Class DynamoDB

This operation allows you to perform batch reads or writes on data stored in DynamoDB, using PartiQL. Each read statement in a BatchExecuteStatement must specify an equality condition on all key attributes. This enforces that each SELECT statement in a batch returns at most a single item.

The BatchGetItem operation returns the attributes of one or more items from one or more tables. You identify requested items by primary key.

A single operation can retrieve up to 16 MB of data, which can contain as many as 100 items. BatchGetItem returns a partial result if the response size limit is exceeded, the table's provisioned throughput is exceeded, or an internal processing failure occurs. If a partial result is returned, the operation returns a value for UnprocessedKeys. You can use this value to retry the operation starting with the next item to get.

For example, if you ask to retrieve 100 items, but each individual item is 300 KB in size, the system returns 52 items (so as not to exceed the 16 MB limit). It also returns an appropriate UnprocessedKeys value so you can get the next page of results. If desired, your application can include its own logic to assemble the pages of results into one dataset.

If none of the items can be processed due to insufficient provisioned throughput on all of the tables in the request, then BatchGetItem returns a ProvisionedThroughputExceededException. If at least one of the items is successfully processed, then BatchGetItem completes successfully, while returning the keys of the unread items in UnprocessedKeys.

By default, BatchGetItem performs eventually consistent reads on every table in the request. If you want strongly consistent reads instead, you can set ConsistentRead to true for any or all tables.

In order to minimize response latency, BatchGetItem retrieves items in parallel.

When designing your application, keep in mind that DynamoDB does not return items in any particular order. To help parse the response by item, include the primary key values for the items in your request in the ProjectionExpression parameter.

If a requested item does not exist, it is not returned in the result. Requests for nonexistent items consume the minimum read capacity units according to the type of read. For more information, see Working with Tables in the Amazon DynamoDB Developer Guide.

The BatchWriteItem operation puts or deletes multiple items in one or more tables. A single call to BatchWriteItem can transmit up to 16MB of data over the network, consisting of up to 25 item put or delete operations. While individual items can be up to 400 KB once stored, it's important to note that an item's representation might be greater than 400KB while being sent in DynamoDB's JSON format for the API call. For more details on this distinction, see Naming Rules and Data Types.

The individual PutItem and DeleteItem operations specified in BatchWriteItem are atomic; however BatchWriteItem as a whole is not. If any requested operations fail because the table's provisioned throughput is exceeded or an internal processing failure occurs, the failed operations are returned in the UnprocessedItems response parameter. You can investigate and optionally resend the requests. Typically, you would call BatchWriteItem in a loop. Each iteration would check for unprocessed items and submit a new BatchWriteItem request with those unprocessed items until all items have been processed.

If none of the items can be processed due to insufficient provisioned throughput on all of the tables in the request, then BatchWriteItem returns a ProvisionedThroughputExceededException.

With BatchWriteItem, you can efficiently write or delete large amounts of data, such as from Amazon EMR, or copy data from another database into DynamoDB. In order to improve performance with these large-scale operations, BatchWriteItem does not behave in the same way as individual PutItem and DeleteItem calls would. For example, you cannot specify conditions on individual put and delete requests, and BatchWriteItem does not return deleted items in the response.

If you use a programming language that supports concurrency, you can use threads to write items in parallel. Your application must include the necessary logic to manage the threads. With languages that don't support threading, you must update or delete the specified items one at a time. In both situations, BatchWriteItem performs the specified put and delete operations in parallel, giving you the power of the thread pool approach without having to introduce complexity into your application.

Parallel processing reduces latency, but each specified put and delete request consumes the same number of write capacity units whether it is processed in parallel or not. Delete operations on nonexistent items consume one write capacity unit.

If one or more of the following is true, DynamoDB rejects the entire batch write operation:

• One or more tables specified in the BatchWriteItem request does not exist.

• Primary key attributes specified on an item in the request do not match those in the corresponding table's primary key schema.

• You try to perform multiple operations on the same item in the same BatchWriteItem request. For example, you cannot put and delete the same item in the same BatchWriteItem request.

• Your request contains at least two items with identical hash and range keys (which essentially is two put operations).

• There are more than 25 requests in the batch.

• Any individual item in a batch exceeds 400 KB.

• The total request size exceeds 16 MB.

Creates a backup for an existing table.

Each time you create an on-demand backup, the entire table data is backed up. There is no limit to the number of on-demand backups that can be taken.

When you create an on-demand backup, a time marker of the request is cataloged, and the backup is created asynchronously, by applying all changes until the time of the request to the last full table snapshot. Backup requests are processed instantaneously and become available for restore within minutes.

You can call CreateBackup at a maximum rate of 50 times per second.

All backups in DynamoDB work without consuming any provisioned throughput on the table.

