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TransactionalStore
in package
implements KeyValueStore

In addition to buffering cache data in memory (see BufferedStore), this class will add transactional capabilities. Writes can be deferred by starting a transaction & all of them will only go out when you commit them.

This makes it possible to defer cache updates until we can guarantee it's safe (e.g. until we successfully committed everything to persistent storage).

There will be some trickery to make sure that, after we've made changes to cache (but not yet committed), we don't read from the real cache anymore, but instead serve the in-memory equivalent that we'll be writing to real cache when all goes well.

If a commit fails, all keys affected will be deleted to ensure no corrupt data stays behind.

Tags
author

Matthias Mullie [email protected]

copyright

Copyright (c) 2014, Matthias Mullie. All rights reserved

license

LICENSE MIT

Table of Contents

Interfaces

KeyValueStore
Interface for key-value storage engines.

Methods

__construct()  : mixed
__destruct()  : mixed
Roll back uncommitted transactions.
add()  : bool
Adds an item under new key.
begin()  : mixed
Initiate a transaction: this will defer all writes to real cache until commit() is called.
cas()  : bool
Replaces an item in 1 atomic operation, to ensure it didn't change since it was originally read, when the CAS token was issued.
commit()  : bool
Commits all deferred updates to real cache.
decrement()  : int|bool
Decrements a counter value, or sets an initial value if it does not yet exist.
delete()  : bool
Deletes an item from the cache.
deleteMulti()  : array<string|int, bool>
Deletes multiple items at once (reduced network traffic compared to individual operations).
flush()  : bool
Clears the entire cache.
get()  : mixed|bool
Retrieves an item from the cache.
getMulti()  : array<string|int, mixed>
Retrieves multiple items at once.
increment()  : int|bool
Increments a counter value, or sets an initial value if it does not yet exist.
replace()  : bool
Replaces an item.
rollback()  : bool
Roll back all scheduled changes.
set()  : bool
Stores a value, regardless of whether or not the key already exists (in which case it will overwrite the existing value for that key).
setMulti()  : array<string|int, bool>
Store multiple values at once.
touch()  : bool
Updates an item's expiration time without altering the stored value.

Methods

add()

Adds an item under new key.

public add(mixed $key, mixed $value[, mixed $expire = 0 ]) : bool
Parameters
$key : mixed
$value : mixed
$expire : mixed = 0

Time when item falls out of the cache: 0 = permanent (doesn't expires); under 2592000 (30 days) = relative time, in seconds from now; over 2592000 = absolute time, unix timestamp

Return values
bool

begin()

Initiate a transaction: this will defer all writes to real cache until commit() is called.

public begin() : mixed

cas()

Replaces an item in 1 atomic operation, to ensure it didn't change since it was originally read, when the CAS token was issued.

public cas(mixed $token, mixed $key, mixed $value[, mixed $expire = 0 ]) : bool
Parameters
$token : mixed

Token received from get() or getMulti()

$key : mixed
$value : mixed
$expire : mixed = 0

Time when item falls out of the cache: 0 = permanent (doesn't expires); under 2592000 (30 days) = relative time, in seconds from now; over 2592000 = absolute time, unix timestamp

Return values
bool

commit()

Commits all deferred updates to real cache.

public commit() : bool

If the any write fails, all subsequent writes will be aborted & all keys that had already been written to will be deleted.

Tags
throws
UnbegunTransaction
Return values
bool

decrement()

Decrements a counter value, or sets an initial value if it does not yet exist.

public decrement(mixed $key[, mixed $offset = 1 ][, mixed $initial = 0 ][, mixed $expire = 0 ]) : int|bool
Parameters
$key : mixed
$offset : mixed = 1

Value to decrement with

$initial : mixed = 0

Initial value (if item doesn't yet exist)

$expire : mixed = 0

Time when item falls out of the cache: 0 = permanent (doesn't expires); under 2592000 (30 days) = relative time, in seconds from now; over 2592000 = absolute time, unix timestamp

Return values
int|bool —

New value or false on failure

delete()

Deletes an item from the cache.

public delete(mixed $key) : bool
Parameters
$key : mixed
Return values
bool

deleteMulti()

Deletes multiple items at once (reduced network traffic compared to individual operations).

public deleteMulti(array<string|int, mixed> $keys) : array<string|int, bool>
Parameters
$keys : array<string|int, mixed>
Return values
array<string|int, bool>

get()

Retrieves an item from the cache.

public get(mixed $key[, mixed &$token = null ]) : mixed|bool
Parameters
$key : mixed
$token : mixed = null

Will be filled with the CAS token

Return values
mixed|bool —

Value, or false on failure

getMulti()

Retrieves multiple items at once.

public getMulti(array<string|int, mixed> $keys[, array<string|int, mixed> &$tokens = null ]) : array<string|int, mixed>
Parameters
$keys : array<string|int, mixed>
$tokens : array<string|int, mixed> = null

Will be filled with the CAS tokens, in [key => token] format

Return values
array<string|int, mixed> —

[key => value]

increment()

Increments a counter value, or sets an initial value if it does not yet exist.

public increment(mixed $key[, mixed $offset = 1 ][, mixed $initial = 0 ][, mixed $expire = 0 ]) : int|bool
Parameters
$key : mixed
$offset : mixed = 1

Value to increment with

$initial : mixed = 0

Initial value (if item doesn't yet exist)

$expire : mixed = 0

Time when item falls out of the cache: 0 = permanent (doesn't expires); under 2592000 (30 days) = relative time, in seconds from now; over 2592000 = absolute time, unix timestamp

Return values
int|bool —

New value or false on failure

replace()

Replaces an item.

public replace(mixed $key, mixed $value[, mixed $expire = 0 ]) : bool
Parameters
$key : mixed
$value : mixed
$expire : mixed = 0

Time when item falls out of the cache: 0 = permanent (doesn't expires); under 2592000 (30 days) = relative time, in seconds from now; over 2592000 = absolute time, unix timestamp

Return values
bool

set()

Stores a value, regardless of whether or not the key already exists (in which case it will overwrite the existing value for that key).

public set(mixed $key, mixed $value[, mixed $expire = 0 ]) : bool
Parameters
$key : mixed
$value : mixed
$expire : mixed = 0

Time when item falls out of the cache: 0 = permanent (doesn't expires); under 2592000 (30 days) = relative time, in seconds from now; over 2592000 = absolute time, unix timestamp

Return values
bool

setMulti()

Store multiple values at once.

public setMulti(array<string|int, mixed> $items[, mixed $expire = 0 ]) : array<string|int, bool>
Parameters
$items : array<string|int, mixed>

[key => value]

$expire : mixed = 0

Time when item falls out of the cache: 0 = permanent (doesn't expires); under 2592000 (30 days) = relative time, in seconds from now; over 2592000 = absolute time, unix timestamp

Return values
array<string|int, bool>

touch()

Updates an item's expiration time without altering the stored value.

public touch(mixed $key, mixed $expire) : bool
Parameters
$key : mixed
$expire : mixed

Time when item falls out of the cache: 0 = permanent (doesn't expires); under 2592000 (30 days) = relative time, in seconds from now; over 2592000 = absolute time, unix timestamp

Return values
bool 

        

        
    




    

    

                                

                

                                
    

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