RDF/IMP and IMPX System Management Manual (RDF 1.3+)

Introducing RDF
Compaq NonStop™ RDF/IMP and IMPX System Management Manual—522204-001
1-13
Extractor Process
the beginning of the next buffer. The extractor never waits for more than one second to
send data to the receiver. If a buffer is not filled within a second, the extractor transmits
the buffer (even though it is not filled).
When the extractor has no information to send from the audit trail, it transmits a buffer
containing no audit images (an empty buffer) to the receiver. When it receives an empty
buffer, the receiver process generates an RDF control-point record in each image trail.
Therefore, even when no TMF transactions are generated on the primary system, RDF
adds internal control points to the image trail on the backup system. The file-filling rate
for RDF control point records is very slow and is normally not noticeable.
Figure 1-4. Extractor Process Operation
Note. RDF does not replicate SQL/MP DDL operations on tables. For more information about
SQL/MP DDL operations and databases on a system protected by the RDF product, see
SQL/MP Databases
.
28 KB Buffers
Audit
File
Master Audit Trail (MAT)
Primary Disk Mirror Disk
56 KB
Read
Audit
File
56 KB
Read
Extractor
(incl. Filter)
Unneeded Data
Discarded
Expand Lines
28 KB Per Message
To Receiver
Primary node