Opcache in php 5.5 not caching anything

Question

I have a LAMP system on Ubuntu 14.04

I have made changes in the php.ini at the path /etc/php5/apache2/php.ini I have made the following changes in php.ini

opcache.enable=1
opcache.enable_cli=1
opcache.memory_consumption=128
opcache.interned_strings_buffer=8
opcache.max_accelerated_files=4000
opcache.revalidate_freq=120

The reason I put opcache.enable_cli=1 is because i was getting the following error in php -i

Opcode Caching => Disabled
Optimization => Disabled
Startup Failed => Opcode Caching is disabled for CLI

opcache.enable => On => On
opcache.enable_cli => Off => Off

After puting opcache.enable_cli=1, I get the following in php -i

Zend OPcache

Opcode Caching => Up and Running
Optimization => Enabled
Startup => OK
Shared memory model => mmap
Cache hits => 0
Cache misses => 0
Used memory => 10707944
Free memory => 123509784
Wasted memory => 0
Cached scripts => 0
Cached keys => 0
Max keys => 3907
OOM restarts => 0
Hash keys restarts => 0
Manual restarts => 0

Directive => Local Value => Master Value
opcache.blacklist_filename => no value => no value
opcache.consistency_checks => 0 => 0
opcache.dups_fix => Off => Off
opcache.enable => On => On
opcache.enable_cli => On => On
opcache.enable_file_override => Off => Off
opcache.error_log => no value => no value
opcache.fast_shutdown => 1 => 1
opcache.file_update_protection => 2 => 2
opcache.force_restart_timeout => 180 => 180
opcache.inherited_hack => On => On
opcache.interned_strings_buffer => 8 => 8
opcache.load_comments => 1 => 1
opcache.log_verbosity_level => 1 => 1
opcache.max_accelerated_files => 2500 => 2500
opcache.max_file_size => 0 => 0
opcache.max_wasted_percentage => 5 => 5
opcache.memory_consumption => 128 => 128
opcache.optimization_level => 0xFFFFFFFF => 0xFFFFFFFF
opcache.preferred_memory_model => no value => no value
opcache.protect_memory => 0 => 0
opcache.restrict_api => no value => no value
opcache.revalidate_freq => 90 => 90
opcache.revalidate_path => Off => Off
opcache.save_comments => 1 => 1
opcache.use_cwd => On => On
opcache.validate_timestamps => On => On

Opcache is running but it is not caching anything. After a page loads for the first time and then I refresh the page within 90 seconds I see a different page

Answer 1

You're misunderstanding what opcache is. PHP files are just plain text. They're not machine code. So PHP has to parse that text and generate machine code (operation code, or opcode for short). Once it has that opcode, it can then run your program.

Opcache simply stores the opcodes. It helps save overhead when the underlying code isn't changing a lot.

What you're talking about is something like output caching , where the web server stores what it sends to the clients.