[ViewVC] Diff of: cvs/BDB/BDB.pm

Comparing BDB/BDB.pm (file contents):
Revision 1.4 by root, Mon Feb 5 23:46:15 2007 UTC vs.
Revision 1.16 by root, Sun Sep 16 18:17:58 2007 UTC

…		…
6		6
7	use BDB;	7	use BDB;
8		8
9	=head1 DESCRIPTION	9	=head1 DESCRIPTION
10		10
11	=head2 EXAMPLE	11	See the BerkeleyDB documentation (L<http://www.oracle.com/technology/documentation/berkeley-db/db/index.html>).
		12	The BDB API is very similar to the C API (the translation has been very faithful).
		13
		14	See also the example sections in the document below and possibly the eg/
		15	subdirectory of the BDB distribution. Last not least see the IO::AIO
		16	documentation, as that module uses almost the same asynchronous request
		17	model as this module.
		18
		19	I know this is woefully inadequate documentation. Send a patch!
		20
12		21
13	=head1 REQUEST ANATOMY AND LIFETIME	22	=head1 REQUEST ANATOMY AND LIFETIME
14		23
15	Every request method creates a request. which is a C data structure not	24	Every request method creates a request. which is a C data structure not
16	directly visible to Perl.	25	directly visible to Perl.
…		…
63	use strict 'vars';	72	use strict 'vars';
64		73
65	use base 'Exporter';	74	use base 'Exporter';
66		75
67	BEGIN {	76	BEGIN {
68	our $VERSION = '0.1';	77	our $VERSION = '1.1';
69		78
70	our @BDB_REQ = qw(	79	our @BDB_REQ = qw(
71	db_env_create db_env_open db_env_close	80	db_env_open db_env_close db_env_txn_checkpoint db_env_lock_detect
		81	db_env_memp_sync db_env_memp_trickle
72	db_create db_open db_close db_compact db_sync db_put db_get db_pget	82	db_open db_close db_compact db_sync db_put db_get db_pget db_del db_key_range
73	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
		85	db_sequence_open db_sequence_close
		86	db_sequence_get db_sequence_remove
74	);	87	);
75	our @EXPORT = (@BDB_REQ, qw(dbreq_pri dbreq_nice));	88	our @EXPORT = (@BDB_REQ, qw(dbreq_pri dbreq_nice db_env_create db_create));
		89	our @EXPORT_OK = qw(
76	our @EXPORT_OK = qw(poll_fileno poll_cb poll_wait flush	90	poll_fileno poll_cb poll_wait flush
77	min_parallel max_parallel max_idle	91	min_parallel max_parallel max_idle
78	nreqs nready npending nthreads	92	nreqs nready npending nthreads
79	max_poll_time max_poll_reqs);	93	max_poll_time max_poll_reqs
		94	);
80		95
81	require XSLoader;	96	require XSLoader;
82	XSLoader::load ("BDB", $VERSION);	97	XSLoader::load ("BDB", $VERSION);
83	}	98	}
		99
		100	=head2 BERKELEYDB FUNCTIONS
		101
		102	All of these are functions. The create functions simply return a new
		103	object and never block. All the remaining functions all take an optional
		104	callback as last argument. If it is missing, then the fucntion will be
		105	executed synchronously.
		106
		107	BDB functions that cannot block (mostly functions that manipulate
		108	settings) are method calls on the relevant objects, so the rule of thumb
		109	is: if its a method, its not blocking, if its a function, it takes a
		110	callback as last argument.
		111
		112	In the following, C<$int> signifies an integer return value,
		113	C<octetstring> is a "binary string" (i.e. a perl string with no character
		114	indices >255), C<U32> is an unsigned 32 bit integer, C<int> is some
		115	integer, C<NV> is a floating point value.
		116
		117	The C<SV *> types are generic perl scalars (for input and output of data
		118	values), and the C<SV *callback> is the optional callback function to call
		119	when the request is completed.
		120
		121	The various C<DB_ENV> etc. arguments are handles return by
		122	C<db_env_create>, C<db_create>, C<txn_begin> and so on. If they have an
		123	appended C<_ornull> this means they are optional and you can pass C<undef>
		124	for them, resulting a NULL pointer on the C level.
