From 2f23de0bb419cc6987ae6711b0d6749266a522a9 Mon Sep 17 00:00:00 2001
From: Kaituo Li <kaituo@amazon.com>
Date: Thu, 15 Dec 2022 16:29:45 -0800
Subject: [PATCH] add comment and improve logging

Signed-off-by: Kaituo Li <kaituo@amazon.com>
---
 .../ad/ExecuteADResultResponseRecorder.java          | 12 +++++++++++-
 .../ad/ratelimit/EntityColdStartWorker.java          |  8 +++++++-
 .../IndexAnomalyDetectorJobActionHandler.java        |  2 ++
 3 files changed, 20 insertions(+), 2 deletions(-)

diff --git a/src/main/java/org/opensearch/ad/ExecuteADResultResponseRecorder.java b/src/main/java/org/opensearch/ad/ExecuteADResultResponseRecorder.java
index 721eeb898..19710f0cb 100644
--- a/src/main/java/org/opensearch/ad/ExecuteADResultResponseRecorder.java
+++ b/src/main/java/org/opensearch/ad/ExecuteADResultResponseRecorder.java
@@ -208,6 +208,16 @@ private void updateLatestRealtimeTask(
             );
     }
 
+    /**
+     * The function is not only indexing the result with the exception, but also updating the task state after
+     * 60s if the exception is related to cold start (index not found exceptions) for a single stream detector.
+     *
+     * @param detectionStartTime execution start time
+     * @param executionStartTime execution end time
+     * @param errorMessage Error message to record
+     * @param taskState AD task state (e.g., stopped)
+     * @param detector Detector config accessor
+     */
     public void indexAnomalyResultException(
         Instant detectionStartTime,
         Instant executionStartTime,
@@ -262,7 +272,7 @@ public void indexAnomalyResultException(
                             totalUpdates > 0 ? "" : errorMessage
                         );
                     }, e -> {
-                        log.error("Fail to eecute RCFRollingAction", e);
+                        log.error("Fail to execute RCFRollingAction", e);
                         updateLatestRealtimeTask(detectorId, taskState, null, null, errorMessage);
                     }));
                 }, new TimeValue(60, TimeUnit.SECONDS), AnomalyDetectorPlugin.AD_THREAD_POOL_NAME);
diff --git a/src/main/java/org/opensearch/ad/ratelimit/EntityColdStartWorker.java b/src/main/java/org/opensearch/ad/ratelimit/EntityColdStartWorker.java
index b02ad314b..8702fafcc 100644
--- a/src/main/java/org/opensearch/ad/ratelimit/EntityColdStartWorker.java
+++ b/src/main/java/org/opensearch/ad/ratelimit/EntityColdStartWorker.java
@@ -124,7 +124,13 @@ protected void executeRequest(EntityRequest coldStartRequest, ActionListener<Voi
             nodeStateManager.getAnomalyDetector(detectorId, ActionListener.wrap(detectorOptional -> {
                 try {
                     if (!detectorOptional.isPresent()) {
-                        LOG.error(new ParameterizedMessage("fail to get detector [{}]", detectorId));
+                        LOG
+                            .error(
+                                new ParameterizedMessage(
+                                    "fail to load trained model [{}] to cache due to the detector not being found.",
+                                    modelState.getModelId()
+                                )
+                            );
                         return;
                     }
                     AnomalyDetector detector = detectorOptional.get();
diff --git a/src/main/java/org/opensearch/ad/rest/handler/IndexAnomalyDetectorJobActionHandler.java b/src/main/java/org/opensearch/ad/rest/handler/IndexAnomalyDetectorJobActionHandler.java
index 2b91a0a06..31256f3ed 100644
--- a/src/main/java/org/opensearch/ad/rest/handler/IndexAnomalyDetectorJobActionHandler.java
+++ b/src/main/java/org/opensearch/ad/rest/handler/IndexAnomalyDetectorJobActionHandler.java
@@ -121,6 +121,8 @@ public IndexAnomalyDetectorJobActionHandler(
      * @param listener Listener to send responses
      */
     public void startAnomalyDetectorJob(AnomalyDetector detector, ActionListener<AnomalyDetectorJobResponse> listener) {
+        // this start listener is created & injected throughout the job handler so that whenever the job response is received,
+        // there's the extra step of trying to index results and update detector state with a 60s delay.
         ActionListener<AnomalyDetectorJobResponse> startListener = ActionListener.wrap(r -> {
             try {
                 Instant executionEndTime = Instant.now();