Understanding Amazon CloudSearch Limits - Amazon CloudSearch

Understanding Amazon CloudSearch Limits

This table shows naming and size restrictions within Amazon CloudSearch. You can submit a request if you need to increase the maximum number of partitions for a search domain. For information about increasing other limits such as the maximum number of search domains, contact Amazon CloudSearch.

The current Amazon CloudSearch limits are summarized in the following table.

Item Limit
Batch size The maximum batch size is 5 MB.
Data loading volume

You can load one document batch every 10 seconds (approximately 10,000 batches every 24 hours), with each batch size up to 5 MB.

Exceeding this limit significantly increases the latency of document updates and could result in throttling. To mitigate this risk, you can increase your update capacity by selecting a larger instance type. For more information, see Creating Document Batches.

Important

No matter which instance type you select, Amazon CloudSearch does not guarantee the ordering of documents received in the same second. For example, if you send three updates with a tenth of a second between them, the final update might not be the last one applied. Preserving update order is yet another reason to adhere to this limit.
Document size The maximum document size is 1 MB.
Document fields Documents can have no more than 200 fields.
Expressions

  • Up to 50 expressions can be configured for a domain.

  • The maximum size of an expression is 10240 bytes.

  • The maximum value that can be returned by an expression is max(int64_t).
Highlighting

  • The maximum number of occurrences of the search term(s) that can be highlighted is 5.

  • Highlights are only returned for the first 10 KB of data in a text field.
Index fields

  • Up to 200 index fields can be configured for a domain. A dynamic field counts as one index field, but typically matches multiple document fields. Dynamic fields can cause the total number of fields in your index to exceed 200. If you use dynamic fields, keep the number of index fields below 1,000 to avoid performance issues.

  • Up to 1000 values can be specified in a field.

  • Up to 20 sources can be specified for an array-type field.

  • The maximum size of a literal field is 4096 UTF-8 code points.

  • The maximum size of a default value for a field is 1 KB.

  • An int field can contain values from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807 (inclusive).

  • Individual terms within a text or text-array field are treated as stopwords if they exceed 256 characters.
Naming conventions

  • Domain Names: Allowed characters are a-z (lower-case letters), 0-9, and hyphen (-). Domain names must start with a letter or number and be at least 3 and no more than 28 characters long.

  • Field Names: Allowed characters are a-z (lower-case letters), 0-9, and _ (underscore). Field names must begin with a letter and be at least 1 and no more than 64 characters long. The name score is reserved and cannot be used as a field name.

  • Expression Names: Allowed characters are a-z (lower-case letters), 0-9, and _ (underscore). Expression names must begin with a letter and be at least 3 and no more than 64 characters long. The name score is reserved and cannot be used as an expression name.

  • Document IDs: A document ID (_id) can contain any letter or number and the following characters: _ - = # ; : / ? @ &. Document IDs must be at least 1 and no more than 128 characters long.

Policy document size The maximum size of an Amazon CloudSearch policy document is 100 KB.
Region restriction The ap-northeast-2 region supports only m4 instance types.
_score A document's text relevance score is a positive floating point value.
Search domains Each AWS account can create up to 100 search domains.
Search partitions

A search index can be split across a maximum of 10 partitions. You can submit a request if you need to increase this limit.

To avoid search query failures, Amazon CloudSearch domains can grow beyond this maximum partition limit, but new document additions are rejected. If you encounter this scenario, delete documents and trigger the IndexDocuments API. Alternately, request a limit increase.

You can monitor the Amazon CloudWatch IndexUtilization and Partitions metrics to take action before exceeding the maximum partition limit.
Search replicas

Each search partition can have up to 5 replicas.

Note

Enabling Multi-AZ doubles the number of replicas.
Search requests

  • compound queries: Can contain a maximum of 1024 clauses.

  • GET requests: The maximum size of a search request submitted as an HTTP GET request is 8190 bytes.

  • facet parameter: The maximum number of facet values you can return is 10,000.

  • size parameter: Can contain values in the range 0 - 10000. The sum of the size and start parameters cannot exceed 10,000. If you need to page through more than 10,000 hits, use a cursor.

  • sort parameter: Can contain up to 10 int fields and expressions.

  • start parameter: Can contain values in the range 0 - 10000. The sum of the size and start parameters cannot exceed 10,000. If you need to page through more than 10,000 hits, use a cursor.
Suggesters

  • You can define a maximum of 10 suggesters for a domain.

  • Only the first 512 bytes of a text field are used to generate suggestions.

  • The scores computed from a suggester's SortExpression are rounded to the nearest integer, with a floor of 0 and a ceiling of 2^31-1.
Synonym dictionary size The maximum size of a Amazon CloudSearch synonym dictionary is 100 KB.