SHOW CLUSTERS
SHOW CLUSTERS
lists the clusters configured in Materialize.
Syntax
Pre-installed clusters
When you enable a Materialize region, several clusters that are used to improve the user experience, as well as support system administration tasks, will be pre-installed.
quickstart
cluster
A cluster named quickstart
with a size of 100cc
and a replication factor of
1
will be pre-installed in every environment. You can modify or drop this
cluster at any time.
cluster
session parameter is quickstart
.
If the quickstart
cluster is dropped, you must run SET cluster
to choose a valid cluster in order to run SELECT
queries. A superuser (i.e. Organization Admin
)
can also run ALTER SYSTEM SET cluster
to change the
default value.
mz_introspection
system cluster
A system cluster named mz_introspection
will be pre-installed in every
environment. This cluster has several indexes installed to speed up common
introspection queries, like SHOW
commands and queries using the system
catalog.
To take advantage of these indexes, Materialize will automatically re-route
SHOW
commands and queries using system catalog objects to the
mz_introspection
system cluster. You can disable this behavior in
your session via the auto_route_introspection_queries
configuration parameter.
The following characteristics apply to the mz_introspection
cluster:
- You are not billed for this cluster.
- You cannot create objects in this cluster.
- You cannot drop this cluster.
- You can run
SELECT
orSUBSCRIBE
statements against system catalog objects on this cluster. This includes queries with joins, as long as the query depends only on objects in the system catalog.
mz_system
system cluster
A system cluster named mz_system
will be pre-installed in every environment.
This cluster is used for various internal system monitoring tasks.
The following characteristics apply to the mz_system
cluster:
- You are not billed for this cluster.
- You cannot create objects in this cluster.
- You cannot drop this cluster.
- You cannot run
SELECT
orSUBSCRIBE
on this cluster.
mz_probe
system cluster
A system cluster named mz_probe
will be pre-installed in every environment.
This cluster is used for uptiming monitoring.
The following characteristics apply to the mz_probe
cluster:
- You are not billed for this cluster.
- You cannot create objects in this cluster.
- You cannot drop this cluster.
- You cannot run
SELECT
orSUBSCRIBE
on this cluster.
mz_support
system cluster
A system cluster named mz_support
will be pre-installed in every environment.
This cluster is used for support to perform one-off debugging and validation.
The following characteristics apply to the mz_support
cluster:
- You are not billed for this cluster.
- You cannot create objects in this cluster.
- You cannot drop this cluster.
- You cannot run
SELECT
orSUBSCRIBE
on this cluster.
Examples
SET CLUSTER = mz_introspection;
SHOW CLUSTERS;
name replicas
--------------------- | ------------------
default | r1 (25cc)
auction_house | r1 (25cc)
mz_introspection | r1 (50cc)
mz_system | r1 (50cc)
mz_probe | r1 (mz_probe)
mz_support |
SHOW CLUSTERS LIKE 'auction_%';
name replicas
--------------------- | ------------------
auction_house | r1 (25cc)