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

Comparing BDB/BDB.pm (file contents):
Revision 1.6 by root, Sun Feb 11 22:07:23 2007 UTC vs.
Revision 1.18 by root, Tue Dec 4 11:07:39 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 = '1.2';
69		78
70	our @BDB_REQ = qw(	79	our @BDB_REQ = qw(
71	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
72	db_env_memp_sync db_env_memp_trickle	81	db_env_memp_sync db_env_memp_trickle
73	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
74	db_txn_commit db_txn_abort	83	db_txn_commit db_txn_abort db_txn_finish
75	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
76	db_sequence_open db_sequence_close	85	db_sequence_open db_sequence_close
77	db_sequence_get db_sequence_remove	86	db_sequence_get db_sequence_remove
78	);	87	);
79	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));
…		…
86		95
87	require XSLoader;	96	require XSLoader;
88	XSLoader::load ("BDB", $VERSION);	97	XSLoader::load ("BDB", $VERSION);
89	}	98	}
90		99
		100	=head2 BERKELEYDB FUNCTIONS
		101
		102	All of these are functions. The create functions simply return a new
		103	object and never block. All the remaining functions all take an optional
		104	callback as last argument. If it is missing, then the fucntion will be
		105	executed synchronously.
		106
		107	BDB functions that cannot block (mostly functions that manipulate
		108	settings) are method calls on the relevant objects, so the rule of thumb
		109	is: if its a method, its not blocking, if its a function, it takes a
		110	callback as last argument.
		111
		112	In the following, C<$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
		386
91	=head2 SUPPORT FUNCTIONS	387	=head2 SUPPORT FUNCTIONS
92		388
93	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION	389	=head3 EVENT PROCESSING AND EVENT LOOP INTEGRATION
94		390
95	=over 4	391	=over 4
…		…
139	interactiveness when perl is not fast enough to process all requests in	435	interactiveness when perl is not fast enough to process all requests in
140	time.	436	time.
141		437
142	For interactive programs, values such as C<0.01> to C<0.1> should be fine.	438	For interactive programs, values such as C<0.01> to C<0.1> should be fine.
143		439
144	Example: Install an Event watcher that automatically calls	440	Example: Install an EV watcher that automatically calls
145	BDB::poll_cb with low priority, to ensure that other parts of the	441	BDB::poll_cb with low priority, to ensure that other parts of the
146	program get the CPU sometimes even under high AIO load.	442	program get the CPU sometimes even under high load.
147		443
148	# try not to spend much more than 0.1s in poll_cb	444	# try not to spend much more than 0.1s in poll_cb
149	BDB::max_poll_time 0.1;	445	BDB::max_poll_time 0.1;
150		446
151	# use a low priority so other tasks have priority	447	my $bdb_poll = EV::io BDB::poll_fileno, EV::READ, \&BDB::poll_cb);
152	Event->io (fd => BDB::poll_fileno,
153	poll => 'r', nice => 1,
154	cb => &BDB::poll_cb);
155		448
156	=item BDB::poll_wait	449	=item BDB::poll_wait
157		450
158	If there are any outstanding requests and none of them in the result	451	If there are any outstanding requests and none of them in the result
159	phase, wait till the result filehandle becomes ready for reading (simply	452	phase, wait till the result filehandle becomes ready for reading (simply
…		…
171		464
172	BDB::poll_wait, BDB::poll_cb	465	BDB::poll_wait, BDB::poll_cb
173		466
174	=item BDB::flush	467	=item BDB::flush
175		468
176	Wait till all outstanding AIO requests have been handled.	469	Wait till all outstanding BDB requests have been handled.
177		470
178	Strictly equivalent to:	471	Strictly equivalent to:
179		472
180	BDB::poll_wait, BDB::poll_cb	473	BDB::poll_wait, BDB::poll_cb
181	while BDB::nreqs;	474	while BDB::nreqs;
182		475
		476	=back
		477
183	=head3 CONTROLLING THE NUMBER OF THREADS	478	=head3 CONTROLLING THE NUMBER OF THREADS
184		479
		480	=over 4
		481
185	=item BDB::min_parallel $nthreads	482	=item BDB::min_parallel $nthreads
186		483
187	Set the minimum number of AIO threads to C<$nthreads>. The current	484	Set the minimum number of BDB threads to C<$nthreads>. The current
188	default is C<8>, which means eight asynchronous operations can execute	485	default is C<8>, which means eight asynchronous operations can execute
189	concurrently at any one time (the number of outstanding requests,	486	concurrently at any one time (the number of outstanding requests,
190	however, is unlimited).	487	however, is unlimited).
191		488
192	BDB starts threads only on demand, when an AIO request is queued and	489	BDB starts threads only on demand, when an BDB request is queued and
193	no free thread exists. Please note that queueing up a hundred requests can	490	no free thread exists. Please note that queueing up a hundred requests can
194	create demand for a hundred threads, even if it turns out that everything	491	create demand for a hundred threads, even if it turns out that everything
195	is in the cache and could have been processed faster by a single thread.	492	is in the cache and could have been processed faster by a single thread.
196		493