		125
		126	=head3 BDB functions
		127
		128	Functions in the BDB namespace, exported by default:
		129
		130	$env = db_env_create (U32 env_flags = 0)
		131	flags: RPCCLIENT
		132
		133	db_env_open (DB_ENV env, octetstring db_home, U32 open_flags, int mode, SV callback = &PL_sv_undef)
		134	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
		135	db_env_close (DB_ENV env, U32 flags = 0, SV callback = &PL_sv_undef)
		136	db_env_txn_checkpoint (DB_ENV env, U32 kbyte = 0, U32 min = 0, U32 flags = 0, SV callback = &PL_sv_undef)
		137	flags: FORCE
		138	db_env_lock_detect (DB_ENV env, U32 flags = 0, U32 atype = DB_LOCK_DEFAULT, SV dummy = 0, SV *callback = &PL_sv_undef)
		139	atype: LOCK_DEFAULT LOCK_EXPIRE LOCK_MAXLOCKS LOCK_MAXWRITE LOCK_MINLOCKS LOCK_MINWRITE LOCK_OLDEST LOCK_RANDOM LOCK_YOUNGEST
		140	db_env_memp_sync (DB_ENV env, SV dummy = 0, SV *callback = &PL_sv_undef)
		141	db_env_memp_trickle (DB_ENV env, int percent, SV dummy = 0, SV *callback = &PL_sv_undef)
		142
		143	$db = db_create (DB_ENV *env = 0, U32 flags = 0)
		144	flags: XA_CREATE
		145
		146	db_open (DB db, DB_TXN_ornull txnid, octetstring file, octetstring database, int type, U32 flags, int mode, SV *callback = &PL_sv_undef)
		147	flags: AUTO_COMMIT CREATE EXCL MULTIVERSION NOMMAP RDONLY READ_UNCOMMITTED THREAD TRUNCATE
		148	db_close (DB db, U32 flags = 0, SV callback = &PL_sv_undef)
		149	flags: DB_NOSYNC
		150	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)
		151	flags: FREELIST_ONLY FREE_SPACE
		152	db_sync (DB db, U32 flags = 0, SV callback = &PL_sv_undef)
		153	db_key_range (DB db, DB_TXN_ornull txn, SV key, SV key_range, U32 flags = 0, SV *callback = &PL_sv_undef)
		154	db_put (DB db, DB_TXN_ornull txn, SV key, SV data, U32 flags = 0, SV *callback = &PL_sv_undef)
		155	flags: APPEND NODUPDATA NOOVERWRITE
		156	db_get (DB db, DB_TXN_ornull txn, SV key, SV data, U32 flags = 0, SV *callback = &PL_sv_undef)
		157	flags: CONSUME CONSUME_WAIT GET_BOTH SET_RECNO MULTIPLE READ_COMMITTED READ_UNCOMMITTED RMW
		158	db_pget (DB db, DB_TXN_ornull txn, SV key, SV pkey, SV data, U32 flags = 0, SV callback = &PL_sv_undef)
		159	flags: CONSUME CONSUME_WAIT GET_BOTH SET_RECNO MULTIPLE READ_COMMITTED READ_UNCOMMITTED RMW
		160	db_del (DB db, DB_TXN_ornull txn, SV key, U32 flags = 0, SV callback = &PL_sv_undef)
		161	db_txn_commit (DB_TXN txn, U32 flags = 0, SV callback = &PL_sv_undef)
		162	flags: TXN_NOSYNC TXN_SYNC
		163	db_txn_abort (DB_TXN txn, SV callback = &PL_sv_undef)
		164
		165	db_c_close (DBC dbc, SV callback = &PL_sv_undef)
		166	db_c_count (DBC dbc, SV count, U32 flags = 0, SV *callback = &PL_sv_undef)
		167	db_c_put (DBC dbc, SV key, SV data, U32 flags = 0, SV callback = &PL_sv_undef)
		168	flags: AFTER BEFORE CURRENT KEYFIRST KEYLAST NODUPDATA
		169	db_c_get (DBC dbc, SV key, SV data, U32 flags = 0, SV callback = &PL_sv_undef)
		170	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
		171	db_c_pget (DBC dbc, SV key, SV pkey, SV data, U32 flags = 0, SV *callback = &PL_sv_undef)
		172	db_c_del (DBC dbc, U32 flags = 0, SV callback = &PL_sv_undef)
		173
		174	db_sequence_open (DB_SEQUENCE seq, DB_TXN_ornull txnid, SV key, U32 flags = 0, SV callback = &PL_sv_undef)
		175	flags: CREATE EXCL
