OpenSearch creates an image for uploaded data and data that is synchronized from data sources. If you modify the schema of an application or upload full data to the application, you must perform reindexing. The following scenarios trigger reindexing:
Scheduled reindexing: Full data is synchronized from a MaxCompute data source to an application every day.
Offline changes: If you modify the schema of an application or modify index or attribute fields, OpenSearch triggers reindexing.
Scheduled reindexing
After you create a scheduled reindexing task, OpenSearch performs reindexing once at the specified time every day.
1. Log on to the OpenSearch console. In the upper-left corner, select OpenSearch High-performance Search Edition. On the Instance Management page, find the application that you want to manage and click Details in the Action column.
2. Click Reindex.
3. Specify a time when the scheduled reindexing task is triggered. The minimum interval at which the scheduled reindexing task is triggered is 24 hours. This means that the scheduled reindexing task can be triggered once a day.
Note:
An application can have up to two versions, which are the online version and the offline version. If an application has two versions, the offline version will be automatically deleted in a scheduled reindexing task. The offline version must be deleted in a manual reindexing task.
When the scheduled reindexing task is complete, the created offline version is published to replace the online version. OpenSearch automatically deletes the replaced version within 8 to 16 hours after the version is replaced.
Reindexing procedure and progress
Reindexing is performed in the following procedure: 1. Import data. 2. Process the data. 3. Build indexes.
After data is synchronized from a data source, OpenSearch processes the data and delivers the data to the build service for index building. If full data is synchronized, OpenSearch performs reindexing on a regular basis. The time that is required for each reindexing is 30 minutes. Therefore, the reindexing of full data takes some time even though only a small number of documents are involved. The OpenSearch console displays the progress of reindexing based on the status of each step.
Usage notes
After you modify an application offline, OpenSearch generates an offline version of the application. In this case, the online version and the offline version exist at the same time on the application details page in the OpenSearch console.
If both the online version and the offline version of an application exist, only the online version provides search services. When you use an application to search for data by specifying the application name in an API operation, the online version is used.
If both the online version and the offline version of an application exist, the offline changes and reindexing features cannot be used. To resolve this problem, delete a version as required and publish the retained version.
After you delete an application, you cannot recover the application.