SQL/MX 2.x Reference Manual (H06.04+)

MXCI Commands

HP NonStop SQL/MX Reference Manual—540440-003

4-18

DISPLAY_QC Command

Considerations for DISPLAY_QC

Examples of DISPLAY_QC

The DISPLAY_QC command generates and displays selected data from the result of

the QUERYCACHE function. For a description of the result table of the QUERYCACHE

function, see the QUERYCACHE Function on page 9-108.

You can use DISPLAY_QC only within an MXCI session.

Considerations for DISPLAY_QC

Using QUERYCACHE and DISPLAY_QC

The DISPLAY_QC command provides a shortcut method of seeing the most commonly

used columns of the QUERYCACHE function.

Purpose of the QUERYCACHE Function Result

The query plan cache automatically collects statistics regarding its use. When invoked,

the QUERYCACHE table-valued function collects and returns these statistics in a

single row table. The statistics are reinitialized when an mxcmp session is started and

each mxcmp session maintains an independent set of statistics.

Result of the DISPLAY_QC Command

The DISPLAY_QC command displays these selected columns from the

QUERYCACHE function:

Note that some of the fields can take on the value OVERFLOW if the cache statistics

value is too large.

DISPLAY_QC

Column Name Type Source column in QUERYCACHE Function

AVGSIZE CHAR(8) AVG_PLAN_SIZE

CURSIZE CHAR(8) CURRENT_SIZE

MAXSIZE CHAR(8) MAX_CACHE_SIZE

NPINNED CHAR(8) NUM_PINNED

NRECOM CHAR(8) NUM_RECOMPILES

NRETR CHAR(8) NUM_RETRIES

NCACHE CHAR(8) NUM_CACHEABLE_PARSING +

NUM_CACHEABLE_BINDING

NHITS CHAR(8) NUM_CACHE_HITS_PARSING +

NUM_CACHE_HITS_BINDING