Postgres Plus xDB Replication Server with Multi-Master User's Guide : 9.1 Permitted Database Server Configurations

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Postgres Plus Advanced Server xDB Replication Server User's Guide

 

9.1 Permitted Database Server Configurations

Depending upon the database products you are using with xDB Replication Server (Oracle, SQL Server, PostgreSQL, or Postgres Plus Advanced Server) along with the compatibility configuration mode if you are using Advanced Server, certain combinations of a source database server and a target database server are not permitted for a publication and its associated subscription in a single-master replication system.

Similarly, only certain combinations of database products and Advanced Server compatibility configuration modes can be used together in a multi-master replication system.

For a single-master replication system, the source refers to the database server of the publication database. The target refers to the database server of the subscription database.

For a multi-master replication system, all of the participating database servers act as both a source and a target for all other participating database servers, so the restrictions pertain to the combinations of database servers and compatibility configuration modes that can be used together in the same multi-master replication system.

This section presents the specific combinations of database server configurations that can be used for a publication and its associated subscription in a single-master replication system, and the combinations of database server configurations that can be used in a multi-master replication system.

9.1.1 Advanced Server Compatibility Configuration Modes

Postgres Plus Advanced Server supports two compatibility configuration modes of operation, which are the following:

    Oracle compatible configuration mode. Operations are performed using Oracle syntax and semantics for data types, functions, database object creation, and so forth. This mode is useful when your applications are migrated from Oracle, or you want your applications built in an Oracle compatible fashion.

    PostgreSQL compatible configuration mode. Operations are performed using native PostgreSQL syntax and semantics. This mode is useful when your applications are migrated from PostgreSQL, or you want your applications built in a PostgreSQL compatible fashion.

For more information on features supported in Oracle compatible configuration mode, see the Oracle Compatibility Developer’s Guide located on the Postgres Plus Documentation web page (http://www.enterprisedb.com/learning/documentation.do)

The compatibility configuration mode is selected at the time you install Postgres Plus Advanced Server.

9.1.2 Permitted SMR Source and Target Configurations

The following table shows the combinations of source and target database server products and Advanced Server compatibility configuration modes permitted by xDB Replication Server for single-master replication systems:

Table 7 – Permitted Source and Target Configurations

Source \ Target

Oracle

Microsoft SQL Server

PostgreSQL

Postgres Plus Advanced Server (Oracle compatible)

Postgres Plus Advanced Server (PostgreSQL compatible)

Oracle

No

No

Yes

Yes

Yes

Microsoft SQL Server

No

No

Yes

Yes

Yes

PostgreSQL

No

Yes

Yes

Yes

Yes

Postgres Plus Advanced Server (Oracle compatible)

Yes

Yes

No

Yes

No

Postgres Plus Advanced Server (PostgreSQL compatible)

No

Yes

Yes

Yes

Yes

In the preceding table, the left hand column lists the possible source database server products including the possible Advanced Server compatibility configuration modes. The top row lists the same set of possible target database server products and Advanced Server compatibility configuration modes.

‘Yes’ at the intersection of a source and target indicates that xDB Replication Server permits replication using that combination of database server configurations for a publication and its associated subscription. ‘No’ indicates replication is not permitted for that combination.

9.1.3 Permitted MMR Database Server Configurations

For multi-master replication systems, each master node acts as both a source for all master nodes and a target for all master nodes. Thus, the permitted database servers comprising a particular multi-master replication system or cluster is determined by the overall composition of the cluster, which is initially established when selecting the database type of the master definition node (see Step 3 in Section 6.2.2).

There are two basic cluster types that can be characterized as follows:

    PostgreSQL compatible cluster. All master nodes must consist of PostgreSQL database servers or Postgres Plus Advanced Servers installed in PostgreSQL compatible configuration mode.

    Advanced Server Oracle compatible cluster. All master nodes must consist of Postgres Plus Advanced Servers installed in Oracle compatible configuration mode.

The following table summarizes the permitted database server configurations allowed in the two cluster types.

Table 8 – Permitted Database Server Configurations by Cluster Type

Database Server \ Cluster Type

PostgreSQL Compatible Cluster

Advanced Server Oracle Compatible Cluster

PostgreSQL

Yes

No

Postgres Plus Advanced Server (PostgreSQL compatible)

Yes

No

Postgres Plus Advanced Server (Oracle compatible)

No

Yes

In the preceding table, the left hand column lists the possible database server products including the possible Advanced Server compatibility configuration modes. The top row lists the supported cluster types.

‘Yes’ at the intersection of a database server and cluster type indicates that xDB Replication Server permits the database server and the specified configuration mode in the cluster type. ‘No’ indicates the database server and the specified configuration mode cannot be used in the cluster type.

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