From 7f8d6840b4a7ba4d10ab074fdc56d27b0111e734 Mon Sep 17 00:00:00 2001 From: Silas Mendes Date: Wed, 27 May 2026 17:54:10 +0100 Subject: [PATCH] Clarify Parquet continuous export performance for wide tables --- .../kusto/management/data-export/continuous-data-export.md | 1 + 1 file changed, 1 insertion(+) diff --git a/data-explorer/kusto/management/data-export/continuous-data-export.md b/data-explorer/kusto/management/data-export/continuous-data-export.md index 40f751cabc..6c6778473d 100644 --- a/data-explorer/kusto/management/data-export/continuous-data-export.md +++ b/data-explorer/kusto/management/data-export/continuous-data-export.md @@ -143,6 +143,7 @@ To define continuous export to a delta table, do the following steps: * The following formats are allowed on target tables: `CSV`, `TSV`, `JSON`, and `Parquet`. * Continuous export isn't designed to work over [materialized views](../materialized-views/materialized-view-overview.md), since a materialized view might be updated, while data exported to storage is always appended and never updated. * Continuous export can't be created on [follower databases](/azure/data-explorer/follower) since follower databases are read-only and continuous export requires write operations. +* Continuous export to Parquet can experience reduced performance for tables with a large number of columns due to per-column encoding overhead. * Records in source table must be ingested to the table directly, using an [update policy](../update-policy.md), or [ingest from query commands](../data-ingestion/ingest-from-query.md). If records are moved into the table using [.move extents](../move-extents.md) or using [.rename table](../rename-table-command.md), continuous export might not process these records. See the limitations described in the [Database Cursors](../database-cursor.md#restrictions) page. * If the artifacts used by continuous export are intended to trigger Event Grid notifications, see the [known issues section in the Event Grid documentation](/azure/data-explorer/ingest-data-event-grid-overview#known-event-grid-issues).