Redis Settings - redis.config

2023-02-21

Memory usage limits

Default value

32bit System: 3GB
64bit System: 0
0: Unlimited use of operating system virtual memory (swap)

When memory is full, remove the key according to the uninstall policy.

It must be greater than the maximum memory usage for one Cache.

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maxmemory 1gb


1k	1kb	1m	1mb	1g	1gb
1,000 bytes	1024 bytes	1,000,000 bytes	1024*1024 bytes	1,000,000,000 bytes	101210241024 bytes

Remove Policy

LFU support starting with Redis 4.0

Use the DEL command to remove the key.

DEL commands are executed in Main Thread.

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maxmemory-policy volatile-lru

noeviction

Do not run the uninstall policy.An error occurs when a write operation is performed with full memory.

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Servlet.service() for servlet [dispatcherServlet] in context with path [] threw exception [Request processing failed; nested exception is org.springframework.data.redis.RedisSystemException: Error in execution; nested exception is io.lettuce.core.RedisCommandExecutionException: OOM command not allowed when used memory > 'maxmemory'.] with root cause
io.lettuce.core.RedisCommandExecutionException: OOM command not allowed when used memory > 'maxmemory'.

volatile

Execute an uninstall policy on the EXPIRE SET (the set of keys with Expire set).

If there is no object to be removed, it acts like noeviction.


volatile-lru	The LRU algorithm removes the longest unreferenced key.(Recommended if you want to keep a single cache server, key permanently
volatile-lfu	The LFU algorithm removes the key with the least number of references.
volatile-random	Optionally remove the key.(Recommended if you want to keep a single cache server, key permanently
volatile-ttl	Remove the key with the least time-to-live (TTL) value (recommended if you use a different TTL for each key).

allkeys

Enable uninstall policy for all keys


allkeys-lru	The LRU algorithm removes the longest unreferenced key.(Recommended if only certain keys are used a lot in some cases)
allkeys-lfu	The LFU algorithm removes the key with the least number of references.
allkeys-random	Optionally remove the key.(Recommended if all keys are used uniformly)

Number of candidates to be removed

Compare and eliminate candidate groups that meet the elimination policy.

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maxmoery-samples 3

Asynchronous Removal (Redis 4.0)

Settings to prevent Blocking from occurring when the purge policy is run, removing multiple keys at once

If yes is set, LazyFreeThread is performed in the background using the UNLINK command rather than the DEL command.

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lazyfree-lazy-eviction yes

Use the UNLINK command to asynchronously remove the key when the uninstall policy is executed.

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lazyfree-lazy-expire yes

Use the UNLINK command to delete expired keys.

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lazyfree-lazy-server-del yes

Use UNLINK commands when executing SET or RENAME commands for keys that already exist.

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lazyfree-lazy-user-del yes

The DEL command works internally as a UNLINK command.(Redis 6.0)

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slave-lazy-flush yes

When replicating the entire data on the Master server to the Clone server, it is deleted with the FLUSHALL async command.Although synchronization speed is fast, additional memory may be required because new data is received without all existing data being deleted.

Reference

Key eviction

Cleaning up Redis server settings