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Short Description

Waiting for the page number needed to continue a parallel B-tree scan to become available.

Additional Information

An Inter Process Communication (IPC) wait. A parallel scan of a B-Tree index is in progress and a given page is being waited on to be able to continue the scan.

How to reduce this wait

There are references to a bug in v10 where parallel b-tree index scans will hang in this state. Ensure you upgrade to the latest version.

PostgreSQL docs - Wait Activity of Type IPC

PostgreSQL v10 bug report

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