The following restrictions apply to transitions between read-write, read-only and relocate modes:
Temporary dbspaces:
A database does not require a temporary dbspace. However, most commands require some temporary working space and return an error if no temporary dbspace exists. If a database does have one or more temporary dbspaces, there must be at least one read-write dbspace.
Altering dbspaces:
The sole read-write main dbspace may be altered read-only. There must be no active, committed or applied read-write transactions in the transaction manager or an error results. The stored procedure sp_iqtransaction displays transaction status.
The sole read-write dbspace may not be altered relocate.
A relocate mode dbspace may be altered read-write or read-only.
A read-only dbspace may be altered relocate unless it contains the special database structures.
Alter read-write of any read-only dbspace that is a read-only hardware device that is “frozen” or of any device that does not have write privilege fails with an OS file open error.
Any modification of any object in an IQ store fails if there are no read-write dbspaces in that store. Objects include table, index or internal database structures such as the backup identity object. Database backups require a read-write dbspace.
Dropping dbspaces:
Tables and indexes may be dropped or modified even if they are wholly contained on read-only and/or relocate dbspaces.
Read-only and relocate mode dbspaces may be dropped if they are empty. If a read-only dbspace contains the special structures, it is not empty, and the structures will only move if a new dbspace is created in that store or if an existing dbspace of that store is altered read-write. The stored procedure sp_iqdbspace may be used to display the location of the special structures. Drop of a read-only dbspace does not require read-write access to the device.
Verification and recovery:
sp_iqcheckdb does not require read-write space. sp_iqcheckdb will work normally when there are no read-write main dbspaces.
-iqdroplks will not update the freelist if there is no read-write main dbspace. The sp_iqcheckdb command, however, completes normally and reports results.
Forced recovery does not require read-write dbspace to open the database. However, if all main dbspaces were read-only both before and after the forced recovery, the database fails at the first checkpoint when it tries to write the rebuilt freelist.
Avoid altering a read-write dbspace may to read-only mode if there are active read-write transactions. After completion of all read-write transactions that were active when the dbspace was read-write, you may alter it to relocate mode and then from relocate to read-only mode.
The server parameter -iqro 1 opens the dbspaces of the writeable main store, i.e. the main store of a single-node or multiplex write server database or the local store of a multiplex query server database, in read-only mode. All read-write commands, including ALTER DBSPACE, require the writeable IQ Main Store be in read-write mode. The -iqro and -r options open the IQ Temporary Store in read-write mode, but the catalog dbspaces in read-only mode.
