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