INITIALLOADOPTIONS

Valid For

Valid for Initial Load Extract for PostgreSQL and SQL Server.

Description

This parameter is used to enable precision instantiation for an initial load Extract, which allows initial data instantiation without incurring application downtime. The Precise instantiation is achieved by creating a consistent point of the database in relation to the transaction log, or identifiable by a transaction log position like LSN. The initial-load Extract reads the data sets that are already committed up to the consistent point. Changes after that consistent point are not captured by the initial load Extract. A CDC Extract can be used in conjunction to capture the transactions after the precise instantiation LSN.

Queries in snapshot isolation level returns data that are committed by the time the transaction is started. Uncommitted changes after the transaction is started are ignored.

By default, precise instantiation is disabled. To enable precise instantiation, use the INITIALLOADOPTIONS parameter with the USESNAPSHOT option when configuring an online load Extract.

Syntax

INITIALLOADOPTIONS USESNAPSHOT

Examples

The example shows the use of the parameter with the USESNAPSHOT option in the initial load Extract parameter file. The name of the initial load Extract is extinit.

EXTRACT extinit
INITIALLOADOPTIONS USESNAPSHOT
SOURCEDB psql_src USERIDALIAS ggma PASSWORD We1come23 
EXTFILE ei, MEGABYTES 500, PURGE
TABLE public.*;

For details on implementation steps, see Add Initial Load Extract for PostgreSQL.