A Storage Stream is a column in a PegaRULES database table that contains property data in a compressed format. Most tables in the database contain a Storage Stream column, identified as the pzPVStream column.

Don't confuse the Storage Stream with stream processing, an unrelated feature than involves generating HTML (or XML) text from HTML rules, XML Stream rules, and other rule types.

In Oracle, Microsoft SQL Server and most other database vendor software, the Storage Stream is stored as a binary large object or BLOB data type.

For example, an aggregate such as a Value List property can have multiple values. When the system saves an object that includes an aggregate property, its values are compressed together (or "deflated") into a single column. When the instance is later opened and placed on a clipboard, the column is decompressed (or "inflated").

When deflated, the property names and values are present in a single text value. This text value has a proprietary format; the values are obfuscated.

For guidance on understanding the space requirements of the storage stream articles, see the Pega Developer Network article PRKB-12464 How to estimate disk space requirements for a PegaRULES database (Oracle).

	aggregate, Column Populator utility, exposed property, PegaRULES database, schema, stream processing
	Working with the PegaRULES database How to expose a property as a database column How to monitor Storage Stream operations How to encrypt the Storage Stream for selected classes Performance tool — Setting DB Trace Options System limits and maximums

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