Easy Chart Tag Quality Going Bad Randomly

I created an easy chart Friday with 5 tags coming in from PLC’s around the warehouse. I went through all of the settings recommended by Inductive, and different forum posts. I created the table seamlessly, with tag history enabled, and it ran for the remainder of the day. Coming in today, I see this error:
Error running query:
Tag Density Histogram Query
Range: Mon Nov 06 15:00:00 MST 2017->Mon Nov 06 16:59:59 MST 2017
Paths:
tag
tag
tag
tag
tag
@0ms
On: Main Window.Root Container.Easy Chart

The chart is now red, and not reading any of the inputs. I have a SQL server running off of the data filtering through ignition using the transaction groups, and everything in regards to tag quality outside of this instance, seemingly points to no problem.
I deleted the chart, and went through the steps/settings that I did last week, and it still comes up with this error.

On: Main Window.Root Container.Easy Chart
caused by GatewayException: Error executing tag history query. Please verify that the connection is available, and that tag history is being stored to it.
From details page of error:
caused by Exception: Error executing tag history query. Please verify that the connection is available, and that tag history is being stored to it.

I’m on the trial version at the moment, but from my understanding that shouldn’t hinder me at all.
Thanks so much in advance, I look forward to any input you guys have!

Well, it’ll hinder you every two hours when it stops recording…

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I’m aware of that. I was assuming that wasn’t the problem, given it’s worked through multiple refreshes of the trial period. My company hasn’t committed to a full purchase yet, so this is what I’m currently limited to.

Check the gateway’s logs (Status -> Diagnostics -> Logs) when you get this error on the client; there may be more information about why the query isn’t returning.

Where is the status selection that I’m looking for? Right clicking the graph and selecting “run diagnostics” returns this
Checking Easy Chart…
TagDensityQuery(tags=[[~]Totals/Cover Total, [~]Totals/Final Total, [~]Totals/Gear Total, [~]Totals/Stem Total, [~]Totals/Tripspring Total]): SQL Error
TagHistoryQuery(tags=[prov:default:/tag:Totals/Cover Total, prov:default:/tag:Totals/Final Total, prov:default:/tag:Totals/Gear Total, prov:default:/tag:Totals/Stem Total, prov:default:/tag:Totals/Tripspring Total]): SQL Error

Saying that it’s a SQL error, however these tags are working flawlessly across both other parts of this project and the sql database. Any ideas?
Thanks so much for the response!

“Status => Diagnostics => Logs” is in the gateway web interface, not in the designer.

DatasourceForwardTransaction 08Nov2017 15:26:58 Error forwarding data: Invalid object name ‘sqlth_sce’.
OpcUaConnection 08Nov2017 15:26:56 Keep Alive failureCount=83 exceeds failuresAllowed=1; disconnecting.
OPC-UA Server.ReadService 08Nov2017 15:26:56 Returning ServiceFault for request: com.inductiveautomation.opcua.types.messages.ReadRequest@68640e58. StatusCode=StatusCode[Severity=Bad, Subcode=Bad_SessionIdInvalid]
MemoryForwardTransaction 08Nov2017 15:26:46 Error forwarding data: Invalid object name ‘sqlth_sce’.
OpcUaConnection 08Nov2017 15:26:46 Keep Alive failureCount=82 exceeds failuresAllowed=1; disconnecting.

I deleted some random tables that showed up in my SQL Database, and this was definitely the title to one of them. What does that entail?

Yes, the sqlth_sce (sql tag history _ scan class executions) table is needed by default - particular for the ‘tag density query’ that the easy chart automatically runs (which fills in the date range slider).

If you don’t want Ignition’s historian to automatically flag ‘stale’ data (based on historical scan class execution rate) then you can go into the settings for the history provider (Configure → Tags → History) and at the bottom of the ‘advanced’ options uncheck the ‘Stale Data Detection’ flag:

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I restarted the right module, to reinstate those tables that were deleted in my ignorance! Thank you so much. Everything’s up and groovy.

I have been fighting Deadlocks on sqlth_sce for weeks, disabling this got everything moving again. Probably not the best long term solution, but I’ve got charts with data in them for tonight. I’m replying in case anyone comes across this same issue.