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.

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.

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 write up to 16 MB of data, which can comprise as many as 25 put or delete requests. Individual items to be written can be as large as 400 KB.

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.

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.

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.

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

• 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 AWS 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.

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.

Returns information about the specified global table.

Describes Region-specific settings for a global table.

Returns the current provisioned-capacity limits for your AWS 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 AWS account, the account has initial limits 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 limits that apply when you create a table there. For more information, see Limits page in the Amazon DynamoDB Developer Guide.

Although you can increase these limits by filing a case at AWS 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 limits imposed by your account so that you have enough time to apply for an increase before you hit a limit.

For example, you could use one of the AWS SDKs to do the following:

1. Call `DescribeLimits` for a particular Region to obtain your current account limits 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 limits for that Region returned by `DescribeLimits`, along with the total current provisioned capacity levels you have calculated.

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.

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.

List backups associated with an AWS 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 limit for the 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 limits 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 all global tables that have a replica in the specified Region.

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.

The Query operation finds items based on primary key values. You can query any table or secondary index that has a composite primary key (a partition key and a sort key).

Use the KeyConditionExpression parameter to provide a specific value for the partition key. The Query operation will return all of the items from the table or index with that partition key value. You can optionally narrow the scope of the Query operation by specifying a sort key value and a comparison operator in KeyConditionExpression. To further refine the Query results, you can optionally provide a FilterExpression. A FilterExpression determines which items within the results should be returned to you. All of the other results are discarded.

A Query operation always returns a result set. If no matching items are found, the result set will be empty. Queries that do not return results consume the minimum number of read capacity units for that type of read operation.

data type of the sort key is Number, the results are returned in numeric order; otherwise, the results are returned in order of UTF-8 bytes. By default, the sort order is ascending. To reverse the order, set the ScanIndexForward parameter to false.

A single Query operation will read up to the maximum number of items set (if using the Limit parameter) or a maximum of 1 MB of data and then apply any filtering to the results using FilterExpression. If LastEvaluatedKey is present in the response, you will need to paginate the result set. For more information, see Paginating the Results in the Amazon DynamoDB Developer Guide.

FilterExpression is applied after a Query finishes, but before the results are returned. A FilterExpression cannot contain partition key or sort key attributes. You need to specify those attributes in the KeyConditionExpression.

secondary index. For a query on a table or on a local secondary index, you can set the ConsistentRead parameter to true and obtain a strongly consistent result. Global secondary indexes support eventually consistent reads only, so do not specify ConsistentRead when querying a global secondary index.

Creates a new table from an existing backup. Any number of users can execute up to 4 concurrent restores (any type of restore) in a given account.

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

You must manually set up the following on the restored table:

• Auto scaling policies
• IAM policies
• Amazon CloudWatch metrics and alarms
• Tags
• Stream settings
• Time to Live (TTL) settings

Restores the specified table to the specified point in time within EarliestRestorableDateTime and LatestRestorableDateTime. You can restore your table to any point in time during the last 35 days. Any number of users can execute up to 4 concurrent restores (any type of restore) in a given account.

When you restore using point in time recovery, DynamoDB restores your table data to the state based on the selected date and time (day:hour:minute:second) to a new table.

Along with data, the following are also included on the new restored table using point in time recovery:

• Global secondary indexes (GSIs)
• Local secondary indexes (LSIs)
• Provisioned read and write capacity
• Encryption settings All these settings come from the current settings of the source table at the time of restore.

• Auto scaling policies
• IAM policies
• Amazon CloudWatch metrics and alarms
• Tags
• Stream settings
• Time to Live (TTL) settings
• Point in time recovery settings

The Scan operation returns one or more items and item attributes by accessing every item in a table or a secondary index. To have DynamoDB return fewer items, you can provide a FilterExpression operation.

If the total number of scanned items exceeds the maximum dataset size limit of 1 MB, the scan stops and results are returned to the user as a LastEvaluatedKey value to continue the scan in a subsequent operation. The results also include the number of items exceeding the limit. A scan can result in no table data meeting the filter criteria.

A single Scan operation reads up to the maximum number of items set (if using the Limit parameter) or a maximum of 1 MB of data and then apply any filtering to the results using FilterExpression. If LastEvaluatedKey is present in the response, you need to paginate the result set. For more information, see Paginating the Results in the Amazon DynamoDB Developer Guide.

Scan operations proceed sequentially; however, for faster performance on a large table or secondary index, applications can request a parallel Scan operation by providing the Segment and TotalSegments parameters. For more information, see Parallel Scan in the Amazon DynamoDB Developer Guide.

Scan uses eventually consistent reads when accessing the data in a table; therefore, the result set might not include the changes to data in the table immediately before the operation began. If you need a consistent copy of the data, as of the time that the Scan begins, you can set the ConsistentRead parameter to true.

Associate a set of tags with an Amazon DynamoDB resource. You can then activate these user-defined tags so that they appear on the Billing and Cost Management console for cost allocation tracking. You can call TagResource up to five times per second, per account.