If you submit a backup request on 2018-12-14 at 14:25:00, the backup is guaranteed to contain all data committed to the table up to 14:24:00, and data committed after 14:26:00 will not be. The backup might contain data modifications made between 14:24:00 and 14:26:00. On-demand backup does not support causal consistency.

Along with data, the following are also included on the backups:

• Global secondary indexes (GSIs)

• Local secondary indexes (LSIs)

• Streams

• Provisioned read and write capacity

Creates a global table from an existing table. A global table creates a replication relationship between two or more DynamoDB tables with the same table name in the provided Regions.

If you want to add a new replica table to a global table, each of the following conditions must be true:

• The table must have the same primary key as all of the other replicas.

• The table must have the same name as all of the other replicas.

• The table must have DynamoDB Streams enabled, with the stream containing both the new and the old images of the item.

• None of the replica tables in the global table can contain any data.

If global secondary indexes are specified, then the following conditions must also be met:

• The global secondary indexes must have the same name.

• The global secondary indexes must have the same hash key and sort key (if present).

If local secondary indexes are specified, then the following conditions must also be met:

• The local secondary indexes must have the same name.

• The local secondary indexes must have the same hash key and sort key (if present).

The CreateTable operation adds a new table to your account. In an Amazon Web Services account, table names must be unique within each Region. That is, you can have two tables with same name if you create the tables in different Regions.

CreateTable is an asynchronous operation. Upon receiving a CreateTable request, DynamoDB immediately returns a response with a TableStatus of CREATING. After the table is created, DynamoDB sets the TableStatus to ACTIVE. You can perform read and write operations only on an ACTIVE table.

You can optionally define secondary indexes on the new table, as part of the CreateTable operation. If you want to create multiple tables with secondary indexes on them, you must create the tables sequentially. Only one table with secondary indexes can be in the CREATING state at any given time.

You can use the DescribeTable action to check the table status.

Deletes an existing backup of a table.

You can call DeleteBackup at a maximum rate of 10 times per second.

Deletes a single item in a table by primary key. You can perform a conditional delete operation that deletes the item if it exists, or if it has an expected attribute value.

In addition to deleting an item, you can also return the item's attribute values in the same operation, using the ReturnValues parameter.

Unless you specify conditions, the DeleteItem is an idempotent operation; running it multiple times on the same item or attribute does not result in an error response.

Conditional deletes are useful for deleting items only if specific conditions are met. If those conditions are met, DynamoDB performs the delete. Otherwise, the item is not deleted.

The DeleteTable operation deletes a table and all of its items. After a DeleteTable request, the specified table is in the DELETING state until DynamoDB completes the deletion. If the table is in the ACTIVE state, you can delete it. If a table is in CREATING or UPDATING states, then DynamoDB returns a ResourceInUseException. If the specified table does not exist, DynamoDB returns a ResourceNotFoundException. If table is already in the DELETING state, no error is returned.

When you delete a table, any indexes on that table are also deleted.

If you have DynamoDB Streams enabled on the table, then the corresponding stream on that table goes into the DISABLED state, and the stream is automatically deleted after 24 hours.

Use the DescribeTable action to check the status of the table.

Describes an existing backup of a table.

You can call DescribeBackup at a maximum rate of 10 times per second.

Checks the status of continuous backups and point in time recovery on the specified table. Continuous backups are ENABLED on all tables at table creation. If point in time recovery is enabled, PointInTimeRecoveryStatus will be set to ENABLED.

After continuous backups and point in time recovery are enabled, you can restore to any point in time within EarliestRestorableDateTime and LatestRestorableDateTime.

LatestRestorableDateTime is typically 5 minutes before the current time. You can restore your table to any point in time during the last 35 days.

You can call DescribeContinuousBackups at a maximum rate of 10 times per second.

Returns information about contributor insights for a given table or global secondary index.

Returns the regional endpoint information. This action must be included in your VPC endpoint policies, or access to the DescribeEndpoints API will be denied. For more information on policy permissions, please see Internetwork traffic privacy.

Describes an existing table export.

Returns information about the specified global table.

Describes Region-specific settings for a global table.

Represents the properties of the import.

Returns information about the status of Kinesis streaming.

Returns the current provisioned-capacity quotas for your Amazon Web Services account in a Region, both for the Region as a whole and for any one DynamoDB table that you create there.

When you establish an Amazon Web Services account, the account has initial quotas on the maximum read capacity units and write capacity units that you can provision across all of your DynamoDB tables in a given Region. Also, there are per-table quotas that apply when you create a table there. For more information, see Service, Account, and Table Quotas page in the Amazon DynamoDB Developer Guide.

Although you can increase these quotas by filing a case at Amazon Web Services Support Center, obtaining the increase is not instantaneous. The DescribeLimits action lets you write code to compare the capacity you are currently using to those quotas imposed by your account so that you have enough time to apply for an increase before you hit a quota.

