Show TOC

FP_NBIT_ROLLOVER_MAX_MB OptionLocate this document in the navigation structure

Sets a threshold for the total dictionary size for implicit NBit rollovers to Flat FP.

Allowed Values

1  – 4,294,967,295

Default

16384

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_ROLLOVER_MAX_MB 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 and FP_NBIT_LOOKUP_MB establish a ceiling for sizing implicit NBit FP columns. DML operations that exceed these values check the FP_NBIT_ROLLOVER_MAX_MB limit, which sets the dictionary size (values and counts) for implicit NBit rollovers:
  • If the total dictionary size does not exceed the FP_NBIT_ROLLOVER_MAX_MB, the NBit column rolls over to a Flat FP.
  • If the dictionary size exceeds the FP_NBIT_ROLLOVER_MAX_MB limit and FP_NBIT_ENFORCE_LIMITS='ON', DML operations throw an error and roll back.
  • If the dictionary size exceeds the FP_NBIT_ROLLOVER_MAX_MB limit and FP_NBIT_ENFORCE_LIMITS='OFF' (default), DML operations throw an error, and the NBit dictionary continues to grow.
  • If FP_NBIT_ROLLOVER_MAX_MB='0', the NBit column rolls over to Flat FP.

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