CREATE TABLE SYS_SNAPSHOT (
    SN_NAME     VARCHAR(255),
    SN_QUERY    VARCHAR(1024),
    SN_LAST_TS  VARBINARY(30),
    SN_IS_INCREMENTAL   INTEGER,
    SN_SOURCE_TABLE     VARCHAR(255),
    PRIMARY KEY (SN_NAME))

This table describes all defined snapshot replication relations. SN_NAME is the snapshot's name (destination table name). SN_QUERY is the query to get the data from. SN_LAST_TS is the time of the last update reflected for incremental snapshots (from the snapshot log's SNAPTIME). SN_IS_INCREMENTAL is null for nonincremental snapshots and non-null for the incremental ones. SN_SOURCE_TABLE is the source table for the incremental snapshots, NULL otherwise.

This implies that an incremental snapshot can be updated in two ways - incrementally and nonincrementally as the nonincremental definition is a subset of the incremental definition.

CREATE TABLE SYS_SNAPSHOT_LOG (
    SNL_SOURCE  varchar (320) NOT NULL,
    SNL_RLOG    varchar (320) NOT NULL,
    SNL_RPLOG   varchar (320) NOT NULL,
    primary key (SNL_SOURCE)
)

This table describes all defined snapshot replication relation logs. SNL_SOURCE is the base table for which a snapshot log is defined. SNL_RLOG is the name of the RLOG snapshot log auxiliary table. SNL_RPLOG is the name of the RPLOG snapshot log auxiliary table.