		176	db_sequence_close (DB_SEQUENCE seq, U32 flags = 0, 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
		179	db_sequence_remove (DB_SEQUENCE seq, DB_TXN_ornull txnid = 0, U32 flags = 0, SV *callback = &PL_sv_undef)
		180	flags: TXN_NOSYNC
		181
		182	=head4 db_txn_finish (DB_TXN txn, U32 flags = 0, SV callback = &PL_sv_undef)
		183
		184	This is not actually a Berkeley DB function but a BDB module
		185	extension. The background for this exytension is: It is very annoying to
		186	have to check every single BDB function for error returns and provide a
		187	codepath out of your transaction. While the BDB module still makes this
		188	possible, it contains the following extensions:
		189
		190	When a transaction-protected function returns any operating system
		191	error (errno > 0), BDB will set the C<TXN_DEADLOCK> flag on the
		192	transaction. This flag is also set by Berkeley DB functions themselves
		193	when an operation fails with LOCK_DEADLOCK, and it causes all further
		194	operations on that transaction (including C<db_txn_commit>) to fail.
		195
		196	The C<db_txn_finish> request will look at this flag, and, if it is set,
		197	will automatically call C<db_txn_abort> (setting errno to C<LOCK_DEADLOCK>
		198	if it isn't set to something else yet). If it isn't set, it will call
		199	C<db_txn_commit> and return the error normally.
		200
		201	How 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
		209	That 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
		211	requests (db_put in this case) will simply be skipped (they will fail with
		212	LOCK_DEADLOCK) and the transaction will be aborted.
		213
		214	You can use the C<< $txn->failed >> method to check wether a transaction
		215	has failed in this way and abort further processing (excluding
		216	C<db_txn_finish>).
		217
		218	=head3 DB_ENV/database environment methods
		219
		220	Methods available on DB_ENV/$env handles:
		221
		222	DESTROY (DB_ENV_ornull *env)
		223	CODE:
		224	if (env)
		225	env->close (env, 0);
		226
		227	$int = $env->set_data_dir (const char *dir)
		228	$int = $env->set_tmp_dir (const char *dir)
		229	$int = $env->set_lg_dir (const char *dir)
		230	$int = $env->set_shm_key (long shm_key)
		231	$int = $env->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0)
		232	$int = $env->set_flags (U32 flags, int onoff)
		233	$env->set_errfile (FILE *errfile = 0)
		234	$env->set_msgfile (FILE *msgfile = 0)
		235	$int = $env->set_verbose (U32 which, int onoff = 1)
		236	$int = $env->set_encrypt (const char *password, U32 flags = 0)
		237	$int = $env->set_timeout (NV timeout_seconds, U32 flags = SET_TXN_TIMEOUT)
		238	$int = $env->set_mp_max_openfd (int maxopenfd);
		239	$int = $env->set_mp_max_write (int maxwrite, int maxwrite_sleep);
		240	$int = $env->set_mp_mmapsize (int mmapsize_mb)
		241	$int = $env->set_lk_detect (U32 detect = DB_LOCK_DEFAULT)
		242	$int = $env->set_lk_max_lockers (U32 max)
		243	$int = $env->set_lk_max_locks (U32 max)
		244	$int = $env->set_lk_max_objects (U32 max)
		245	$int = $env->set_lg_bsize (U32 max)
		246	$int = $env->set_lg_max (U32 max)
		247
		248	$txn = $env->txn_begin (DB_TXN_ornull *parent = 0, U32 flags = 0)
		249	flags: READ_COMMITTED READ_UNCOMMITTED TXN_NOSYNC TXN_NOWAIT TXN_SNAPSHOT TXN_SYNC TXN_WAIT TXN_WRITE_NOSYNC
