API Reference Guide > Zend OPcache Configuration Directives

Zend OPcache - Configuration Directives

This topic lists all the configuration directives for Zend OPcache.

Configuration Directives Summary

The table below is a summary of all the Zend OPcache configuration directives, and displays the directive name, its default value, and a description:

Directive	Default Value	Description
opcache.enable	1	Enables the opcode cache. When disabled, code is not optimised and cached.
opcache.file_update_protection	2	Prevents caching files that are less than this number of seconds old.
opcache.restrict_api		Use OPCache API only from path starting the specified string.
opcache.enable_cli	0	Enables the opcode cache for the CLI version of PHP. This is mostly useful for testing and debugging.
opcache.use_cwd	1	If set, use the current directory as a part of the script key.
opcache.validate_timestamps	1	If enabled, OPcache checks the file timestamps and updates the cache accordingly.
opcache.revalidate_freq	2	How often to check file timestamps for changes to the shared memory storage allocation.
opcache.revalidate_path	0	Enables or disables file search in include_path optimization
opcache.inherited_hack	1	Enable this hack as a workaround for "can't redeclare class" errors
opcache.dups_fix	0	This hack should only be enabled to work around "Cannot redeclare class" errors.
opcache.log_verbosity_level	1	The verbosity of the OPcache log.
opcache.memory_consumption	64	The OPcache shared memory storage size. The amount of memory for storing precompiled PHP code in Mbytes.
opcache.interned_strings_buffer	4	The amount of memory used to store interned strings, in megabytes. This configuration directive is ignored in PHP < 5.3.0.
opcache.max_accelerated_files	2000	The maximum number of keys (scripts) in the OPcache hash table.
opcache.max_wasted_percentage	5	The maximum percentage of "wasted" memory until a restart is scheduled.
opcache.consistency_checks	0	Check the cache checksum every N requests.
opcache.force_restart_timeout	180	Time duration (in seconds) for waiting for a scheduled restart to begin if the cache is not being accessed.
opcache.preferred_memory_model		Shared memory model to use.
opcache.blacklist_filename		The location of the OPcache blacklist file.
opcache.error_log		The location of the OPcache error log file.
opcache.protect_memory	0	Protects shared memory from unexpected writes while executing scripts. This is useful for internal debugging only.
opcache.save_comments	1	If disabled, all PHPDoc comments are dropped from the code to reduce the size of the optimized code.
opcache.load_comments	1	If disabled, documentation comments won't be loaded from the opcode cache even if they exist.
opcache.fast_shutdown	0	If enabled, a fast shutdown sequence is used for the accelerated code.
opcache.optimization_level	0xffffffff	A bitmask, where each bit enables or disables the appropriate OPcache passes.
opcache.mmap_base		Mapping base of shared memory segments.
opcache.enable_file_override	0	Allow file existence caching.
opcache.max_file_size	0	The maximum file size that will be cached, in bytes. If this is 0, all files will be cached.
zend_optimizerplus.max_wasted_percentage	5	The maximum percentage of "wasted" memory until a restart is scheduled.

Configuration Directives Details

The list below contains information for all the available configuration directives for Zend OPcache: their description, type, units, default value, modification scope, and the Zend Server version they became available in.

opcache.enable

Enables the opcode cache. When disabled, code is not optimised and cached.

Default Value: 1

Type: boolean

Modification Scope: ZEND_INI_SYSTEM

Available Since Version: 6.3

opcache.file_update_protection

Prevents caching files that are less than this number of seconds old. It protects from caching of incompletely updated files. In case all file updates on your site are atomic, you may increase performance setting it to "0"".

Default Value: 2

Type: int

Available Since Version: 6.3

opcache.restrict_api

Allows calling OPcache API functions only from PHP scripts which path is started from specified string. The default "" means no restriction.

Default Value:

Type: string

Available Since Version: 6.3

opcache.enable_cli

Enables the opcode cache for the CLI version of PHP. This is mostly useful for testing and debugging.

Default Value: 0

Type: boolean

Modification Scope: ZEND_INI_SYSTEM

Available Since Version: 6.3

opcache.use_cwd

If enabled, OPcache appends the current working directory to the script key, thereby eliminating possible collisions between files with the same base name. Disabling this directive improves performance, but may break existing applications.

Default Value: 1

Type: boolean

Modification Scope: ZEND_INI_SYSTEM

Available Since Version: 6.3

opcache.validate_timestamps

If enabled, OPcache will check for updated scripts every opcache.revalidate_freq seconds. When this directive is disabled, you must reset OPcache manually via opcache_reset(), opcache_invalidate() or by restarting the Web server for changes to the filesystem to take effect.

Default Value: 1

Type: boolean

Modification Scope: ZEND_INI_ALL

Available Since Version: 6.3

opcache.revalidate_freq

How often to check script timestamps for updates, in seconds. 0 will result in OPcache checking for updates on every request. This configuration directive is ignored if opcache.validate_timestamps if disabled.

Default Value: 2

Units: seconds

Type: int

Modification Scope: ZEND_INI_ALL

Available Since Version: 6.3

opcache.revalidate_path

If disabled, existing cached files using the same include_path will be reused. Thus, if a file with the same name is elsewhere in the include_path, it won't be found.

Default Value: 0

Type: boolean

Modification Scope: ZEND_INI_ALL

Available Since Version: 6.3

opcache.inherited_hack

The OPcache stores the places where DECLARE_CLASS opcodes use inheritance (These are the only opcodes that can be executed by PHP, but which may not be executed because the parent class is missing due to optimization). When the file is loaded, OPcache tries to bind the inherited classes by using the current environment. The problem with this scenario is that, while the DECLARE_CLASS opcode may not be needed for the current script, if the script requires that the opcode at least be defined, it may not run. The default for this directive is disabled, which means that optimization is active. In php-5.3 and above this hack is not needed anymore and this setting has no effect.

