Cassandra guardrails
Hyper-Converged Database (HCD) is a self-managed database powered by Apache Cassandra®, an open-source NoSQL distributed database. To ensure high availability and optimum performance, Hyper-Converged Database (HCD) databases have guardrails on underlying Cassandra functionality.
Replication within regions
Hyper-Converged Database (HCD) databases replicate data across three availability zones within the launched region to promote uptime and ensure data integrity.
Limited functions
| Parameter | Limit | Notes | ||
|---|---|---|---|---|
Large partition |
Warning |
A warning is issued if reading or compacting a partition that exceeds 100 MB. |
||
Lists |
Fixed |
Cannot
|
||
Page size |
Fixed |
Hyper-Converged Database (HCD) configures the proper page size automatically. |
||
User-defined functions (UDFs) and user-defined aggregate functions (UDAs) |
Disabled |
Hyper-Converged Database (HCD) does support UDFs and UDAs, but they must be enabled in the |
Ignored values
If you try to use a CQL command with unsupported data definition language (DDL) properties, the command works, but ignores the unsupported values.
For example:
CREATE TABLE IF NOT EXISTS library.books
(
id UUID PRIMARY KEY,
lastname text,
firstname text)
WITH nodesync={'enabled': 'true'};The table is created with the defined attributes, except for the nodesync values. The results show a warning that lists the unsupported values, which are ignored:
Warnings :
The unsupported 'nodesync' table option was ignored.Unsupported CQL commands
Operations concerning search indexes and row-level access control are not supported. This affects the following CQL commands, which are not supported in Hyper-Converged Database (HCD):
-
CREATE SEARCH INDEX -
DROP SEARCH INDEX -
ALTER SEARCH INDEX CONFIG -
ALTER SEARCH INDEX SCHEMA -
COMMIT SEARCH INDEX -
REBUILD SEARCH INDEX -
RELOAD SEARCH INDEX -
RESTRICT ROWS -
UNRESTRICT ROWS
For a list of supported CQL commands, see the CQL quick reference.