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

TransactGetItems is a synchronous operation that atomically retrieves multiple items from one or more tables (but not from indexes) in a single account and Region. A TransactGetItems call can contain up to 25 TransactGetItem objects, each of which contains a Get structure that specifies an item to retrieve from a table in the account and Region. A call to TransactGetItems cannot retrieve items from tables in more than one AWS account or Region. The aggregate size of the items in the transaction cannot exceed 4 MB.

DynamoDB rejects the entire TransactGetItems request if any of the following is true:

• A conflicting operation is in the process of updating an item to be read.
• There is insufficient provisioned capacity for the transaction to be completed.
• There is a user error, such as an invalid data format.
• The aggregate size of the items in the transaction cannot exceed 4 MB.

TransactWriteItems is a synchronous write operation that groups up to 25 action requests. These actions can target items in different tables, but not in different AWS accounts or Regions, and no two actions can target the same item. For example, you cannot both ConditionCheck and Update the same item. The aggregate size of the items in the transaction cannot exceed 4 MB.

The actions are completed atomically so that either all of them succeed, or all of them fail. They are defined by the following objects:

• `Put`  —   Initiates a `PutItem` operation to write a new item. This structure specifies the primary key of the item to be written, the name of the table to write it in, an optional condition expression that must be satisfied for the write to succeed, a list of the item's attributes, and a field indicating whether to retrieve the item's attributes if the condition is not met.
• `Update`  —   Initiates an `UpdateItem` operation to update an existing item. This structure specifies the primary key of the item to be updated, the name of the table where it resides, an optional condition expression that must be satisfied for the update to succeed, an expression that defines one or more attributes to be updated, and a field indicating whether to retrieve the item's attributes if the condition is not met.
• `Delete`  —   Initiates a `DeleteItem` operation to delete an existing item. This structure specifies the primary key of the item to be deleted, the name of the table where it resides, an optional condition expression that must be satisfied for the deletion to succeed, and a field indicating whether to retrieve the item's attributes if the condition is not met.
• `ConditionCheck`  —   Applies a condition to an item that is not being modified by the transaction. This structure specifies the primary key of the item to be checked, the name of the table where it resides, a condition expression that must be satisfied for the transaction to succeed, and a field indicating whether to retrieve the item's attributes if the condition is not met.

• A condition in one of the condition expressions is not met.
• An ongoing operation is in the process of updating the same item.
• There is insufficient provisioned capacity for the transaction to be completed.
• An item size becomes too large (bigger than 400 KB), a local secondary index (LSI) becomes too large, or a similar validation error occurs because of changes made by the transaction.
• The aggregate size of the items in the transaction exceeds 4 MB.
• There is a user error, such as an invalid data format.

Removes the association of tags from an Amazon DynamoDB resource. You can call UntagResource up to five times per second, per account.

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

UpdateContinuousBackups enables or disables point in time recovery for the specified table. A successful UpdateContinuousBackups call returns the current ContinuousBackupsDescription. Continuous backups are ENABLED on all tables at table creation. If point in time recovery is enabled, PointInTimeRecoveryStatus will be set to ENABLED.

Once 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.

Updates the status for contributor insights for a specific table or index.

Adds or removes replicas in the specified global table. The global table must already exist to be able to use this operation. Any replica to be added must be empty, have the same name as the global table, have the same key schema, have DynamoDB Streams enabled, and have the same provisioned and maximum write capacity units.

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).
• The global secondary indexes must have the same provisioned and maximum write capacity units.

Updates settings for a global table.

Edits an existing item's attributes, or adds a new item to the table if it does not already exist. You can put, delete, or add attribute values. You can also perform a conditional update on an existing item (insert a new attribute name-value pair if it doesn't exist, or replace an existing name-value pair if it has certain expected attribute values).

You can also return the item's attribute values in the same UpdateItem operation using the ReturnValues parameter.

Modifies the provisioned throughput settings, global secondary indexes, or DynamoDB Streams settings for a given table.

You can only perform one of the following operations at once:

• Modify the provisioned throughput settings of the table.
• Enable or disable DynamoDB Streams on the table.
• Remove a global secondary index from the table.
• Create a new global secondary index on the table. After the index begins backfilling, you can use `UpdateTable` to perform other operations.

Updates auto scaling settings on your global tables at once.

The UpdateTimeToLive method enables or disables Time to Live (TTL) for the specified table. A successful UpdateTimeToLive call returns the current TimeToLiveSpecification. It can take up to one hour for the change to fully process. Any additional UpdateTimeToLive calls for the same table during this one hour duration result in a ValidationException.

TTL compares the current time in epoch time format to the time stored in the TTL attribute of an item. If the epoch time value stored in the attribute is less than the current time, the item is marked as expired and subsequently deleted.

availability of throughput for other data operations.

secondary index and global secondary index immediately in the same eventually consistent way as a standard delete operation.

For more information, see Time To Live in the Amazon DynamoDB Developer Guide.