		250
		251	=head4 Example:
		252
		253	use AnyEvent;
		254	use BDB;
		255
		256	our $FH; open $FH, "<&=" . BDB::poll_fileno;
		257	our $WATCHER = AnyEvent->io (fh => $FH, poll => 'r', cb => \&BDB::poll_cb);
		258
		259	BDB::min_parallel 8;
		260
		261	my $env = db_env_create;
		262
		263	mkdir "bdtest", 0700;
		264	db_env_open
		265	$env,
		266	"bdtest",
		267	BDB::INIT_LOCK \| BDB::INIT_LOG \| BDB::INIT_MPOOL \| BDB::INIT_TXN \| BDB::RECOVER \| BDB::USE_ENVIRON \| BDB::CREATE,
		268	0600;
		269
		270	$env->set_flags (BDB::AUTO_COMMIT \| BDB::TXN_NOSYNC, 1);
		271
		272
		273	=head3 DB/database methods
		274
		275	Methods available on DB/$db handles:
		276
		277	DESTROY (DB_ornull *db)
		278	CODE:
		279	if (db)
		280	{
		281	SV env = (SV )db->app_private;
		282	db->close (db, 0);
		283	SvREFCNT_dec (env);
		284	}
		285
		286	$int = $db->set_cachesize (U32 gbytes, U32 bytes, int ncache = 0)
		287	$int = $db->set_flags (U32 flags)
		288	flags: CHKSUM ENCRYPT TXN_NOT_DURABLE
		289	Btree: DUP DUPSORT RECNUM REVSPLITOFF
		290	Hash: DUP DUPSORT
		291	Queue: INORDER
		292	Recno: RENUMBER SNAPSHOT
		293
		294	$int = $db->set_encrypt (const char *password, U32 flags)
		295	$int = $db->set_lorder (int lorder)
		296	$int = $db->set_bt_minkey (U32 minkey)
		297	$int = $db->set_re_delim (int delim)
		298	$int = $db->set_re_pad (int re_pad)
		299	$int = $db->set_re_source (char *source)
		300	$int = $db->set_re_len (U32 re_len)
		301	$int = $db->set_h_ffactor (U32 h_ffactor)
		302	$int = $db->set_h_nelem (U32 h_nelem)
		303	$int = $db->set_q_extentsize (U32 extentsize)
		304
		305	$dbc = $db->cursor (DB_TXN_ornull *txn = 0, U32 flags = 0)
		306	flags: READ_COMMITTED READ_UNCOMMITTED WRITECURSOR TXN_SNAPSHOT
		307	$seq = $db->sequence (U32 flags = 0)
		308
		309	=head4 Example:
		310
		311	my $db = db_create $env;
		312	db_open $db, undef, "table", undef, BDB::BTREE, BDB::AUTO_COMMIT \| BDB::CREATE \| BDB::READ_UNCOMMITTED, 0600;
		313
		314	for (1..1000) {
		315	db_put $db, undef, "key $_", "data $_";
		316
		317	db_key_range $db, undef, "key $_", my $keyrange;
		318	my ($lt, $eq, $gt) = @$keyrange;
		319	}
		320
		321	db_del $db, undef, "key $_" for 1..1000;
		322
		323	db_sync $db;
		324
		325
		326	=head3 DB_TXN/transaction methods
		327
		328	Methods available on DB_TXN/$txn handles:
		329
		330	DESTROY (DB_TXN_ornull *txn)
		331	CODE:
		332	if (txn)
		333	txn->abort (txn);
		334
		335	$int = $txn->set_timeout (NV timeout_seconds, U32 flags = SET_TXN_TIMEOUT)
		336	flags: SET_LOCK_TIMEOUT SET_TXN_TIMEOUT
		337
		338	$bool = $txn->failed
		339	# see db_txn_finish documentation, above
		340
		341
		342	=head3 DBC/cursor methods
		343
		344	Methods available on DBC/$dbc handles:
		345
		346	DESTROY (DBC_ornull *dbc)
		347	CODE:
		348	if (dbc)
		349	dbc->c_close (dbc);
		350
		351	=head4 Example:
		352
		353	my $c = $db->cursor;
		354
		355	for (;;) {
		356	db_c_get $c, my $key, my $data, BDB::NEXT;
		357	warn "<$!,$key,$data>";
		358	last if $!;
		359	}
		360
		361	db_c_close $c;
		362
		363
		364	=head3 DB_SEQUENCE/sequence methods
		365
		366	Methods available on DB_SEQUENCE/$seq handles:
		367
		368	DESTROY (DB_SEQUENCE_ornull *seq)
		369	CODE:
