When running DML commands in multiplex, the visibility of the table rows differs for different table types. There are three types of row visibility in multiplex:
Global scope – All connections on all servers can see the rows.
Server scope – All connections on a particular multiplex server can see the rows.
Connection scope – Only a single connection on a particular multiplex server can see the rows.
Table 3-1 describes the scope pertaining to different table types:
Table type |
Data scope |
|---|---|
IQ base |
Global |
IQ temporary |
Connection |
Global temporary table |
Connection |
SA catalog (table created IN SYSTEM) |
Server |
SA temporary (table created IN SYSTEM) |
Connection |
Sybase IQ copies data in SA catalog tables on the coordinator node to the secondary node catalog store whenever a secondary node is synchronized. The data in catalog store tables is otherwise not related between secondary server and coordinator server instances. After synchronization, local SA table data on the secondary server is lost, because table data from the coordinator overwrites it.
Because CIS proxy tables point to data on remote servers,
the data scope is external. Data management for such tables is done
by the remote server.
Any schema change for tables participating in a join index is not allowed in a 15.0 or higher multiplex. Any DML operation permitted on a table participating in a join index is allowed only on the coordinator, which must be in single node mode. See “Server startup switches”.
