Service, account, and table quotas in Amazon DynamoDB

This section describes current quotas, formerly referred to as limits, within Amazon DynamoDB. Each quota applies on a per-Region basis unless otherwise specified.

Read/write capacity mode and throughput

You can switch tables from on-demand mode to provisioned capacity mode at any time. When you do multiple switches between capacity modes, the following conditions apply:

For more information about switching between read and write capacity modes, see Considerations when switching capacity modes in DynamoDB.

Capacity unit sizes (for provisioned tables)

One read capacity unit = one strongly consistent read per second, or two eventually consistent reads per second, for items up to 4 KB in size.

One write capacity unit = one write per second, for items up to 1 KB in size.

Transactional read requests require two read capacity units to perform one read per second for items up to 4 KB.

Transactional write requests require two write capacity units to perform one write per second for items up to 1 KB.

Request unit sizes (for on-demand tables)

One read request unit = one strongly consistent read per second, or two eventually consistent reads per second, for items up to 4 KB in size.

One write request unit = one write per second, for items up to 1 KB in size.

Transactional read requests require two read request units to perform one read per second for items up to 4 KB.

Transactional write requests require two write request units to perform one write per second for items up to 1 KB.

Throughput default quotas

AWS places some default quotas on the throughput that your account can provision and consume within a Region.

The account-level read throughput and account-level write throughput quotas apply at the account level. These account-level quotas apply to the sum of the provisioned throughput capacity for all your account’s tables and global secondary indexes in a given Region. All the account's available throughput can be provisioned for a single table or across multiple tables. These quotas only apply to tables using the provisioned capacity mode.

The table-level read throughput and table-level write throughput quotas apply differently to tables that use the provisioned capacity mode, and tables that use the on-demand capacity mode.

For provisioned capacity mode tables and GSIs, the quota is the maximum amount of read and write capacity units that can be provisioned for any table or any of its GSIs in the Region. The total of any individual table and all its GSIs must also remain below the account-level read and write throughput quota. This is in addition to the requirement that the total of all provisioned tables and their GSIs must remain below the account-level read and write throughput quota.

For on-demand capacity mode tables and GSIs, the table-level quota is the maximum read and write capacity units that are available for any table, or any individual GSI within that table. No account-level read and write throughput quotas are applied to tables in on-demand mode.

Following are the throughput quotas that apply on your account, by default.

You can use the Service Quotas console, the AWS API and the AWS CLI to request quota increases for the adjustable quotas when needed.

For your account-level throughput quotas, you can use the Service Quotas console, the AWS CloudWatch console, the AWS API and the AWS CLI to create CloudWatch alarms and be notified automatically when your current usage reaches a specified percentage of your applied quota values. Using CloudWatch you can also monitor your usage by looking at the AccountProvisionedReadCapacityUnits and AccountProvisionedWriteCapacityUnits AWS usage metrics. To learn more about usage metrics, see AWS usage metrics.

Increasing or decreasing throughput (for provisioned tables)

Increasing provisioned throughput

You can increase ReadCapacityUnits or WriteCapacityUnits as often as necessary, using the AWS Management Console or the UpdateTable operation. In a single call, you can increase the provisioned throughput for a table, for any global secondary indexes on that table, or for any combination of these. The new settings do not take effect until the UpdateTable operation is complete.

You can't exceed your per-account quotas when you add provisioned capacity, and DynamoDB doesn't allow you to increase provisioned capacity very rapidly. Aside from these restrictions, you can increase the provisioned capacity for your tables as high as you need. For more information about per-account quotas, see the preceding section, Throughput default quotas.

Decreasing provisioned throughput

For every table and global secondary index in an UpdateTable operation, you can decrease ReadCapacityUnits or WriteCapacityUnits (or both). The new settings don't take effect until the UpdateTable operation is complete.

There is a default quota on the number of provisioned capacity decreases you can perform on your DynamoDB table per day. A day is defined according to Universal Time Coordinated (UTC). On a given day, you can start by performing up to four decreases within one hour as long as you have not performed any other decreases yet during that day. Subsequently, you can perform one additional decrease per hour (once every 60 minutes). This effectively brings the maximum number of decreases in a day to 27 times.

You can use the Service Quotas console, the AWS API and the AWS CLI to request quota increases, when needed.

Reserved Capacity

AWS places a default quota on the amount of active reserved capacity that your account can purchase. The quota limit is a combination of reserved capacity for write capacity units (WCUs) and read capacity units (RCUs).

If you attempt to purchase more than 1,000,000 provisioned capacity units in a single purchase, you will receive an error for this service quota limit. If you have active reserved capacity and attempt to purchase additional reserved capacity that would result in more than 1,000,000 active provisioned capacity units, you will receive an error for this service quota limit.

If you need reserved capacity for more than 1,000,000 provisioned capacity units, you can request a quota increase by submitting a request to the support team.

