Why would you use a secondary index on a DynamoDB table?
A table can have multiple secondary indexes, which give your applications access to many different query patterns. DynamoDB copies these attributes into the index, along with the primary key attributes from the base table. You can then query or scan the index just as you would query or scan a table.
How many secondary indexes are allowed in DynamoDB?
Each table in DynamoDB can have up to 20 global secondary indexes (default quota) and 5 local secondary indexes.
How can I make DynamoDB query faster?
You can increase your DynamoDB throughput by several times, by parallelizing reads/writes over multiple partitions. Use DynamoDB as an attribute store rather than as a document store. This will not only reduce the read/write costs but also improve the performance of your operations considerably.
Why do we need global secondary index?
If you need to access most of the non-key attributes on a frequent basis, you can project these attributes—or even the entire base table— into a global secondary index. This gives you maximum flexibility. However, your storage cost would increase, or even double.
Can you have 10 local secondary indexes on a table?
The data in a local secondary index is organized by the same partition key as the base table, but with a different sort key. This lets you access data items efficiently across this different dimension. For greater query or scan flexibility, you can create up to five local secondary indexes per table.
When would it be useful to maintain a secondary index?
One of the more common uses for a Unique Secondary Index arises with the need to maintain uniqueness on a column or columns that are NOT the primary index. The primary index is NOT a primary key.
How do secondary indexes work?
A secondary index, put simply, is a way to efficiently access records in a database (the primary) by means of some piece of information other than the usual (primary) key. Secondary indexes can be created manually by the application; there is no disadvantage, other than complexity, to doing so. …
How fast are DynamoDB reads?
Key metrics:
| Name | Description |
|---|---|
| ReadThrottleEvents | Number of read events which exceeded your provisioned read throughput in the selected time period (sum). |
| WriteThrottleEvents | Number of write events which exceeded your provisioned write throughput in the selected time period (sum). |
Can DynamoDB secondary index be null?
It appears that DynamoDB secondary indexes can’t be null and require a range key, so despite the similar name to Riak’s secondary indexes, make this appear quite a different beast.
How does DynamoDB define global secondary index?
Open the DynamoDB console at .
- In the navigation pane on the left side of the console, choose Tables.
- Choose the Music table from the table list.
- Choose the Indexes tab for the Music table.
- Choose Create index.
- For the Partition key, enter AlbumTitle .
Is DynamoDB eventually consistent?
The data is eventually consistent across all storage locations, usually within one second or less. DynamoDB supports eventually consistent and strongly consistent reads. When you read data from a DynamoDB table, the response might not reflect the results of a recently completed write operation.
What types of secondary indexes does DynamoDB support?
Amazon DynamoDB supports two types of secondary indexes: Global secondary index— An index with a partition key and a sort key that can be different from those on the base table. A global secondary index is considered “global” because queries on the index can span all of the data in the base table, across all partitions.
What is the DynamoDB primary key model?
Whether you’re an experienced Amazon DynamoDB user or just starting out, you’re probably familiar with the basics of the DynamoDB primary key model. This key model provides consistent single-digit millisecond performance at any scale.
What is the size of a DynamoDB schema?
The following table shows the schema of the DynamoDB table. The size of each item in the table is 100 KB, but to display the preview of the product on the website, the company needs only a few attributes — ProductName, ProductDescription, and Price. These add up to less than 4 KB.
What is an item collection in DynamoDB?
An item collection is all the items in a table and its local secondary indexes that have the same partition key. No item collection can exceed 10 GB, so it’s possible to run out of space for a particular partition key value. When you add or update a table item, DynamoDB updates all local secondary indexes that are affected.
