Quotas and limits in Amazon QLDB
This section describes the current quotas, also referred to as limits, in Amazon QLDB.
Default quotas
QLDB has the following default quotas, as also listed at Amazon QLDB endpoints and quotas in the AWS General Reference. These quotas are per AWS account per Region. To request a quota increase for your account in a Region, use the Service Quotas console.
Sign in to the AWS Management Console and open the Service Quotas console at https://console.aws.amazon.com/servicequotas/
| Resource | Default quota |
|---|---|
| The maximum number of active ledgers that you can create in this account in the current Region | 5 |
| The maximum number of active journal exports to Amazon S3 per ledger | 2 |
| The maximum number of active journal streams to Kinesis Data Streams per ledger | 5 |
Fixed quotas
In addition to default quotas, QLDB has the following fixed quotas per ledger. These quotas can't be increased by using Service Quotas:
| Resource | Fixed quota |
|---|---|
| Number of concurrent active sessions | 1500 |
| Number of active tables | 20 |
Number of total tables (active and inactive) NoteIn QLDB, dropped tables are considered inactive and count against this total quota. |
40 |
| Number of indexes per table | 5 |
| Number of documents in a transaction | 40 |
| Number of revisions to redact in a transaction | 1 |
Document size (encoded in
IonBinary format) |
128 KB |
Statement parameter size (IonBinary format) |
128 KB |
Statement parameter size (IonText format) |
1 MB |
| Statement string length | 100,000 characters |
| Transaction size | 4 MB |
| Transaction timeout | 30 seconds |
| Expiration period for completed journal export jobs | 7 days |
| Expiration period for terminal journal streams | 7 days |
Ledger quota
To request a ledger quota increase for your account in a Region, you can use the Service Quotas console.
Open the Service Quotas console at https://console.aws.amazon.com/servicequotas/
Some QLDB use cases require an expanding number of ledgers per AWS account per
Region based on business growth. For example, you might need to create dedicated ledgers
to isolate customers or data. In this case, consider leveraging a multi-account
architecture to work with QLDB quotas. For more information, refer to
Account Silo Isolation in the AWS whitepaper SaaS Tenant Isolation Strategies
Document size
The maximum size for a document that is encoded in the IonBinary format
is 128 KB. We can't provide an exact limit for the size of a document in
IonText format because the conversion from text to binary varies
significantly based on the structure of each document. QLDB supports documents with
open content, so each unique document structure alters the size calculation.
Transaction size
The maximum size for a transaction in QLDB is 4 MB. The size of a transaction is calculated based on the sum of the following factors.
- Deltas
-
The document changes that are generated by all the statements within the transaction. In a transaction that impacts several documents, the total delta size is the sum of each affected document's individual delta.
- Metadata
-
The system-generated transaction metadata that is associated with each affected document.
- Indexes
-
If an index is defined on a table that is affected by the transaction, the associated index entry also generates a delta.
- History
-
Because all document revisions are persisted in QLDB, all transactions also append to the history.
Inserts – Every document inserted into a table also has a copy inserted into its history table. For example, a newly inserted 100 KB document generates a minimum of 200 KB of deltas in a transaction. (This is a rough estimate that doesn't include metadata or indexes.)
Updates – Any document update, even for a single field, creates a new revision of the entire document in history, plus or minus the delta of the update. This means that a small update in a large document would still generate a large transaction delta. For example, adding 2 KB of data in an existing 100 KB document creates a new 102 KB revision in history. This adds up to at least 104 KB of total deltas in a transaction. (Again, this estimate doesn't include metadata or indexes.)
Deletes – Similar to updates, any delete transaction creates a new document revision in the history. However, the newly created
DELETErevision is smaller than the original document because it has null user data and only contains metadata.
Naming constraints
The following table describes naming constraints within Amazon QLDB.
| Ledger name |
|
| Journal stream name | |
| Table name |
|
