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FP_NBIT_AUTOSIZE_LIMIT OptionLocate this document in the navigation structure

Limits the number of distinct values in columns that implicitly load as NBit FP.

Allowed Values

0 – 2,147,483,647

Default

1,048,576

Scope

Option can be set at the database (PUBLIC) or user level. At the database level, the value becomes the default for any new user, but has no impact on existing users. At the user level, overrides the PUBLIC value for that user only. No system privilege is required to set option for self. System privilege is required to set at database level or at user level for any user other than self.

Requires the SET ANY PUBLIC OPTION system privilege to set this option. Can be set temporary for an individual connection or for the PUBLIC role. Takes effect immediately.

Dependencies

FP_NBIT_AUTOSIZE_LIMIT applies to databases running where FP_NBIT_IQ15_COMPATIBILITY='OFF'. If FP_NBIT_IQ15_COMPATIBILITY='ON', the database engine ignores this option.

Remarks
FP_NBIT_AUTOSIZE_LIMIT limits the number of distinct values in all newly created columns without an explicit IQ UNIQUE setting. Columns constrained by the FP_NBIT_AUTOSIZE_LIMIT option load with a Flat FP or NBit FP index:
  • If FP_NBIT_AUTOSIZE_LIMIT is greater than 0 and less than 2,147,483,647, columns load with an NBit FP index
  • If FP_NBIT_AUTOSIZE_LIMIT equals 0, columns load with a Flat FP index

FP_NBIT_AUTOSIZE_LIMIT and FP_NBIT_LOOKUP_MB establish a ceiling for sizing NBit columns during data loads. As long as the number of distinct values is less than FP_NBIT_AUTOSIZE_LIMIT and the total dictionary size (values and counts) is less the FP_NBIT_LOOKUP_MB, the column loads as an NBit. If the load exceeds the FP_NBIT_AUTOSIZE_LIMIT but is less than FP_NBIT_ROLLOVER_MAX_MB, the column rolls over to Flat FP.

DML operations that exceed the FP_NBIT_ROLLOVER_MAX_MB and FP_ENFORCE_LIMITS='ON' rollback and report an error. If the FP_NBIT_ENFORCE_LIMITS='OFF', the column transitions to the next NBit level.

sp_iqindexmetadata returns details about Flat FP or NBit FP columns. sp_iqrebuildindex can change explicit or implicit NBit FP column limits, or reformat the default column index as Flat FP or NBit FP.

Additional Information
  • Reference: Building Blocks, Tables, and Procedures > System Procedures > Alphabetical List of System Stored Procedures > sp_iqrebuildindex
  • Reference: Building Blocks, Tables, and Procedures > System Procedures » Alphabetical List of System Stored Procedures > sp_iqindexmetadata