Tuesday, July 31. 2007

PECL/tdb - PHP interface for Trivial DB

Evgeny Stepanischev asked me yesterday why there is no PECL extension providing interface to Trivial DB (TDB), which is used in Samba. I didn't know what to answer, so I... wrote it =)
The TDB itself looks like a perfect solution for temporary data storage (caches, sessions and the like), but it might be also useful for something more complex, taking into account its transactions support.

Being curious of how it would perform comparing to Memcached on localhost (using PECL/memcache, of course) I did a quick benchmark.
It's purely syntetic (just 1 000 000 operations in a loop), but the numbers show clear difference.

These are the results:


Impressive, huh?
Posted by Antony Dovgal in PHP at 17:34 | Comments (17)

Comments
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#1 Fabien (Homepage) on 2007-07-31 19:55 (Reply)
I can be wrong, but TDB seems to don't work over the network which is one of the big advantage of memcached (to build a cluster of memcached). Is it possible to do that with TDB or is it only something like BDB (a file-based database).
#1.1 Antony Dovgal (Homepage) on 2007-07-31 19:59 (Reply)
You are right, it doesn't do network.
#1.1.1 Robin (Homepage) on 2007-07-31 21:19 (Reply)
So you've compared a DBM (like QDBM, DB4, CDB, ...) with Memcached (which uses sockets, even if you run the memcached daemon locally)? If so, I'm not surprised about the performance difference.
If you'd plug TDB into the Memcached daemon (or write a daemon yourself) I expect Memcached to be much faster because that is an in-memory hash table vs the on-disk (?) database of TDB.
I'd like to see how TDB compares to ConstantDB and QDBM. You could probably provide it as an extra dba handler in PHP's DBA module as an alternative to the 11 handlers that are already in there :-)
#1.1.1.1 Evgeny Stepanischev (Homepage) on 2007-08-01 13:49 (Reply)
QDBM is very unstable on real projects. I've tested QDBM in adme.ru project and got project base corruption in 0.5-2 hours.
#2 Silvano (Homepage) on 2007-08-01 06:14 (Reply)
Really impressive, but I also would like know how it goes without taking into consideration the socket s time.
#3 Mauro on 2007-08-03 03:31 (Reply)
I'd like to know how memory TDB compares to APC cache, since that seems a fair comparison. Do you have that number?

Regards,
Mauro.
#3.1 Antony Dovgal (Homepage) on 2007-08-03 11:27 (Reply)
Nope. But you can compare it yourself, the sources are available.

Here are some hints on how to compile TDB itself:
http://news.php.net/php.pecl.dev/4832
#4 Artur on 2007-09-20 18:48 (Reply)
Hi,
sorry - I am just looking for opportunity to ask about: how to compile pecl-memcache with hardened php5 (with suhosin patch). Now on my machine runs OpenBSD 4.0.
When apache starts in log I found:

PHP Warning: PHP Startup: memcache: Unable to initialize module
Module compiled without Hardening-Patch, module API=20050922, debug=0,
thread-safety=0
PHP compiled with Hardening-Patch=1002051106, module API=20050922,
debug=0, thread-safety=0
These options need to match

Please help me if Anybody know how :-)

Regards,
Artur
#4.1 Antony Dovgal (Homepage) on 2007-09-20 18:57 (Reply)
No idea, ask the author of the patch.
#5 Lars Pohlmann (Homepage) on 2007-10-29 15:03 (Reply)
The graph looks impressing. I'm using memcached heavily. I'll try out TDB soon.
#5.1 Antony Dovgal (Homepage) on 2007-10-29 15:09 (Reply)
Don't forget that it's just a hash table kept in memory/file, it doesn't have any network support, so there's no surprise it's faster than memcached.
#6 Lars Pohlmann (Homepage) on 2007-10-29 15:13 (Reply)
Yes, but that is exactly what I'm using memcached for at the moment. So TDB seems to be a real alternative.
#7 Lars Pohlmann (Homepage) on 2007-10-29 15:43 (Reply)
It doesn't compile for me (Debian Etch):

