From 6ed6ce2deb900cec7633858f08e5769e06569e7b Mon Sep 17 00:00:00 2001
From: Jason McKenzie <v-mckenziej@microsoft.com>
Date: Fri, 29 May 2026 13:08:00 -0700
Subject: [PATCH] adjust logging to avoid expensive
 CosmosException.getMessage() on WARN level

---
 .../epkversion/PartitionProcessorImpl.java        | 14 +++++++++++---
 .../pkversion/PartitionProcessorImpl.java         | 15 ++++++++++++---
 2 files changed, 23 insertions(+), 6 deletions(-)

diff --git a/sdk/cosmos/azure-cosmos/src/main/java/com/azure/cosmos/implementation/changefeed/epkversion/PartitionProcessorImpl.java b/sdk/cosmos/azure-cosmos/src/main/java/com/azure/cosmos/implementation/changefeed/epkversion/PartitionProcessorImpl.java
index 8baff17be50b..96d2af4605c6 100644
--- a/sdk/cosmos/azure-cosmos/src/main/java/com/azure/cosmos/implementation/changefeed/epkversion/PartitionProcessorImpl.java
+++ b/sdk/cosmos/azure-cosmos/src/main/java/com/azure/cosmos/implementation/changefeed/epkversion/PartitionProcessorImpl.java
@@ -198,9 +198,17 @@ public Mono<Void> run(CancellationToken cancellationToken) {
 
                     CosmosException clientException = (CosmosException) throwable;
                     logger.warn(
-                        "Lease with token " + this.lease.getLeaseToken() + ": CosmosException was thrown from thread " +
-                            Thread.currentThread().getId() + " for lease with owner " + this.lease.getOwner(),
-                        clientException);
+                        "Lease with token {}: CosmosException was thrown from thread {} for lease with owner {} {}",
+                        this.lease.getLeaseToken(),
+                        Thread.currentThread().getId(),
+                        this.lease.getOwner(),
+                        clientException.getShortMessage());
+                    if (logger.isDebugEnabled()) {
+                        logger.debug(
+                            "Lease with token " + this.lease.getLeaseToken() + ": CosmosException was thrown from thread " +
+                                Thread.currentThread().getId() + " for lease with owner " + this.lease.getOwner(),
+                            clientException);
+                    }
                     StatusCodeErrorType docDbError =
                         ExceptionClassifier.classifyClientException(clientException);
 
diff --git a/sdk/cosmos/azure-cosmos/src/main/java/com/azure/cosmos/implementation/changefeed/pkversion/PartitionProcessorImpl.java b/sdk/cosmos/azure-cosmos/src/main/java/com/azure/cosmos/implementation/changefeed/pkversion/PartitionProcessorImpl.java
index fe1609c3a852..c8f1969f22d2 100644
--- a/sdk/cosmos/azure-cosmos/src/main/java/com/azure/cosmos/implementation/changefeed/pkversion/PartitionProcessorImpl.java
+++ b/sdk/cosmos/azure-cosmos/src/main/java/com/azure/cosmos/implementation/changefeed/pkversion/PartitionProcessorImpl.java
@@ -208,9 +208,18 @@ public Mono<Void> run(CancellationToken cancellationToken) {
                     // we know it is a terminal event.
 
                     CosmosException clientException = (CosmosException) throwable;
-                    logger.warn("CosmosException: Partition " + this.lease.getLeaseToken()
-                            + " from thread " + Thread.currentThread().getId() + " with owner " + this.lease.getOwner(),
-                        clientException);
+                    logger.warn(
+                        "CosmosException: partition {} from thread {} with owner {} {}",
+                        this.lease.getLeaseToken(),
+                        Thread.currentThread().getId(),
+                        this.lease.getOwner(),
+                        clientException.getShortMessage());
+                    if (logger.isDebugEnabled()) {
+                        logger.debug(
+                            "CosmosException: partition" + this.lease.getLeaseToken()
+                                + "from thread " + Thread.currentThread().getId() + " with owner " + this.lease.getOwner(),
+                            clientException);
+                    }
                     StatusCodeErrorType docDbError = ExceptionClassifier.classifyClientException(clientException);
 
                     switch (docDbError) {