ALTER SYSTEM is prohibited (configuration changes should be performed via shardmanctl update).

ALTER TABLE is prohibited for partitions of sharded tables.

All forms of ALTER TABLE are prohibited for sharded or global tables except these:

All limitations for ALTER TABLE apply.

Only the global user can create sharded or global table.

A temporary table cannot be created as sharded or global.

Sharded or global tables and local tables cannot be dropped in the same statement.

Partitions of a sharded table cannot be dropped.

CREATE INDEX CONCURRENTLY is a non-transactional command. If a problem arises while building index on sharded or global tabe, such as network failure, deadlock or a uniqueness violation in a unique index, the CREATE INDEX CONCURRENTLY will partially fail, but can leave behind valid or invalid indexes on Shardman cluster nodes. Also an index can be completely missing on some nodes. In the later case DROP INDEX will fail to drop the index. The recommended way to remove such index cluster-wide is to use DROP INDEX IF EXISTS command. Note that DROP INDEX CONCURRENTLY is not supported on sharded tables, so this operation should be better performed in a maintenance window.

UPDATE of a sharded table is executed as a series of usual UPDATEs if it doesn't move data between partitions or subpartitions. Otherwise it is executed internally as DELETE from one partition and INSERT into another (so called target partition). If a partition where UPDATE INSERTs data, is going to be UPDATED in the same statement, an error will be raised. In practice this means that if UPDATE moves data between partitions, you should explicitly exclude target partition from updating in WHERE clause of the statement.

INSERT INTO table_name... ON CONFLICT [conflict_target] conflict_action [WHERE condition] command is not supported on foreign tables when conflict_target is DO UPDATE. For sharded tables it is supported if expressions in SET and WHERE clause can be safely deparsed (currently deparsing of sqlvalue-functions, parameters and subqueries inside these clauses is not supported) and a non-partial unique index, containing only table columns, corresponds to conflict_target expression. This is usually the case with table's primary key.

Global users can be created only by user with CREATEROLE permission on all cluster nodes.

Global roles cannot be renamed.

Global and local roles cannot be dropped in the same statement.

GRANT to a local and global role in the same statement is prohibited.

REVOKE from a local and global role in the same statement is prohibited.

Schemas containing global or sharded tables cannot be renamed. Shardman service schemas (shardman and shardman_internal) cannot be renamed or dropped.

Shardman cluster servers cannot be dropped. Use Shardman tools to remove servers from the cluster.

DROP TYPE CASCADE is prohibited if it affects types used in global or sharded tables.