Understand query date and PI System Explorer time

The query date determines the time values PI System Explorer uses to perform these actions:

• Find and display attribute values.

• Identify current versions of objects to display and include in search results.

At the default Query Date setting, Set to Latest, PI System Explorer finds and displays the most current data for attribute values. You can override the Query Date to view values for a different time with Set Time Context. See Set time context for displayed attribute values.

Set to Latest also causes PI System Explorer to use the latest versions of objects, even if those versions are in the future, and excludes any object with an Obsolete date, even if that date is in the future.

You can change Query Date to specify a fixed date and time:

• The date and time picker lets you choose a specific date and time setting.

• The selections Set to Now and Set to Today each use the current time to establish a fixed date and time. For example, if you choose Set to Now on Monday, then on Wednesday Query Date will still be set to Monday.

  How Query Date affects PI System Explorer

  What is affected	Query Date is Set to Latest	Query Date is a fixed date and time
  All PI System Explorer objects	PI System Explorer uses the latest versions, even if those versions are in the future; it excludes any object with an obsolete date, even if that date is in the future.	PI System Explorer uses versions of objects that are in effect at that time.
  Element, model, and table versions in search	PI System Explorer returns the latest versions, even if those versions are in the future.	PI System Explorer returns the versions that are in effect at that time.
  Relative times in searches	PI System Explorer defines the current time (*) as the time of the search.	PI System Explorer defines the current time (*) as the time specified by the Query Date.
  PI data	PI data is returned at its latest snapshot value.	PI data returned is the value for the timestamp specified by the Query Date.