For example, you could use one of the Amazon Web Services SDKs to do the following:

1. Call DescribeLimits for a particular Region to obtain your current account quotas on provisioned capacity there.

2. Create a variable to hold the aggregate read capacity units provisioned for all your tables in that Region, and one to hold the aggregate write capacity units. Zero them both.

3. Call ListTables to obtain a list of all your DynamoDB tables.

4. For each table name listed by ListTables, do the following:

   • Call DescribeTable with the table name.

   • Use the data returned by DescribeTable to add the read capacity units and write capacity units provisioned for the table itself to your variables.

   • If the table has one or more global secondary indexes (GSIs), loop over these GSIs and add their provisioned capacity values to your variables as well.

5. Report the account quotas for that Region returned by DescribeLimits, along with the total current provisioned capacity levels you have calculated.

This will let you see whether you are getting close to your account-level quotas.

The per-table quotas apply only when you are creating a new table. They restrict the sum of the provisioned capacity of the new table itself and all its global secondary indexes.

For existing tables and their GSIs, DynamoDB doesn't let you increase provisioned capacity extremely rapidly, but the only quota that applies is that the aggregate provisioned capacity over all your tables and GSIs cannot exceed either of the per-account quotas.

The DescribeLimits Request element has no content.

Returns information about the table, including the current status of the table, when it was created, the primary key schema, and any indexes on the table.

Describes auto scaling settings across replicas of the global table at once.

Gives a description of the Time to Live (TTL) status on the specified table.

Stops replication from the DynamoDB table to the Kinesis data stream. This is done without deleting either of the resources.

Starts table data replication to the specified Kinesis data stream at a timestamp chosen during the enable workflow. If this operation doesn't return results immediately, use DescribeKinesisStreamingDestination to check if streaming to the Kinesis data stream is ACTIVE.

This operation allows you to perform reads and singleton writes on data stored in DynamoDB, using PartiQL.

For PartiQL reads (SELECT statement), if the total number of processed items exceeds the maximum dataset size limit of 1 MB, the read stops and results are returned to the user as a LastEvaluatedKey value to continue the read in a subsequent operation. If the filter criteria in WHERE clause does not match any data, the read will return an empty result set.

A single SELECT statement response can return up to the maximum number of items (if using the Limit parameter) or a maximum of 1 MB of data (and then apply any filtering to the results using WHERE clause). If LastEvaluatedKey is present in the response, you need to paginate the result set. If NextToken is present, you need to paginate the result set and include NextToken.

This operation allows you to perform transactional reads or writes on data stored in DynamoDB, using PartiQL.

Exports table data to an S3 bucket. The table must have point in time recovery enabled, and you can export data from any time within the point in time recovery window.

The GetItem operation returns a set of attributes for the item with the given primary key. If there is no matching item, GetItem does not return any data and there will be no Item element in the response.

GetItem provides an eventually consistent read by default. If your application requires a strongly consistent read, set ConsistentRead to true. Although a strongly consistent read might take more time than an eventually consistent read, it always returns the last updated value.

Imports table data from an S3 bucket.

List backups associated with an Amazon Web Services account. To list backups for a given table, specify TableName. ListBackups returns a paginated list of results with at most 1 MB worth of items in a page. You can also specify a maximum number of entries to be returned in a page.

In the request, start time is inclusive, but end time is exclusive. Note that these boundaries are for the time at which the original backup was requested.

You can call ListBackups a maximum of five times per second.

Returns a list of ContributorInsightsSummary for a table and all its global secondary indexes.

Lists completed exports within the past 90 days.

Lists all global tables that have a replica in the specified Region.

Lists completed imports within the past 90 days.

Returns an array of table names associated with the current account and endpoint. The output from ListTables is paginated, with each page returning a maximum of 100 table names.

List all tags on an Amazon DynamoDB resource. You can call ListTagsOfResource up to 10 times per second, per account.

For an overview on tagging DynamoDB resources, see Tagging for DynamoDB in the Amazon DynamoDB Developer Guide.

Creates a new item, or replaces an old item with a new item. If an item that has the same primary key as the new item already exists in the specified table, the new item completely replaces the existing item. You can perform a conditional put operation (add a new item if one with the specified primary key doesn't exist), or replace an existing item if it has certain attribute values. You can return the item's attribute values in the same operation, using the ReturnValues parameter.

When you add an item, the primary key attributes are the only required attributes.

Empty String and Binary attribute values are allowed. Attribute values of type String and Binary must have a length greater than zero if the attribute is used as a key attribute for a table or index. Set type attributes cannot be empty.

Invalid Requests with empty values will be rejected with a ValidationException exception.

For more information about PutItem, see Working with Items in the Amazon DynamoDB Developer Guide.