{"record":{"id":"8b2d3735ab27c353","repo":"apache/pulsar","slug":"internal-error-updating-function-at-the-leader","errorCode":null,"errorMessage":"Internal Error updating function at the leader","messagePattern":"Internal Error updating function at the leader","errorType":"exception","errorClass":"IllegalStateException","httpStatus":null,"severity":"error","filePath":"pulsar-functions/worker/src/main/java/org/apache/pulsar/functions/worker/FunctionMetaDataManager.java","lineNumber":246,"sourceCode":"            serviceRequest.setRequestId(UUID.randomUUID().toString());\n            toWrite = serviceRequest.toByteArray();\n        }\n        try {\n            TypedMessageBuilder<byte[]> builder = exclusiveLeaderProducer.newMessage()\n                    .value(toWrite)\n                    .property(versionTag, Long.toString(functionMetaData.getVersion()));\n            if (workerConfig.getUseCompactedMetadataTopic()) {\n                builder = builder.key(FunctionCommon.getFullyQualifiedName(functionMetaData.getFunctionDetails()));\n            }\n            lastMessageSeen = builder.send();\n            if (delete) {\n                needsScheduling = processDeregister(functionMetaData);\n            } else {\n                needsScheduling = processUpdate(functionMetaData);\n            }\n        } catch (Exception e) {\n            log.error().exception(e).log(\"Could not write into Function Metadata topic\");\n            throw new IllegalStateException(\"Internal Error updating function at the leader\", e);\n        }\n\n        if (needsScheduling) {\n            this.schedulerManager.schedule();\n        }\n    }\n\n    private void checkRequestOutDated(FunctionMetaData functionMetaData, boolean delete) {\n        FunctionDetails details = functionMetaData.getFunctionDetails();\n        if (isRequestOutdated(details.getTenant(), details.getNamespace(),\n                details.getName(), functionMetaData.getVersion())) {\n            log.debug().attr(\"tenant\", details.getTenant())\n                    .attr(\"namespace\", details.getNamespace())\n                    .attr(\"functionName\", details.getName())\n                    .attr(\"version\", functionMetaData.getVersion())\n                    .log(\"Ignoring outdated request version\");\n            if (delete) {\n                throw new IllegalArgumentException(","sourceCodeStart":228,"sourceCodeEnd":264,"githubUrl":"https://github.com/apache/pulsar/blob/820761864ed8e2a7d2e52dd9763ad2ae117c1395/pulsar-functions/worker/src/main/java/org/apache/pulsar/functions/worker/FunctionMetaDataManager.java#L228-L264","documentation":"updateFunctionOnLeader processes the metadata update (register/update/delete) and writes it into the function metadata topic via processUpdate/processDeregister. Any exception thrown during that processing is wrapped in IllegalStateException(\"Internal Error updating function at the leader\", e), indicating the leader failed to persist the change — the original cause is attached.","triggerScenarios":"Calling updateFunctionOnLeader where processUpdate/processDeregister throws — e.g. the update is outdated (IllegalArgumentException from processUpdate), topic producer failures, serialization errors, or scheduler state corruption while writing to the function metadata topic.","commonSituations":"Metadata topic producer is disconnected or the topic is unavailable; concurrent updates with stale versions triggering the outdated-request path; worker bookie/storage problems making the topic write fail.","solutions":["Inspect the wrapped cause (e.getCause()) — the fix depends on it (stale version vs producer/topic failure).","If the cause is the 'out of date' IllegalArgumentException, re-fetch the current function metadata and retry with the fresh version.","Verify the function metadata topic exists and the broker/bookies backing it are healthy.","Retry the update after the leader's producer reconnects; check leader worker logs for the 'Could not write into Function Metadata topic' error for the root cause."],"exampleFix":"// before\nmanager.updateFunctionOnLeader(meta, false);\n// after\ntry {\n    manager.updateFunctionOnLeader(meta, false);\n} catch (IllegalStateException e) {\n    Throwable cause = e.getCause();\n    if (cause instanceof IllegalArgumentException) {\n        FunctionMetaData fresh = fetchCurrentMetaData(tenant, namespace, functionName);\n        manager.updateFunctionOnLeader(fresh, false);\n    } else {\n        throw e;\n    }\n}","handlingStrategy":"try-catch","validationCode":"// verify metadata topic health before writing\nTopicName metaTopic = TopicName.get(\"persistent://public/functions/metadata\");\nadmin.topics().getStats(metaTopic.toString()); // throws if topic/broker unavailable","typeGuard":null,"tryCatchPattern":"try {\n    manager.updateFunctionOnLeader(meta, delete);\n} catch (IllegalStateException e) {\n    Throwable cause = e.getCause();\n    if (cause instanceof IllegalArgumentException) {\n        refreshAndRetry(meta, delete);\n    } else {\n        throw new FunctionUpdateException(cause); // topic/storage problem\n    }\n}","preventionTips":["Always inspect the wrapped cause before deciding on a fix.","Keep the function metadata topic and its backing bookies healthy/monitored.","Use read-modify-write with version increment for all metadata updates."],"tags":["pulsar-functions","metadata-topic","write-failure"],"backgroundTag":"internal-write-failure","analyzedSha":"820761864ed8e2a7d2e52dd9763ad2ae117c1395","analyzedAt":"2026-09-06T00:14:20.138Z","contentChangedAt":"2026-09-06T00:14:20.138Z","schemaVersion":2},"datasetVersion":"2026-09-14T05:17:10.506Z"}