igbinary
Igbinary is a drop in replacement for the standard php serializer.
Instead of the time and space consuming textual representation used by PHP's serialize,
igbinary stores php data structures in a compact binary form.
Memory savings are significant when using memcached, APCu, or similar memory based storages for serialized data.
The typical reduction in storage requirements are around 50%.
The exact percentage depends on your data.
Unserialization performance is at least on par with the standard PHP serializer, and is much faster for repetitive data.
Serialization performance depends on the igbinary.compact_strings option which enables
duplicate string tracking.
String are inserted to a hash table, which adds some overhead when serializing.
In usual scenarios this does not have much of an impact,
because the typical usage pattern is "serialize rarely, unserialize often".
With the compact_strings option enabled,
igbinary is usually a bit slower than the standard serializer.
Without it, igbinary is a bit faster.
Features
- Support for the same data types as the standard PHP serializer: null, bool, int,
float, string, array and object. __autoload&unserialize_callback_func__sleep&__wakeup__serialize&__unserialize(only used in php 7.4+)- Serializable -interface
- Data portability between platforms (32/64bit, endianness)
- Tested on Linux amd64, Linux ARM, Mac OSX x86, HP-UX PA-RISC and NetBSD sparc64
- Hooks up to the APCu in-memory key-value store as a serialization handler.
- Compatible with 7.0 – 7.4 (The older igbinary 2.x releases support 5.2 – 5.6, 7.0 – 7.3)
Implementation details
Storing complex PHP data structures such as arrays of associative arrays
with the standard PHP serializer is not very space efficient.
The main reasons of this inefficiency are listed below, in order of significance (at least in our applications):
- Array keys, property names, and class names are repeated redundantly.
- Numerical values are plain text.
- Human readability adds some overhead.
Igbinary uses two strategies to minimize the size of the serialized
output.
-
Repeated strings are stored only once (this also includes class and property names).
Collections of objects benefit significantly from this.
See theigbinary.compact_stringsoption. -
Integer values are stored in the smallest primitive data type available:
123 =int8_t,
1234 =int16_t,
123456 =int32_t
... and so on. -
( Well, it is not human readable ;)
How to use
Add the following lines to your php.ini:
; Load igbinary extension
extension=igbinary.so
; Use igbinary as session serializer
session.serialize_handler=igbinary
; Enable or disable compacting of duplicate strings
; The default is On.
igbinary.compact_strings=On
; If uncommented, use igbinary as the serializer of APCu
; (APCu 5.1.10 or newer is strongly recommended)
;apc.serializer=igbinary
Then, in your php code, replace serialize and unserialize function calls
with igbinary_serialize and igbinary_unserialize.
Installing
Linux
If PHP was installed through your package manager,
the package manager may also contain prebuilt packages for igbinary
(with a package name similar to php-igbinary)
Igbinary may also be installed with the command pecl install igbinary (You will need to enable igbinary in php.ini)
Alternately, you may wish to build from source
MacOS
pecl install igbinary is the recommended installation method (You will need to enable igbinary in php.ini)
Alternately, you may wish to build from source.
Installing on Windows
Prebuilt DLLs can be downloaded from PECL.
If you are a contributor to/packager of igbinary, or need to build from source, see WINDOWS.md
Building from source
-
phpize -
./configure- With GCC:
./configure CFLAGS="-O2 -g" --enable-igbinary - With ICC (Intel C Compiler)
./configure CFLAGS=" -no-prec-div -O3 -xO -unroll2 -g" CC=icc --enable-igbinary - With clang:
./configure CC=clang CFLAGS="-O0 -g" --enable-igbinary
- With GCC:
-
make -
make test -
make install -
igbinary.sois installed to the default extension directory
Bugs & Contributions
Mailing list for bug reports and other development discussion can be found
at http://groups.google.com/group/igbinary
File bug reports at
https://github.com/igbinary/igbinary/issues
The preferred way to contribute is with pull requests.
Feel free to fork this at http://github.com/igbinary/igbinary
See TESTING.md for advice for testing patches.
Utilizing in other extensions
Igbinary can be called from other extensions fairly easily. Igbinary installs
its header file to ext/igbinary/igbinary.h. There are just two straightforward
functions: igbinary_serialize and igbinary_unserialize. Look at igbinary.h for
prototypes and usage.
Add PHP_ADD_EXTENSION_DEP(yourextension, igbinary) to your config.m4 in case
someone wants to compile both of them statically into php.
Trivia
Where does the name "igbinary" come from? There was once a similar project
called fbinary but it has disappeared from the Internet a long time ago. Its
architecture wasn't particularly clean either. IG is an abbreviation for a
Finnish social networking site IRC-Galleria (http://irc-galleria.net/)