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Databases · head to head

Apache Flink vs Memcached

Apache Flink logo

Apache Flink

Databases

Stateful stream processing at scale

From
Free
Rated
-
Full reviewWebsite
Memcached logo

Memcached

Databases

Distributed memory object caching system

From
Free
Rated
-
Full reviewWebsite

The short version

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

Where they differ

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

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

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

Only in Memcached

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

What people use each for

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

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

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

Where each one falls short

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

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

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

Pricing, plan by plan

Apache Flink

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

Memcached

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

Which should you pick?

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

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

Questions people ask

Is Apache Flink or Memcached better?
Neither clearly leads. Apache Flink starts at Free and Memcached at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, Apache Flink or Memcached?
Apache Flink starts at Free and Memcached at Free.
Does Apache Flink or Memcached run on more platforms?
Apache Flink runs on Linux, Kubernetes, Docker, Self-hosted. Memcached runs on Linux, macOS, Windows, Docker, Self-hosted.
Can I use Apache Flink for free?
Both have a free tier, so you can try either at no cost before committing.
What is Apache Flink best used for?
Apache Flink is most often used for real-time aggregations and dashboards computed over an event stream, fraud and anomaly detection where patterns span a time window, joining two live streams where events arrive out of order. Of those, real-time aggregations and dashboards computed over an event stream and fraud and anomaly detection where patterns span a time window are not what Memcached is typically brought in for.
What can Apache Flink do that Memcached cannot?
Apache Flink covers Event-time processing, Exactly-once state, Batch and stream, SQL interface. Memcached covers In-memory key-value cache, Multithreaded, Client-side sharding, Predictable memory use.

Answered from the vendors’ own pages

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: Is Memcached free?

Yes, open source with no licence fee.

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: 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: 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.

Memcached: Does Memcached persist data?

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

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