@aws-sdk/client-dynamodb
Version:
AWS SDK for JavaScript Dynamodb Client for Node.js, Browser and React Native
92 lines • 5.89 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.BatchGetItemCommand = void 0;
const models_0_1 = require("../models/models_0");
const Aws_json1_0_1 = require("../protocols/Aws_json1_0");
const middleware_serde_1 = require("@aws-sdk/middleware-serde");
const smithy_client_1 = require("@aws-sdk/smithy-client");
/**
* <p>The <code>BatchGetItem</code> operation returns the attributes of one or more items from one or
* more tables. You identify requested items by primary key.</p>
* <p>A single operation can retrieve up to 16 MB of data, which can contain as many as 100
* items. <code>BatchGetItem</code> 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
* <code>UnprocessedKeys</code>. You can use this value to retry the operation starting
* with the next item to get.</p>
* <important>
* <p>If you request more than 100 items, <code>BatchGetItem</code> returns a
* <code>ValidationException</code> with the message "Too many items requested for
* the BatchGetItem call."</p>
* </important>
* <p>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 <code>UnprocessedKeys</code> 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.</p>
* <p>If <i>none</i> of the items can be processed due to insufficient
* provisioned throughput on all of the tables in the request, then
* <code>BatchGetItem</code> returns a
* <code>ProvisionedThroughputExceededException</code>. If <i>at least
* one</i> of the items is successfully processed, then
* <code>BatchGetItem</code> completes successfully, while returning the keys of the
* unread items in <code>UnprocessedKeys</code>.</p>
* <important>
* <p>If DynamoDB returns any unprocessed items, you should retry the batch operation on those
* items. However, <i>we strongly recommend that you use an exponential backoff algorithm</i>.
* If you retry the batch operation immediately, the underlying read or write requests can
* still fail due to throttling on the individual tables. If you delay the batch operation
* using exponential backoff, the individual requests in the batch are much more likely to
* succeed.</p>
* <p>For more information, see <a href="https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/ErrorHandling.html#BatchOperations">Batch
* Operations and Error Handling</a> in the <i>Amazon DynamoDB Developer Guide</i>.</p>
* </important>
* <p>By default, <code>BatchGetItem</code> performs eventually consistent reads on every table in the
* request. If you want strongly consistent reads instead, you can set <code>ConsistentRead</code> to
* <code>true</code> for any or all tables.</p>
* <p>In order to minimize response latency, <code>BatchGetItem</code> retrieves items in parallel.</p>
* <p>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 <code>ProjectionExpression</code> parameter.</p>
* <p>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 <a href="https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/WorkingWithTables.html#CapacityUnitCalculations">Working with Tables</a> in the <i>Amazon DynamoDB Developer
* Guide</i>.</p>
*/
class BatchGetItemCommand extends smithy_client_1.Command {
// Start section: command_properties
// End section: command_properties
constructor(input) {
// Start section: command_constructor
super();
this.input = input;
// End section: command_constructor
}
/**
* @internal
*/
resolveMiddleware(clientStack, configuration, options) {
this.middlewareStack.use(middleware_serde_1.getSerdePlugin(configuration, this.serialize, this.deserialize));
const stack = clientStack.concat(this.middlewareStack);
const { logger } = configuration;
const clientName = "DynamoDBClient";
const commandName = "BatchGetItemCommand";
const handlerExecutionContext = {
logger,
clientName,
commandName,
inputFilterSensitiveLog: models_0_1.BatchGetItemInput.filterSensitiveLog,
outputFilterSensitiveLog: models_0_1.BatchGetItemOutput.filterSensitiveLog,
};
const { requestHandler } = configuration;
return stack.resolve((request) => requestHandler.handle(request.request, options || {}), handlerExecutionContext);
}
serialize(input, context) {
return Aws_json1_0_1.serializeAws_json1_0BatchGetItemCommand(input, context);
}
deserialize(output, context) {
return Aws_json1_0_1.deserializeAws_json1_0BatchGetItemCommand(output, context);
}
}
exports.BatchGetItemCommand = BatchGetItemCommand;
//# sourceMappingURL=BatchGetItemCommand.js.map