imci
Specifies whether to enable the In-Memory Column Index (IMCI) feature. Valid values are ON, OFF.
NOTE: Only polardb MySQL Cluster version is available. The cluster with minor version number of 8.0.1 supports the column index feature, and the specific kernel version must be 8.0.1.1.22 or above. NOTE: The single node, the single node version of the history library, and the cluster version of the history library do not support column save indexes.