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Databases · head to head

DynamoDB vs IBM Db2

DynamoDB logo

DynamoDB

Databases

AWS-only managed key-value and document database with fixed per-partition throughput limits and no ad hoc queries.

From
Free
Rated
-
Full reviewWebsite
IBM Db2 logo

IBM Db2

Databases

The AI-powered database built for demanding enterprise workloads

From
Free
Rated
-
Full reviewWebsite

The short version

  • Each has a real cost: DynamoDB access patterns must be designed into the key schema before launch; a query nobody anticipated needs a new global secondary index, which is a full extra copy of the projected attributes billed as storage and as writes, or an offline migration.; IBM Db2 cloud-based Db2 is newer than mainframe version; some legacy mainframe features not yet available in cloud
  • They diverge on capability: DynamoDB covers Managed and serverless, IBM Db2 covers AI-powered Query Optimization.
  • Prices and features above were last checked on 30 August 2026.

Where they differ

Only the attributes on which DynamoDB and IBM Db2 actually diverge.

Attributes where DynamoDB and IBM Db2 differ
AttributeDynamoDBIBM Db2
Pricing modelusage-basedUnknown
PlatformsAWSIBM Cloud, On-premises (mainframe), Linux, UNIX
Founded20061983

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 DynamoDB

  • Managed and serverless
  • Predictable latency
  • On-demand or provisioned capacity
  • Global secondary indexes
  • Transactions
  • DynamoDB Streams
  • Global tables
  • Point-in-time recovery

Only in IBM Db2

  • AI-powered Query Optimization
  • Data Virtualization
  • Advanced Compression
  • pureScale Clustering
  • BLU Acceleration
  • Workload Management
  • Federated Queries
  • IBM Cloud

What people use each for

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

DynamoDB

  • High-volume keyed workloads such as sessions, shopping carts, device state or user profiles where the access pattern is fixed and knownnot IBM Db2
  • Traffic that spikes unpredictably, where on-demand capacity absorbs a burst without a capacity-planning exercisenot IBM Db2
  • Serverless applications on Lambda, where an HTTP-based datastore avoids the connection pooling problem relational databases havenot IBM Db2
  • Event or telemetry ingestion where writes vastly outnumber reads and each record is retrieved by a known identifiernot IBM Db2

IBM Db2

  • Transaction processingnot DynamoDB
  • Data storagenot DynamoDB
  • Application backendnot DynamoDB
  • Reportingnot DynamoDB
  • Data analyticsnot DynamoDB

Where each one falls short

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

DynamoDB

  • Access patterns must be designed into the key schema before launch; a query nobody anticipated needs a new global secondary index, which is a full extra copy of the projected attributes billed as storage and as writes, or an offline migration.
  • Global secondary indexes are eventually consistent and cannot be read strongly, so a read-after-write against an index can legitimately miss the item that was just written, and application code must be written to tolerate that.
  • Per-partition throughput is capped at roughly 3,000 read and 1,000 write units, so a hot key throttles even when the table has spare capacity overall, and the only real fix is changing the key design to spread the load.
  • Items are limited to 400 KB and query results paginate at 1 MB, so large or list-shaped data has to be split, offloaded to S3 with a pointer, or read through pagination loops that complicate every consumer.
  • It runs only on AWS and the API is proprietary rather than a standard, so moving the data layer means rewriting it; ScyllaDB's Alternator is the only meaningfully compatible target and it brings a much smaller ecosystem.

IBM Db2

  • Cloud-based Db2 is newer than mainframe version; some legacy mainframe features not yet available in cloud
  • Pricing complexity with hourly billing for compute and storage can result in unpredictable costs
  • Less community support and documentation compared to open-source alternatives like PostgreSQL
  • Requires IBM expertise and tools for optimal configuration and tuning
  • Migration from mainframe Db2 to cloud Db2 requires careful planning and testing

Pricing, plan by plan

DynamoDB

Free
  • On-Demand Capacity$null/usage-based
    • Pay-per-request pricing with automatic scaling
    • Read: 0.5 RRU per 4 KB (eventually consistent), 1 RRU per 4 KB (strongly consistent), 2 RRU per 4 KB (transactional)
    • Write: 1 WRU per 1 KB
  • Provisioned Capacity$null/hourly
    • Fixed hourly charges based on reserved capacity
    • RCU rate: $0.00013 per hour (Standard)
    • WCU rate: $0.00065 per hour (Standard)
  • Standard Table Class Storage$0.25/per GB/month
    • $0.25 per GB/month after free tier
    • First 25 GB free per month (free tier)
  • Standard-Infrequent Access Table Class$0.1/per GB/month
    • $0.10 per GB/month

IBM Db2

Free
  • Free TierFree
    • Entry-level exploration
    • Limited resources
  • Standard$99/month
    • Production-ready workloads
    • Shared computing resources
  • Enterprise$969/month
    • Dedicated computing resources
    • Enhanced capabilities

Which should you pick?