		370	if (seq)
		371	seq->close (seq, 0);
		372
		373	$int = $seq->initial_value (db_seq_t value)
		374	$int = $seq->set_cachesize (U32 size)
		375	$int = $seq->set_flags (U32 flags)
		376	flags: SEQ_DEC SEQ_INC SEQ_WRAP
		377	$int = $seq->set_range (db_seq_t min, db_seq_t max)
		378
		379	=head4 Example:
		380
		381	my $seq = $db->sequence;
		382
		383	db_sequence_open $seq, undef, "seq", BDB::CREATE;
		384	db_sequence_get $seq, undef, 1, my $value;
		385
84		386
85	=head2 SUPPORT FUNCTIONS	387	=head2 SUPPORT FUNCTIONS
86		388
87	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	389	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
88		390
…		…
172	Strictly equivalent to:	474	Strictly equivalent to:
173		475
174	BDB::poll_wait, BDB::poll_cb	476	BDB::poll_wait, BDB::poll_cb
175	while BDB::nreqs;	477	while BDB::nreqs;
176		478
		479	=back
		480
177	=head3 CONTROLLING THE NUMBER OF THREADS	481	=head3 CONTROLLING THE NUMBER OF THREADS
		482
		483	=over 4
178		484
179	=item BDB::min_parallel $nthreads	485	=item BDB::min_parallel $nthreads
180		486
181	Set the minimum number of AIO threads to C<$nthreads>. The current	487	Set the minimum number of AIO threads to C<$nthreads>. The current
182	default is C<8>, which means eight asynchronous operations can execute	488	default is C<8>, which means eight asynchronous operations can execute
…		…
331	bytes of memory. In addition, stat requests need a stat buffer (possibly	637	bytes of memory. In addition, stat requests need a stat buffer (possibly
332	a few hundred bytes), readdir requires a result buffer and so on. Perl	638	a few hundred bytes), readdir requires a result buffer and so on. Perl
333	scalars and other data passed into aio requests will also be locked and	639	scalars and other data passed into aio requests will also be locked and
334	will consume memory till the request has entered the done state.	640	will consume memory till the request has entered the done state.
335		641
336	This is now awfully much, so queuing lots of requests is not usually a	642	This is not awfully much, so queuing lots of requests is not usually a
337	problem.	643	problem.
338		644
339	Per-thread usage:	645	Per-thread usage:
340		646
341	In the execution phase, some aio requests require more memory for	647	In the execution phase, some aio requests require more memory for
342	temporary buffers, and each thread requires a stack and other data	648	temporary buffers, and each thread requires a stack and other data
343	structures (usually around 16k-128k, depending on the OS).	649	structures (usually around 16k-128k, depending on the OS).
344		650
345	=head1 KNOWN BUGS	651	=head1 KNOWN BUGS
346		652
347	Known bugs will be fixed in the next release.	653	Known 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.
348		659
349	=head1 SEE ALSO	660	=head1 SEE ALSO
350		661
351	L<Coro::AIO>.	662	L<Coro::AIO>.
352		663

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Comparing BDB/BDB.pm (file contents): Revision 1.4 by root, Mon Feb 5 23:46:15 2007 UTC vs. Revision 1.16 by root, Sun Sep 16 18:17:58 2007 UTC

Diff Legend

Comparing BDB/BDB.pm (file contents):
Revision 1.4 by root, Mon Feb 5 23:46:15 2007 UTC vs.
Revision 1.16 by root, Sun Sep 16 18:17:58 2007 UTC