FAST Search 2010: Feeding limitations for FAST Search for SharePoint


Overall document size is limited by the Search Service Application’s configuration value MaxDownloadSize. The default for this value is 64MB with a maximum configurable value of 2GB. However, setting MaxDownloadSize to a value greater than 726MB when using FAST Search for SharePoint is not supported and may significantly increase the risk of introducing failures or performance issues into the system.

More Information

The following sections provide an overview of the limitations within the FAST Search for SharePoint feeding chain.

FAST Search Service Application

The MaxDownloadSize configuration value can be retrieved and modified via PowerShell using the following commands from within the SharePoint 2010 Management Shell.

1. Get a reference to the current FAST Search Service Application and store it in a variable by running:
$ssa = Get-SPEnterpriseSearchServiceApplication –Identity [FAST Search SSA Name]

2. Retrieve the current value of the MaxDownloadSize from the MSSConfiguration table:


3. To modify MaxDownloadSize and increase or decrease the value:
$ssa.SetProperty(“MaxDownloadSize”, [new value in MB] )

4. Update the SSA’s configuration:

Document Processor

During Document Processing, a 2GB memory limit exists per process. Exact memory consumption during processing is dependent upon multiple factors including the Index Profile and the complexity of each document. Documents that exceed the DocProc's 2GB memory limitation are rejected and the following warnings raised.
Memory usage is <> MB. Limit: 2048 megabytes. Terminating voluntarily.
Last 4 samplings on memory usage averaged at <> MB, which beyond 2048 MB limit

Index Schema

Documents that successfully pass through the feeding chain may have their content truncated in some situations. This behavior is expected for large documents due to the default configuration limits of the MaxIndexSize of the “Body” property in the default Index Schema. After increasing MaxDownloadSize for the FAST Search SSA, admins should verify any detected document truncation issues as it could result in unexpected search results for users. In FAST Search for SharePoint the MaxIndexSize for the Body property defaults to 16MB, setting this value higher than the default may adversely impact performance.

Documents that are truncated during process will raise the following warning in the doclog:
max-index-size limit <size in bytes> bytes for field body exceeded (field length is <size in bytes> bytes).
For more information on this error, including how to change the MaxIndexSize property, please review the following knowledge base article: FAST Search: Document has been truncated


Article ID: 2702836 - Last Review: 8 May 2012 - Revision: 1