Dbspace Updates in Multiplex

Dbspace updates on multiplex differ slightly from those on simplex databases.

In general, when updating shared dbspaces:

Only the coordinator can manipulate shared IQ dbspaces.
Before you can drop a shared dbspace file, you must alter the file to read-only mode. All servers must have advanced to the version corresponding to the ALTER READONLY statement, and must have returned all reserved blocks on the file.
CREATE DBSPACE, ALTER DBSPACE and DROP DBSPACE commands for main and catalog dbspaces are allowed only on the coordinator
For IQ_SHARED_TEMP behavior, see Multiplex Transactions > DDL Commands > Role Restriction > Dbspace Updates in Multiplex > Updates on IQ_SHARED_TEMP.

Due to delays in TLV propagation and version maintenance, there may be a delay of a few minutes before you can drop an empty dbfile or dbspace. You see a Command not replayed error. To perform the DROP DBSPACE or ALTER DBSPACE DROP FILE commands, the OkToDrop column reported by the sp_iqdbspace and sp_iqfile procedures must indicate “Y.”

Never enter ALTER DBSPACE DROP FILE when connected using -iqro. ALTER DBSPACE DROP FILE returns the error Modifications not permitted for read-only database if the server is started with the -iqro option.

Updates on IQ_SYSTEM_TEMP
Familiarize yourself with requirements before updating IQ_SYSTEM_TEMP dbspaces.
Updates on IQ_SYSTEM_MAIN
The IQ_SYSTEM_MAIN dbspace manages important database structures including the free list, which lists blocks in use.
Updates on IQ_SHARED_TEMP
When you update IQ_SHARED_TEMP dbspaces, certain restrictions apply.
Adding a Catalog Dbspace
Under normal circumstances, you will need not add catalog dbspaces; they automatically grow as needed. However, if your catalog dbspace file is on constrained storage, you may need to add a new catalog dbspace to accommodate catalog data.
Dropping a Catalog Dbspace
Under normal circumstances, you need not remove catalog dbspaces; they automatically grow as needed.

Parent topic: DDL Commands