Choose DynamoDB if

  • You need managed and serverless.
  • You want to start without paying.
  • You work on AWS.
  • You also want predictable latency.
DynamoDB review

Choose IBM Db2 if

  • You need ai-powered query optimization.
  • You want to start without paying.
  • You work on IBM Cloud, On-premises (mainframe), Linux, UNIX.
  • You also want data virtualization.
IBM Db2 review

Questions people ask

Is DynamoDB or IBM Db2 better?
Neither clearly leads. DynamoDB starts at Free and IBM Db2 at Free, and user ratings are close enough to be indistinguishable. Choose on capability and platform support.
Which is cheaper, DynamoDB or IBM Db2?
DynamoDB starts at Free and IBM Db2 at Free.
Does DynamoDB or IBM Db2 run on more platforms?
DynamoDB runs on AWS. IBM Db2 runs on IBM Cloud, On-premises (mainframe), Linux, UNIX.
Can I use DynamoDB for free?
Both have a free tier, so you can try either at no cost before committing.
What is DynamoDB best used for?
DynamoDB is most often used for high-volume keyed workloads such as sessions, shopping carts, device state or user profiles where the access pattern is fixed and known, traffic that spikes unpredictably, where on-demand capacity absorbs a burst without a capacity-planning exercise, serverless applications on lambda, where an http-based datastore avoids the connection pooling problem relational databases have, event or telemetry ingestion where writes vastly outnumber reads and each record is retrieved by a known identifier. Of those, high-volume keyed workloads such as sessions, shopping carts, device state or user profiles where the access pattern is fixed and known and traffic that spikes unpredictably, where on-demand capacity absorbs a burst without a capacity-planning exercise are not what IBM Db2 is typically brought in for.
What can DynamoDB do that IBM Db2 cannot?
DynamoDB covers Managed and serverless, Predictable latency, On-demand or provisioned capacity, Global secondary indexes. IBM Db2 covers AI-powered Query Optimization, Data Virtualization, Advanced Compression, pureScale Clustering.

Answered from the vendors’ own pages

DynamoDB: On-demand or provisioned capacity?

On-demand suits unpredictable or spiky traffic and removes capacity planning. Provisioned with autoscaling is considerably cheaper for steady high-volume workloads. Tables can be switched between them, though not arbitrarily often.

IBM Db2: What is IBM Db2?

IBM Db2 is a cloud-based relational database management system designed for enterprise data management. It evolved from IBM's research into relational databases in the 1970s and launched for mainframe systems in 1983.

Source
DynamoDB: Can I run DynamoDB outside AWS?

No. DynamoDB Local exists for development and testing only. For a production-compatible alternative elsewhere, ScyllaDB's Alternator implements the DynamoDB API, but it is a different system with a different ecosystem.

IBM Db2: What are the pricing tiers for IBM Db2 cloud database?

IBM Db2 offers a perpetually free tier for exploration, Standard tier starting at $99/month (billed hourly), and Enterprise tier starting at $969/month (billed hourly). Storage costs $0.000282 per GB per hour across tiers.

Source
DynamoDB: Can I run ad hoc queries or analytics?

Not on the table itself. Scans are slow and expensive at scale. The usual pattern is to export to S3 or stream changes out and query them in Athena, Redshift or another analytical engine.

IBM Db2: Does Db2 support automatic failover and disaster recovery?

Yes. Db2 includes HADR (High Availability Disaster Recovery) with multizone region support, point-in-time recovery, built-in self-service snapshots, and geo-replicated data recovery backups.

Source
DynamoDB: Is single-table design necessary?

It is the pattern that gets the most from DynamoDB when access patterns are well known, because it lets related items be retrieved in one query. It also makes the model harder to evolve, so many teams reasonably choose multiple simpler tables and accept extra requests.

IBM Db2: Can Db2 scale horizontally?

Yes. Db2 supports both vertical and horizontal scaling through its pureScale architecture, allowing it to handle growing data volumes while maintaining performance for mission-critical applications.

Source
DynamoDB: What are the real limits I should design around?

400 KB per item, 1 MB per query or scan page, 100 items per transaction, roughly 3,000 read and 1,000 write units per partition, and eventual consistency on global secondary indexes.

IBM Db2: How long has DB2 been in production?

DB2 launched in June 1983 on the MVS operating system and has operated for over 40 years. It remains the foundational database for the largest enterprises globally, managing data for financial, retail, healthcare, and insurance institutions.

Source
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