SQL/MP Query Guide

The Optimizer
HP NonStop SQL/MP Query Guide—524488-003
2-2
SQL Components and the Optimizer
For embedded SQL, the model in Figure 2-1 would not include the SQLCI process,
and the SQLCI2 process would be replaced by the user process.
In Figure 2-1, each disk process communicates with a different table. Multiple disk
processes can also work on separate partitions of a table or index, thus providing
parallel access to a table. To facilitate faster execution, SQL can also process queries
in parallel by dividing the query into smaller tasks assigned to separate processors. For
more information, see Requesting Parallel Processing on page 4-13 and How Parallel
Processing Is Implemented on page 4-14.
These paragraphs explain, in more detail, the tasks performed by the executor, the file
system, and the disk process in executing a query.
Figure 2-1. SQL Components That Execute a Query
SQLCI Process
SQLCI2 Process
SQL Executor
SQL File System
$V1.SVOL.TABLE1
Disk Process Dis k Process Disk Process Disk Process
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$V 2. SV OL .TA BLE2 $ V3 .S VO L . TAB L E3 $ V4 .S VO L. TAB LE 4
VST0201.vsd