Too many tags in readBlocking?

Ignition
1

Is there a limit of how many tags in a single system.tag.readBlocking? If so, I think I might have reached it. The error I'm getting is: "java.util.concurrent.TimeoutException: null"

I'm trying to read 2.2 million tags. What's the tag limit? How many is too many for such a call?

tagPaths = [] #100K tags
columns = ['Enabled', 'TagType', 'DataType', 'AccessRights', 'Documentation', 'Tooltip', 'EngUnit', 'EngHigh', 'EngLow', 'EngLimitMode', 'ScanClass', 'Deadband', 'DeadbandMode', 'HistoryEnabled', 'HistoricalScanclass', 'HistoricalDeadband', 'HistoricalDeadbandMode', 'HistoryMaxAge', 'HistoryMaxAgeMode', 'InterpolationMode', 'OpcItemPath', 'OpcServer']
qvs = system.tag.readBlocking(['%s.%s' % (tagPath, column) for tagPath in tagPaths for column in self.columns])
# 100K tags * 22 columns
2

There's no explicit quantity limit, but I'm gonna guess you've hit a practical limit. Unless you are trying to do this from the designer or a Vision client, in which case you've probably hit the 60 second timeout on traffic between designer/client and the gateway.

3

With trying to read 2.2 million qualified values, that gives you 6.6 milliion points of data.
Have you tried using system.tag.getConfiguration()

4

system.tag.getConfiguration is too slow for what I need. It takes only 1 base path, but I need a list of tags.

5

It is running this from the gateway script. This is the error on the log.

Scripting[system_util_tag]	09Nov2026 21:58:15	Error during blocking read of tags through scripting.
java.util.concurrent.TimeoutException: null

at java.base/java.util.concurrent.CompletableFuture.timedGet(Unknown Source)

at java.base/java.util.concurrent.CompletableFuture.get(Unknown Source)

at com.inductiveautomation.ignition.gateway.script.GatewayTagUtilities.readBlockingImpl(GatewayTagUtilities.java:246)

at com.inductiveautomation.ignition.common.script.builtin.AbstractTagUtilities.readBlocking(AbstractTagUtilities.java:510)

at jdk.internal.reflect.GeneratedMethodAccessor90.invoke(Unknown Source)

at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)

at java.base/java.lang.reflect.Method.invoke(Unknown Source)

at org.python.core.PyReflectedFunction.__call__(PyReflectedFunction.java:190)

at com.inductiveautomation.ignition.common.script.ScriptManager$ReflectedInstanceFunction.__call__(ScriptManager.java:553)

at org.python.core.PyObject.__call__(PyObject.java:461)

at org.python.core.PyObject.__call__(PyObject.java:465)

at org.python.pycode._pyx266356.export$7(:97)

at org.python.pycode._pyx266356.call_function()

at org.python.core.PyTableCode.call(PyTableCode.java:173)

at org.python.core.PyBaseCode.call(PyBaseCode.java:168)

at org.python.core.PyFunction.__call__(PyFunction.java:437)

at org.python.core.PyMethod.__call__(PyMethod.java:156)

at org.python.pycode._pyx266352.cache_tags$18(:548)

at org.python.pycode._pyx266352.call_function()

at org.python.core.PyTableCode.call(PyTableCode.java:173)

at org.python.core.PyBaseCode.call(PyBaseCode.java:187)

at org.python.core.PyFunction.__call__(PyFunction.java:449)

at org.python.core.PyMethod.__call__(PyMethod.java:171)

at org.python.pycode._pyx266352.cache_provider_configs$15(:486)

at org.python.pycode._pyx266352.call_function()

at org.python.core.PyTableCode.call(PyTableCode.java:173)

at org.python.core.PyBaseCode.call(PyBaseCode.java:306)

at org.python.core.PyBaseCode.call(PyBaseCode.java:158)

at org.python.core.PyFunction.__call__(PyFunction.java:437)

at org.python.core.PyMethod.__call__(PyMethod.java:156)

at org.python.pycode._pyx266370.handleMessage$1(:10)

at org.python.pycode._pyx266370.call_function()

at org.python.core.PyTableCode.call(PyTableCode.java:173)

at org.python.core.PyBaseCode.call(PyBaseCode.java:306)

at org.python.core.PyFunction.function___call__(PyFunction.java:474)

at org.python.core.PyFunction.__call__(PyFunction.java:469)

at org.python.core.PyFunction.__call__(PyFunction.java:464)

at com.inductiveautomation.ignition.common.script.ScriptManager.runFunction(ScriptManager.java:847)

at com.inductiveautomation.ignition.common.script.ScriptManager.runFunction(ScriptManager.java:829)

at com.inductiveautomation.ignition.gateway.project.ProjectScriptLifecycle$TrackingProjectScriptManager.runFunction(ProjectScriptLifecycle.java:868)

at com.inductiveautomation.ignition.common.script.message.MessageHandlerRunnable.run(MessageHandlerRunnable.java:121)

at java.base/java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)

at java.base/java.util.concurrent.FutureTask.run(Unknown Source)

at java.base/java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(Unknown Source)

at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)

at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)

If there is a limit, it would be nice to know what that is, so I can slice the list of tagpaths into a smaller list.

6

You've hit a timeout, so as PTurmel says, there is no "limit", however depending on hardware this will take too long and hit a timeout limit. We can't answer the value of how many to batch this down to because it is very dependent on your hardware/network. Running this on a Raspberry Pi or a datacenter cluster will give very different results. 2.2 million tags might be OK for a cluster, but 1000 tags may be too much for a RPi.

What you will have to do is testing on your side to determine how many tags you can read without overloading your network/server, then add in some margin and set that as your batching value (and gracefully handle any Timeout's with a retry on smaller batches).

7

Dare I ask...why?

What's the Y problem you're trying to solve with this X task statement?