Default Value: 1

Type: boolean

Modification Scope: ZEND_INI_SYSTEM

Available Since Version: 6.3

opcache.dups_fix

This hack should only be enabled to work around "Cannot redeclare class" errors.

Default Value: 0

Type: boolean

Modification Scope: ZEND_INI_ALL

Available Since Version: 6.3

opcache.log_verbosity_level

The log verbosity level. By default, only fatal errors (level 0) and errors (level 1) are logged. Other levels available are warnings (level 2), information messages (level 3) and debug messages (level 4).

Default Value: 1

Type: int

Modification Scope: ZEND_INI_SYSTEM

Available Since Version: 6.3

opcache.memory_consumption

The OPcache shared memory storage size. The amount of memory for storing precompiled PHP code in Mbytes.

Default Value: 64

Units: MBytes

Type: int

Modification Scope: ZEND_INI_SYSTEM

Available Since Version: 6.3

opcache.interned_strings_buffer

The amount of memory used to store interned strings, in megabytes. This configuration directive is ignored in PHP < 5.3.0.

Default Value: 4

Units: MBytes

Type: int

Modification Scope: ZEND_INI_SYSTEM

Available Since Version: 6.3

opcache.max_accelerated_files

The number is actually the the first one in the following set of prime numbers that is bigger than the one supplied: { 223, 463, 983, 1979, 3907, 7963, 16229, 32531, 65407, 130987 }. Only numbers between 200 and 100000 are allowed.

Default Value: 2000

Type: int

Modification Scope: ZEND_INI_SYSTEM

Available Since Version: 6.3

opcache.max_wasted_percentage

The maximum percentage of "wasted" memory until a restart is scheduled.

Default Value: 5

Units: %

Type: int

Modification Scope: ZEND_INI_SYSTEM

Available Since Version: 6.3

opcache.consistency_checks

If non-zero, OPcache will verify the cache checksum every N requests, where N is the value of this configuration directive. This should only be enabled when debugging, as it will impair performance.

Default Value: 0

Type: int

Modification Scope: ZEND_INI_ALL

Available Since Version: 6.3

opcache.force_restart_timeout

The length of time to wait for a scheduled restart to begin if the cache isn't active, in seconds. If the timeout is hit, then OPcache assumes that something is wrong and will kill the processes holding locks on the cache to permit a restart. If opcache.log_verbosity_level is set to 3 or above, an error will be recorded in the error log when this occurs.

Default Value: 180

Units: seconds

Type: int

Modification Scope: ZEND_INI_SYSTEM

Available Since Version: 6.3

opcache.preferred_memory_model

The preferred memory model for OPcache to use. If left empty, OPcache will choose the most appropriate model, which is the correct behaviour in virtually all cases. Possible values include mmap, shm, posix and win32.

Default Value:

Type: string

Modification Scope: ZEND_INI_ALL

Available Since Version: 6.3

opcache.blacklist_filename

The location of the OPcache blacklist file. A blacklist file is a text file containing the names of files that should not be accelerated, one per line. Wildcards are allowed, and prefixes can also be provided. Lines starting with a semi-colon are ignored as comments.

Default Value:

Type: string

Modification Scope: ZEND_INI_SYSTEM

Available Since Version: 6.3

opcache.error_log

The error log for OPcache errors. An empty string is treated the same as stderr, and will result in logs being sent to standard error (which will be the Web server error log in most cases).

Default Value:

Type: string

Modification Scope: ZEND_INI_SYSTEM

Available Since Version: 6.3

opcache.protect_memory

Protects shared memory from unexpected writes while executing scripts. This is useful for internal debugging only.

Default Value: 0

Type: boolean

Modification Scope: ZEND_INI_SYSTEM

Available Since Version: 6.3

opcache.save_comments

If disabled, all documentation comments will be discarded from the opcode cache to reduce the size of the optimised code. Disabling this configuration directive may break applications and frameworks that rely on comment parsing for annotations, including Doctrine, Zend Framework 2 and PHPUnit.

Default Value: 1

Type: boolean

Modification Scope: ZEND_INI_SYSTEM

Available Since Version: 6.3

opcache.load_comments

If disabled, documentation comments won't be loaded from the opcode cache even if they exist. This can be used with opcache.save_comments to only load comments for applications that require them.

Default Value: 1

Type: boolean

Modification Scope: ZEND_INI_SYSTEM

Available Since Version: 6.3

opcache.fast_shutdown

If enabled, a fast shutdown sequence is used that doesn't free each allocated block, but relies on the Zend Engine memory manager to deallocate the entire set of request variables en masse.

Default Value: 0

Type: boolean

Modification Scope: ZEND_INI_SYSTEM

Available Since Version: 6.3

opcache.optimization_level

A bitmask, where each bit enables or disables the appropriate OPcache passes.

Default Value: 0xffffffff

Type: int

Modification Scope: ZEND_INI_SYSTEM

Available Since Version: 6.3

opcache.mmap_base

The base used for shared memory segments on Windows. All PHP processes have to map shared memory into the same address space. Using this directive allows "Unable to reattach to base address" errors to be fixed.

Applicable On: Windows

Default Value:

Type: string

Modification Scope: ZEND_INI_SYSTEM

Available Since Version: 6.3

opcache.enable_file_override

When enabled, the opcode cache will be checked for whether a file has already been cached when file_exists(), is_file() and is_readable() are called. This may increase performance in applications that check the existence and readability of PHP scripts, but risks returning stale data if opcache.validate_timestamps is disabled.

Default Value: 0

Type: boolean

Modification Scope: ZEND_INI_SYSTEM

Available Since Version: 6.3