Data Virtualization
Managers can create a cache entry to save query data and results and
optimize query performance.
Ensure that you meet the following requirements:
Data Virtualization users require interactive query performance to access data of any size, any
format, and any source. To avoid query executions that are time-consuming, Data Virtualization
Managers can create a cache entry to improve the performance by caching
the result set of your queries.
Try to limit the number of cache entries since it might increase the cost of compiling and
evaluating user queries, and might worsen service performance.
- Go to .
- Click Add new cache in the Active data
caches tab.
- Enter valid queries in the SQL editor to create your cache. Ensure that you specify a
schema name in your query and leave out any SQL terminators.
- From the Test queries with cache tab, you can test whether the
cache can match a query at run time, and then follow these steps:
- Enter a query in the SQL editor.
- Go to the Select from existing tab and choose the queries for which you
want to test cache impact.
- In the Selected queries section, you can edit selected queries or filter
queries by creation date, creator, execution time and types of query.
- Start the test of cache impact on selected queries by clicking Test
queries.
- Test results are displayed in the Selected queries section. The
Status column provides the following information.
- Matched to cache: Data Virtualization determined that
the cache matched with the selected queries, and if you choose to create the cache, those queries
might use the cache at run time. Other near-identical caches might override the utility of the cache
that you are creating. Whether query performance improves or not depends on other factors in the
overall query plan.
- Not matched to cache: Data Virtualization determined that the cache does
not match the selected queries, and hence, might not have any influence on query performance.
- Error: Data Virtualization cannot validate whether the selected queries
match the cache or not. Refer to the error message for details.
- Click Use this cache to apply the cache to the selected queries.
- Click Next and set the refresh rate to prevent the
cache from becoming stale by referring to the following information.
- None, manual only: To refresh a cache manually, go to
the action menu of an active cache and click Refresh now.
- Minutes: Select the interval in minutes to refresh
your cache. For example, refresh every 15 minutes.
- Hourly: Select time (minute) of the hour to refresh
your cache. For example, refresh every hour at the 30 minutes past the hour.
- Daily: Select time of the day to refresh your cache.
For example, refresh every day at 12:00 AM.
- Weekly: Select days of the week and time of the day
to refresh your cache. For example, refresh every Monday, Wednesday, and Friday at 12:00 AM.
- Monthly: Select weeks of the month, days of the
week, and time of the day to refresh your cache. For example, refresh on the first day of the month
at 12:00 AM.
- Click Next and then enter a name for your cache.
- Ensure that the summary is correct, and then click Create
cache.