Import quotas

DynamoDB Import from Amazon S3 can support up to 50 concurrent import jobs with a total import source object size of 15TB at a time in us-east-1, us-west-2, and eu-west-1 regions. In all other regions, up to 50 concurrent import tasks with a total size of 1TB is supported. Each import job can take up to 50,000 Amazon S3 objects in all regions. For more information on import and validation, see import format quotas and validation.

Contributor Insights

When you enable Customer Insights on your DynamoDB table, you're still subject to Contributor Insights rules limits. For more information, see CloudWatch service quotas.

Tables

Table size

There is no practical limit on a table's size. Tables are unconstrained in terms of the number of items or the number of bytes.

Maximum number of tables per account per region

For any AWS account, there is an initial quota of 2,500 tables per AWS Region.

If you need more than 2,500 tables for a single account, please reach out to your AWS account team to explore an increase up to a maximum of 10,000 tables. For more than 10,000, the recommended best practice is to setup multiple accounts, each of which can serve up to 10,000 tables.

You can use the Service Quotas console, the AWS API and the AWS CLI to view the default and applied quota values for the maximum number of tables for in your account, and to request quota increases, when needed. You can also request quota increases by cutting a ticket to AWS support

Using the Service Quotas console, the AWS API and the AWS CLI you can create CloudWatch alarms to get notified automatically when your current usage reaches a specified percentage of your current quota. Using CloudWatch you can also monitor your usage by looking at the TableCount AWS usage metrics. To learn more about usage metrics, see AWS usage metrics.

Global tables

AWS places some default quotas on the throughput you can provision or utilize when using global tables.

Transactional operations provide atomicity, consistency, isolation, and durability (ACID) guarantees only within the AWS Region where the write is made originally. Transactions are not supported across Regions in global tables. For example, suppose that you have a global table with replicas in the US East (Ohio) and US West (Oregon) Regions and you perform a TransactWriteItems operation in the US East (N. Virginia) Region. In this case, you might observe partially completed transactions in the US West (Oregon) Region as changes are replicated. Changes are replicated to other Regions only after they have been committed in the source Region.

Secondary indexes

Secondary indexes per table

You can define a maximum of 5 local secondary indexes.

There is a default quota of 20 global secondary indexes per table. You can use the Service Quotas console, the AWS API and the AWS CLI to check the global secondary indexes per table default and current quotas that apply for your account, and to request quota increases, when needed. You can also request quota increases by cutting a ticket to https://aws.amazon.com/support.

You can create or delete only one global secondary index per UpdateTable operation.

Projected Secondary Index attributes per table

You can project a total of up to 100 attributes into all of a table's local and global secondary indexes. This only applies to user-specified projected attributes.

In a CreateTable operation, if you specify a ProjectionType of INCLUDE, the total count of attributes specified in NonKeyAttributes, summed across all of the secondary indexes, must not exceed 100. If you project the same attribute name into two different indexes, this counts as two distinct attributes when determining the total.

This limit does not apply for secondary indexes with a ProjectionType of KEYS_ONLY or ALL.

Partition keys and sort keys

Partition key length

The minimum length of a partition key value is 1 byte. The maximum length is 2048 bytes.

Partition key values

There is no practical limit on the number of distinct partition key values, for tables or for secondary indexes.

Sort key length

The minimum length of a sort key value is 1 byte. The maximum length is 1024 bytes.

Sort key values

In general, there is no practical limit on the number of distinct sort key values per partition key value.

The exception is for tables with secondary indexes. An item collection is the set of items which have the same value of partition key attribute. In a global secondary index the item collection is independent of the base table (and can have a different partition key attribute), but in a local secondary index the indexed view is colocated in the same partition as the item in the table and shares the same partition key attribute. As a result of this locality, when a table has one or more LSIs, the item collection cannot be distributed to multiple partitions.

For a table with one or more LSIs, item collections cannot exceed 10GB in size. This includes all base table items and all projected LSI views which have the same value of the partition key attribute. 10GB is the maximum size of a partition. For more detailed information, see Item collection size limit.

Naming rules

Table names and Secondary Index names

Names for tables and secondary indexes must be at least 3 characters long, but no greater than 255 characters long. The following are the allowed characters:

Attribute names

In general, an attribute name must be at least one character long, but no greater than 64 KB long.

The following are the exceptions. These attribute names must be no greater than 255 characters long:

These attribute names must be encoded using UTF-8, and the total size of each name (after encoding) cannot exceed 255 bytes.

Data types

String

The length of a String is constrained by the maximum item size of 400 KB.

Strings are Unicode with UTF-8 binary encoding. Because UTF-8 is a variable width encoding, DynamoDB determines the length of a String using its UTF-8 bytes.

Number

A Number can have up to 38 digits of precision, and can be positive, negative, or zero.

DynamoDB uses JSON strings to represent Number data in requests and replies. For more information, see DynamoDB low-level API.

If number precision is important, you should pass numbers to DynamoDB using strings that you convert from a number type.

Binary

The length of a Binary is constrained by the maximum item size of 400 KB.

