using only foreground requests (without a callback). |
|
|
664 | |
568 | FORK BEHAVIOUR |
665 | FORK BEHAVIOUR |
569 | This module should do "the right thing" when the process using it forks: |
666 | This module should do "the right thing" when the process using it forks: |
570 | |
667 | |
571 | Before the fork, BDB enters a quiescent state where no requests can be |
668 | Before the fork, BDB enters a quiescent state where no requests can be |
572 | added in other threads and no results will be processed. After the fork |
669 | added in other threads and no results will be processed. After the fork |
573 | the parent simply leaves the quiescent state and continues |
670 | the parent simply leaves the quiescent state and continues |
… | |
… | |
582 | |
679 | |
583 | Win32 note: there is no fork on win32, and perls emulation of it is too |
680 | Win32 note: there is no fork on win32, and perls emulation of it is too |
584 | broken to be supported, so do not use BDB in a windows pseudo-fork, |
681 | broken to be supported, so do not use BDB in a windows pseudo-fork, |
585 | better yet, switch to a more capable platform. |
682 | better yet, switch to a more capable platform. |
586 | |
683 | |
587 | MEMORY USAGE |
684 | MEMORY USAGE |
588 | Per-request usage: |
685 | Per-request usage: |
589 | |
686 | |
590 | Each aio request uses - depending on your architecture - around 100-200 |
687 | Each aio request uses - depending on your architecture - around 100-200 |
591 | bytes of memory. In addition, stat requests need a stat buffer (possibly |
688 | bytes of memory. In addition, stat requests need a stat buffer (possibly |
592 | a few hundred bytes), readdir requires a result buffer and so on. Perl |
689 | a few hundred bytes), readdir requires a result buffer and so on. Perl |
… | |
… | |
600 | |
697 | |
601 | In the execution phase, some aio requests require more memory for |
698 | In the execution phase, some aio requests require more memory for |
602 | temporary buffers, and each thread requires a stack and other data |
699 | temporary buffers, and each thread requires a stack and other data |
603 | structures (usually around 16k-128k, depending on the OS). |
700 | structures (usually around 16k-128k, depending on the OS). |
604 | |
701 | |
|
|
702 | WIN32 FILENAMES/DATABASE NAME MESS |
|
|
703 | Perl on Win32 supports only ASCII filenames (the reason is that it |
|
|
704 | abuses an internal flag to store wether a filename is Unicode or ANSI, |
|
|
705 | but that flag is used for somethign else in the perl core, so there is |
|
|
706 | no way to detect wether a filename is ANSI or Unicode-encoded). The BDB |
|
|
707 | module tries to work around this issue by assuming that the filename is |
|
|
708 | an ANSI filename and BDB was built for unicode support. |
|
|
709 | |
605 | KNOWN BUGS |
710 | KNOWN BUGS |
606 | Known bugs will be fixed in the next release, except: |
711 | Known bugs will be fixed in the next release, except: |
607 | |
712 | |
608 | If you use a transaction in any request, and the request returns |
713 | If you use a transaction in any request, and the request returns |
609 | with an operating system error or DB_LOCK_NOTGRANTED, the internal |
714 | with an operating system error or DB_LOCK_NOTGRANTED, the internal |