197	It is recommended to keep the number of threads relatively low, as some	494	It is recommended to keep the number of threads relatively low, as some
…		…
202	Under most circumstances you don't need to call this function, as the	499	Under most circumstances you don't need to call this function, as the
203	module selects a default that is suitable for low to moderate load.	500	module selects a default that is suitable for low to moderate load.
204		501
205	=item BDB::max_parallel $nthreads	502	=item BDB::max_parallel $nthreads
206		503
207	Sets the maximum number of AIO threads to C<$nthreads>. If more than the	504	Sets the maximum number of BDB threads to C<$nthreads>. If more than the
208	specified number of threads are currently running, this function kills	505	specified number of threads are currently running, this function kills
209	them. This function blocks until the limit is reached.	506	them. This function blocks until the limit is reached.
210		507
211	While C<$nthreads> are zero, aio requests get queued but not executed	508	While C<$nthreads> are zero, aio requests get queued but not executed
212	until the number of threads has been increased again.	509	until the number of threads has been increased again.
…		…
315		612
316	=head2 FORK BEHAVIOUR	613	=head2 FORK BEHAVIOUR
317		614
318	This module should do "the right thing" when the process using it forks:	615	This module should do "the right thing" when the process using it forks:
319		616
320	Before the fork, IO::AIO enters a quiescent state where no requests	617	Before the fork, BDB enters a quiescent state where no requests
321	can be added in other threads and no results will be processed. After	618	can be added in other threads and no results will be processed. After
322	the fork the parent simply leaves the quiescent state and continues	619	the fork the parent simply leaves the quiescent state and continues
323	request/result processing, while the child frees the request/result queue	620	request/result processing, while the child frees the request/result queue
324	(so that the requests started before the fork will only be handled in the	621	(so that the requests started before the fork will only be handled in the
325	parent). Threads will be started on demand until the limit set in the	622	parent). Threads will be started on demand until the limit set in the
326	parent process has been reached again.	623	parent process has been reached again.
327		624
328	In short: the parent will, after a short pause, continue as if fork had	625	In short: the parent will, after a short pause, continue as if fork had
329	not been called, while the child will act as if IO::AIO has not been used	626	not been called, while the child will act as if BDB has not been used
330	yet.	627	yet.
331		628
332	=head2 MEMORY USAGE	629	=head2 MEMORY USAGE
333		630
334	Per-request usage:	631	Per-request usage:
…		…
337	bytes of memory. In addition, stat requests need a stat buffer (possibly	634	bytes of memory. In addition, stat requests need a stat buffer (possibly
338	a few hundred bytes), readdir requires a result buffer and so on. Perl	635	a few hundred bytes), readdir requires a result buffer and so on. Perl
339	scalars and other data passed into aio requests will also be locked and	636	scalars and other data passed into aio requests will also be locked and
340	will consume memory till the request has entered the done state.	637	will consume memory till the request has entered the done state.
341		638
342	This is now awfully much, so queuing lots of requests is not usually a	639	This is not awfully much, so queuing lots of requests is not usually a
343	problem.	640	problem.
344		641
345	Per-thread usage:	642	Per-thread usage:
346		643
347	In the execution phase, some aio requests require more memory for	644	In the execution phase, some aio requests require more memory for
348	temporary buffers, and each thread requires a stack and other data	645	temporary buffers, and each thread requires a stack and other data
349	structures (usually around 16k-128k, depending on the OS).	646	structures (usually around 16k-128k, depending on the OS).
350		647
351	=head1 KNOWN BUGS	648	=head1 KNOWN BUGS
352		649
353	Known bugs will be fixed in the next release.	650	Known bugs will be fixed in the next release, except:
		651
		652	If you use a transaction in any request, and the request returns
		653	with an operating system error or DB_LOCK_NOTGRANTED, the internal
		654	TXN_DEADLOCK flag will be set on the transaction. See C<db_txn_finish>,
		655	above.
354		656
355	=head1 SEE ALSO	657	=head1 SEE ALSO
356		658
357	L<Coro::AIO>.	659	L<Coro::BDB>, L<IO::AIO>.
358		660
359	=head1 AUTHOR	661	=head1 AUTHOR
360		662
361	Marc Lehmann <schmorp@schmorp.de>	663	Marc Lehmann <schmorp@schmorp.de>
362	http://home.schmorp.de/	664	http://home.schmorp.de/

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Comparing BDB/BDB.pm (file contents): Revision 1.6 by root, Sun Feb 11 22:07:23 2007 UTC vs. Revision 1.18 by root, Tue Dec 4 11:07:39 2007 UTC

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Comparing BDB/BDB.pm (file contents):
Revision 1.6 by root, Sun Feb 11 22:07:23 2007 UTC vs.
Revision 1.18 by root, Tue Dec 4 11:07:39 2007 UTC