OpenSearch:Summary indexes

Introduction

A summary index can store information that corresponds to a document. OpenSearch Retrieval Engine Edition can use the docID to obtain the location in which the information is stored. This way, OpenSearch Retrieval Engine Edition can provide you with the storage location of the information. The schema of a summary index is similar to the schema of a forward index. The features of the indexes are different.

Sample code for configuring a summary index

"summarys":
{
	"summary_fields":["id", "company_id", "subject", "cat_id"],
	"compress":false,
  "parameter" : {
      "compress_type" : "uniq|equal",    
      "file_compress" : "simple_compress1"
  } 
}

• The summary_fields parameter specifies the fields that you want to store in your summary index. You can specify fields of all data types for this parameter.

• The compress parameter specifies whether to compress your summary index by using zlib. Valid values: true and false. A value of true indicates that your summary index is compressed, whereas a value of false indicates that your summary index is not compressed. Default value: false.

• When you specify a field of the TIMESTAMP data type for a summary index, the field is stored as an attribute. This way, the time format is processed by the system in a centralized manner if the default time zone is used.

• You can use the parameter field to configure specific parameters. OpenSearch Retrieval Engine Edition V3.9.1 and later support the parameter field. The following parameters are supported:

• The compress_type parameter specifies the encoding method. For information about uniq and equal, see Forward index compression.

• You can specify the file_compress parameter to compress a file. You must specify the alias of a compressed file for the file_compress parameter after you specify the alias in the file named schema.json. The file_compress parameter provides better performance for compression than the compress parameter. We recommend that you set the value of the compress parameter to false and configure the file_compress parameter to provide better performance for compression.