Applications that work with Binary attributes must encode the data in base64 format before sending it to DynamoDB. Upon receipt of the data, DynamoDB decodes it into an unsigned byte array and uses that as the length of the attribute.

Items

Item size

The maximum item size in DynamoDB is 400 KB, which includes both attribute name binary length (UTF-8 length) and attribute value lengths (again binary length). The attribute name counts towards the size limit.

For example, consider an item with two attributes: one attribute named "shirt-color" with value "R" and another attribute named "shirt-size" with value "M". The total size of that item is 23 bytes.

Item size for tables with Local Secondary Indexes

For each local secondary index on a table, there is a 400 KB limit on the total of the following:

Attributes

Attribute name-value pairs per item

The cumulative size of attributes per item must fit within the maximum DynamoDB item size (400 KB).

Number of values in list, map, or set

There is no limit on the number of values in a List, a Map, or a Set, as long as the item containing the values fits within the 400 KB item size limit.

Attribute values

Empty String and Binary attribute values are allowed, if the attribute is not used as a key attribute for a table or index. Empty String and Binary values are allowed inside Set, List, and Map types. An attribute value cannot be an an empty Set (String Set, Number Set, or Binary Set). However, empty Lists and Maps are allowed.

Nested attribute depth

DynamoDB supports nested attributes up to 32 levels deep.

Expression parameters

Expression parameters include ProjectionExpression, ConditionExpression, UpdateExpression, and FilterExpression.

Lengths

The maximum length of any expression string is 4 KB. For example, the size of the ConditionExpression a=b is 3 bytes.

The maximum length of any single expression attribute name or expression attribute value is 255 bytes. For example, #name is 5 bytes; :val is 4 bytes.

The maximum length of all substitution variables in an expression is 2 MB. This is the sum of the lengths of all ExpressionAttributeNames and ExpressionAttributeValues.

Operators and operands

The maximum number of operators or functions allowed in an UpdateExpression is 300. For example, the UpdateExpression SET a = :val1 + :val2 + :val3 contains two "+" operators.

The maximum number of operands for the IN comparator is 100.

Reserved words

DynamoDB does not prevent you from using names that conflict with reserved words. (For a complete list, see Reserved words in DynamoDB.)

However, if you use a reserved word in an expression parameter, you must also specify ExpressionAttributeNames. For more information, see Expression attribute names (aliases) in DynamoDB.

DynamoDB transactions

DynamoDB transactional API operations have the following constraints:

DynamoDB Streams

Simultaneous readers of a shard in DynamoDB Streams

For single-Region tables that are not global tables, you can design for up to two processes to read from the same DynamoDB Streams shard at the same time. Exceeding this limit can result in request throttling. For global tables, we recommend you limit the number of simultaneous readers to one to avoid request throttling.

Maximum write capacity for a table with DynamoDB Streams enabled

AWS places some default quotas on the write capacity for DynamoDB tables with DynamoDB Streams enabled. These default quotas are applicable only for tables in provisioned read/write capacity mode. The following are throughput quotas that apply to your account by default.

You can use the Service Quotas console, the AWS API and the AWS CLI to check the maximum write capacity for a table with DynamoDB Streams enabled default and current quotas that apply on your account, and to request quota increases, when needed. You can also request quota increases by cutting a ticket to AWS support.

DynamoDB Accelerator (DAX)

AWS Region availability

For a list of AWS Regions in which DAX is available, see DynamoDB Accelerator (DAX) in the AWS General Reference.

Nodes

A DAX cluster consists of exactly one primary node, and between zero and ten read replica nodes.

The total number of nodes (per AWS account) cannot exceed 50 in a single AWS Region.

Parameter groups

You can create up to 20 DAX parameter groups per Region.

Subnet groups

You can create up to 50 DAX subnet groups per Region.

Within a subnet group, you can define up to 20 subnets.

API-specific limits

DynamoDB encryption at rest

You can switch between an AWS owned key, an AWS managed key, and a customer managed key up to four times, anytime per 24-hour window, on a per table basis, starting from when the table was created. If there was no change in the past six hours, an additional change is allowed. This effectively brings the maximum number of changes in a day to eight (four changes in the first six hours, and one change for each of the subsequent six hour windows in a day).

You can switch encryption keys to use an AWS owned key as often as necessary, even if the above quota has been exhausted.

These are the quotas unless you request a higher amount. To request a service quota increase, see https://aws.amazon.com/support.

Table export to Amazon S3

Full export: up to 300 concurrent export tasks, or up to a total of 100TB from all in-flight table exports, can be exported. Both of these limits are checked before an export is queued.

Incremental export: up to 300 concurrent jobs, or 100TB of table size, in an export period window between 15 minutes minimum and 24 hours maximum, can be exported concurrently.

Backup and restore

When restoring through DynamoDB on-demand backup, you can execute up to 50 concurrent restores that total 50TB. When restoring through AWS Backup, you can execute up to 50 concurrent restores that total 25TB. For more information about backups, see Backup and restore for DynamoDB.