Fixing issues

Overview

This chapter is for administrators. It shows which issues PI Nexus+ can fix for you, how a fix is previewed, applied and undone, and where the record of everything PI Nexus+ wrote to your PI System is.

Fixing needs the Admin role and a production license. An administrator must first allow fixes for each server (see Issue Fixes in the Administration Guide). Until any server allows a write, Fix..., Revert..., Apply plan... and the PI Nexus+ writes tab of Change History are not shown; after that, Fix... on a server whose fixes are off is disabled and says why. The Evaluation edition shows the preview but not Apply.

Which issues can be fixed

• PI Points: an attribute check whose operator is Equals. The fix sets the attribute to the value the check expects. The other operators name what a value must not be, so there is no value to write; correct those points by hand.
• Access: the issues in the table below. Every other Access issue is staged in Act (see Access).

PI Nexus+ does not change PI database security, directory groups, PI Vision, hosts, interfaces or adapters. Those issues keep their steps.

Fix one issue

1. On an issue card (the Issues page, the Issues tab of an object, or the Access Issues tab), choose Fix....
2. Read the preview: the object, what it holds now and what it becomes. For an Access issue it also shows who gains and loses a right, as Act does. The last line says whether the fix can be undone.
3. For a check that fails on several points of the same server, tick Fix all N points failing... to fix them in one go (up to 500 at a time; run it again for the rest).
4. Choose Apply fix. The dialog follows the Worker until each object ends in a state.

A fix writes as the account PI Nexus+ uses to connect to that server, and only while the object still holds the value PI Nexus+ read. Fixes on several points continue past a conflict.

Apply a plan from Act

In the Access workspace, Act > Apply plan... applies the staged plan to the server instead of exporting it. The preview lists the steps in the order they run, with the impact. The Worker applies them one after the other and stops at the first step that finds the server changed; the later steps show Not run. After the read that follows, a saved scenario shows Verified.

Revert a change in Change History

An access change that happened outside PI Nexus+ (a security entry added, an identity disabled or renamed, a mapping added or removed) shows Revert... in Change History and on the identity's Change History tab. It writes the earlier value back, if the object still holds what that change produced, and says when the change was detected. The row then shows Reverted by the administrator. A change that a PI Nexus+ fix made shows By PI Nexus+ fix, and so does a PI point attribute change that a fix or a Compression Tuning apply wrote.

Only the latest change of an object can be reverted. PI database security, directory groups, PI Vision permissions and the creation or removal of identities are not reverted.

What PI Nexus+ wrote

Change History has two tabs once a server allows a write or something has been written: Changes, what the scans found changed in PI whoever made the change, and PI Nexus+ writes, everything PI Nexus+ wrote or tried to write to a PI System, newest first: who asked, what it was and how it went. A write that failed or changed nothing, and an analysis recalculation, appear only there. A change a write made appears in both, marked By PI Nexus+ fix in Changes and linked to its record. Search finds a write by its summary, server, who asked, or an object it wrote (a point, an identity, an analysis). Filters narrows it by Type (point fixes, Access, Compression Tuning, recalculation) and Result: Needs attention is a write with an object that failed, was blocked or is in a conflict nobody has decided, or a recalculation that was not sent or not confirmed. Everyone can read it, except that Access fixes are shown to administrators only; undoing is for administrators. Click a row for each object with its values before and after.

It lists issue fixes, applied plans, reverts and undos, and also the writes of two other features: each Compression Tuning apply (the row names Compression Tuning and links to the tuning run) and each analysis Recalculation (the row links to the request). Earlier ones appear too.

Undo a fix

1. Open the fix on Change History > PI Nexus+ writes and choose Undo....
2. Check what each object holds now and what it will be restored to, and choose Undo.

An undo is a fix of its own, on the same page. It writes back the recorded earlier value only while the object still holds what the fix wrote. When it does not, the object shows Conflict with three values: what the fix wrote, what the object holds now and the original value. Choose Keep current values to leave it, or Restore anyway to write the original; the decision is recorded.

The preview says how exactly an undo restores:

• Exact: the same values go back (point attributes, security strings, enabled flags).
• Equivalent: the same meaning with a new ID. A removed mapping is created again for the same account and identity.
• Cannot be undone: a recalculation overwrites archived values.

Compression applies and recalculations

Each Compression Tuning apply, of a recommendation or of custom settings, is one fix with the original and the new deviations of every point. Undo... restores the original exception and compression deviations while the point still holds the applied ones. It needs Compression Tuning on the PI Data Archive's Writes tab in Admin, the permission applying needs (see Compression Tuning).

A recalculation request is one fix with a line per analysis: Queued while it waits, Applied once the request was sent, Failed when it was not sent or its sending is unconfirmed. It cannot be undone. Follow it as described in AF Analyses and Recalculation.