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Databases · head to head

Memcached vs Apache Flink

Memcached logo

Memcached

Databases

Distributed memory object caching system

From
Free
Rated
-
Full reviewWebsite
Apache Flink logo

Apache Flink

Databases

Stateful stream processing at scale

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: Memcached no persistence at all: restart a node and its cache is gone, which every design must assume; Apache Flink genuinely difficult: event time, watermarks and state backends are a real conceptual load before anything works
  • They diverge on capability: Memcached covers In-memory key-value cache, Apache Flink covers Event-time processing.

Where they differ

Only the attributes on which Memcached and Apache Flink actually diverge.

Attributes where Memcached and Apache Flink differ
AttributeMemcachedApache Flink
Pricing modelOpen source, no licence fee; managed cloud billed separatelyOpen source, no licence fee; managed services billed separately
PlatformsLinux, macOS, Windows, Docker, Self-hostedLinux, Kubernetes, Docker, Self-hosted

Identical on both: starting price (Free), free tier (Yes), user rating (Not yet rated), category (Databases).

What each one covers

Drawn from each product's published feature list. An absence here means we hold no record of it - not that the product lacks it.

Only in Memcached

  • In-memory key-value cache
  • Multithreaded
  • Client-side sharding
  • Predictable memory use

Only in Apache Flink

  • Event-time processing
  • Exactly-once state
  • Batch and stream
  • SQL interface

What people use each for

The jobs each tool is most often brought in to do.

Memcached

  • Caching expensive database query results to cut loadnot Apache Flink
  • Session storage where losing sessions on restart is acceptablenot Apache Flink
  • Fronting an API whose responses are costly and change slowlynot Apache Flink

Apache Flink

  • Real-time aggregations and dashboards computed over an event streamnot Memcached
  • Fraud and anomaly detection where patterns span a time windownot Memcached
  • Joining two live streams where events arrive out of ordernot Memcached

Where each one falls short

Documented limitations, not opinions. Every one is a constraint you would hit in normal use.

Memcached

  • No persistence at all: restart a node and its cache is gone, which every design must assume
  • No replication or failover, so losing a node loses that share of the cache
  • Only simple key-value, with none of the lists, sorted sets or streams Redis offers
  • Values are capped at 1MB by default, which surprises teams caching large documents

Apache Flink

  • Genuinely difficult: event time, watermarks and state backends are a real conceptual load before anything works
  • Operationally heavy — job managers, task managers, checkpoint storage and state size are all yours to run and tune
  • State grows with the workload, and large state changes recovery time and cost significantly
  • Overkill where a scheduled batch job would answer the same question

Pricing, plan by plan

Memcached

Free
  • MemcachedFree
    • Full functionality
    • Self-hosted
    • No usage limits

Apache Flink

Free
  • Apache FlinkFree
    • Full functionality
    • Self-hosted
    • No usage limits

Which should you pick?

Choose Memcached if

  • You need in-memory key-value cache.
  • You want to start without paying.
  • You work on Linux, macOS, Windows, Docker, Self-hosted.
  • You also want multithreaded.
Memcached review

Choose Apache Flink if

  • You need event-time processing.
  • You want to start without paying.
  • You work on Linux, Kubernetes, Docker, Self-hosted.
  • You also want exactly-once state.
Apache Flink review

Questions people ask

Is Memcached or Apache Flink better?
Neither clearly leads. Memcached starts at Free and Apache Flink at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Memcached or Apache Flink?
Memcached starts at Free and Apache Flink at Free.
Does Memcached or Apache Flink run on more platforms?
Memcached runs on Linux, macOS, Windows, Docker, Self-hosted. Apache Flink runs on Linux, Kubernetes, Docker, Self-hosted.
Can I use Memcached for free?
Both have a free tier, so you can try either at no cost before committing.
What is Memcached best used for?
Memcached is most often used for caching expensive database query results to cut load, session storage where losing sessions on restart is acceptable, fronting an api whose responses are costly and change slowly. Of those, caching expensive database query results to cut load and session storage where losing sessions on restart is acceptable are not what Apache Flink is typically brought in for.
What can Memcached do that Apache Flink cannot?
Memcached covers In-memory key-value cache, Multithreaded, Client-side sharding, Predictable memory use. Apache Flink covers Event-time processing, Exactly-once state, Batch and stream, SQL interface.

Answered from the vendors’ own pages

Memcached: Is Memcached free?

Yes, open source with no licence fee.

Apache Flink: Is Apache Flink free?

Yes, open source under the Apache Software Foundation. Managed services such as Amazon Managed Service for Apache Flink are billed separately.

Memcached: Memcached or Redis?

Memcached is a pure cache: simpler, multithreaded and very predictable. Redis adds persistence, replication and rich data structures, which is why it is the default choice unless you specifically want a cache and nothing more.

Apache Flink: Flink or Kafka?

They are complementary rather than alternatives. Kafka moves and stores events; Flink computes over them with windowing, joins and durable state.

Memcached: Does Memcached persist data?

No. Everything is in memory and lost on restart, by design.

Apache Flink: What is event-time processing?

Computing based on when an event actually occurred rather than when it arrived. It is what makes results correct when data is late or out of order, and it is the main reason Flink is harder than it looks.

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