CLEAR CACHE

Reference and syntax for the CLEAR CACHE command.

Clears the content of various caches on the engine the command is executed on.

This command is useful for performance testing. There is no need to call this during normal operation. Firebolt automatically evicts entries from caches that haven’t been accessed for some time. To view the current state of the cache, refer to the information_schema.engine_caches view.

Syntax

CLEAR [<cache_name>] CACHE

If a cache name is specified, clears this cache. Otherwise, clears all caches, including the caches for all tables and indexes.

CLEAR CACHE FOR [<table_or_index_name>]

Clears the cache for a specific table or index. With this, all data of the table or index needs to be fetched from object storage again. The performance will be similar to the performance on an engine that was just started.

Parameters

Parameter	Description
<cache_name>	The name of the cache to clear.
<table_or_index_name>	The name of a table or index to clear all cached data from.

Available Caches

Cache Name	Description
EXTERNAL DATA	Cache for external data like metadata or data files of Iceberg tables.
QUERY	Subresult and result cache.
PARQUET STATISTICS	Cache for parsed column statistics from parquet footers.
AUTOMATED COLUMN STATISTICS	Cache for automated column statistics.
HISTORY BASED STATISTICS	Cache for history-based statistics.
VECTOR INDEX	Clears the vector search index cache.

Example 1

The following example clears all caches on the engine the command is executed on:

CLEAR CACHE

Example 2

The following example clears the query cache on the engine the command is executed on:

CLEAR QUERY CACHE