Reload Analyzer Manual

Tandem Reload Analyzer Manual Page 16 of 42
 Generates FUP RELOAD command when percentage of average blocks per chain is below
user specified threshold.
 Performs both Vertical index-block and Horizontal data-block chain analysis.
 Diagnoses too many vertical index-blocks which cause poor random access.
 Diagnoses too many horizontal data block chains which cause very poor sequential access
(up to 128x slower).
 Displays chaining statistics including: the total number of data chains, length of longest
chain, length of shortest chain, and a histogram of all chains.
The example below shows a database structure before and after Reload Analyzer was
used to analyze and re-organize the database. Prior to reorganization, the internal
data-block chaining structure is badly fragmented (red arrows). When data-block
chains are fragmented and not sequentially organized, random physical organization
leads to poor sequential performance due to excessive disk I/O and seeking. The
result of a poorly organized database file is more physical disk I/O and more seeks
during sequential I/O operations, which in turn severely impacts sequential I/O
performance.
Figure 1.0 Benefits of Reload