# phpize
Configuring for:
PHP Api Version: 20041225
Zend Module Api No: 20060613
Zend Extension Api No: 220060519

# ./configure

somethings missing, so:
...
# apt-get install tdb-dev

Wähle vormals abgewähltes Paket libtdb1.
(Lese Datenbank ... 32708 Dateien und Verzeichnisse sind derzeit installiert.)
Entpacke libtdb1 (aus .../libtdb1_1.0.6-13_i386.deb) ...
Wähle vormals abgewähltes Paket tdb-dev.
Entpacke tdb-dev (aus .../tdb-dev_1.0.6-13_i386.deb) ...
Richte libtdb1 ein (1.0.6-13) ...

Richte tdb-dev ein (1.0.6-13) ...

...
# ./configure (no problems)

# make
/bin/sh /root/tdb-0.0.1/libtool --mode=compile gcc -I. -I/root/tdb-0.0.1 -DPHP_ATOM_INC -I/root/tdb-0.0.1/include -I/root/tdb-0.0.1/main -I/root/tdb-0.0.1 -I/usr/include/php5 -I/usr/include/php5/main -I/usr/include/php5/TSRM -I/usr/include/php5/Zend -I/usr/include/php5/ext -I/usr/include/php5/ext/date/lib -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -I/usr//include -DHAVE_CONFIG_H -g -O2 -c /root/tdb-0.0.1/tdb.c -o tdb.lo
mkdir .libs
gcc -I. -I/root/tdb-0.0.1 -DPHP_ATOM_INC -I/root/tdb-0.0.1/include -I/root/tdb-0.0.1/main -I/root/tdb-0.0.1 -I/usr/include/php5 -I/usr/include/php5/main -I/usr/include/php5/TSRM -I/usr/include/php5/Zend -I/usr/include/php5/ext -I/usr/include/php5/ext/date/lib -D_LARGEFILE_SOURCE -D_FILE_OFFSET_BITS=64 -I/usr//include -DHAVE_CONFIG_H -g -O2 -c /root/tdb-0.0.1/tdb.c -fPIC -DPIC -o .libs/tdb.o
/root/tdb-0.0.1/tdb.c: In function 'zm_startup_tdb':
/root/tdb-0.0.1/tdb.c:88: error: 'TDB_NOSYNC' undeclared (first use in this function)
/root/tdb-0.0.1/tdb.c:88: error: (Each undeclared identifier is reported only once
/root/tdb-0.0.1/tdb.c:88: error: for each function it appears in.)
/root/tdb-0.0.1/tdb.c:89: error: 'TDB_SEQNUM' undeclared (first use in this function)
/root/tdb-0.0.1/tdb.c: In function 'zif_tdb_unlock':
/root/tdb-0.0.1/tdb.c:478: error: void value not ignored as it ought to be
make: *** [tdb.lo] Fehler 1
#7.1 Antony Dovgal (Homepage) on 2007-10-29 15:46 (Reply)
Well, then it's either wrong or old TDB.
I took & built it directly from Samba sources.
#8 René Leonhardt (Homepage) on 2008-01-11 10:32 (Reply)
Dear Antony,

good to see such progress with the PECL extension!

But I am wondering when new Windows builds will be available again?
The last version at
http://pecl4win.php.net/ext.php/php_memcache.dll
is 2.2.0 (build date is 2007-10-17).


Keep up the good work,
René
#8.1 Antony Dovgal (Homepage) on 2008-01-11 11:42 (Reply)
To be honest, I do not follow PECL/memcache development for a long time already.
It's maintained by Mikael Johansson these days and he seems to deal with it very well.

Regarding pecl4win builds, it seems that the extension wasn't built for a long time, I'll ask Edin what's wrong with his automatic builds.
#8.2 Antony Dovgal (Homepage) on 2008-01-11 17:12 (Reply)
Check it out, new build is there.

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