From 7f22fa32abcee527e21a99b2405f5e22b7e3635c Mon Sep 17 00:00:00 2001
From: Pete Gillin <pete.gillin@elastic.co>
Date: Fri, 4 Apr 2025 19:11:56 +0100
Subject: [PATCH 1/2] Tweak wording of autosharding logs

---
 .../autosharding/DataStreamAutoShardingService.java  | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/server/src/main/java/org/elasticsearch/action/datastreams/autosharding/DataStreamAutoShardingService.java b/server/src/main/java/org/elasticsearch/action/datastreams/autosharding/DataStreamAutoShardingService.java
index d4b2a46b73e6d..bc3798000b67d 100644
--- a/server/src/main/java/org/elasticsearch/action/datastreams/autosharding/DataStreamAutoShardingService.java
+++ b/server/src/main/java/org/elasticsearch/action/datastreams/autosharding/DataStreamAutoShardingService.java
@@ -313,7 +313,7 @@ public String toString() {
             return Strings.format(
                 "For data stream %s: %s based on [inc/dec cooldowns %s/%s, %d-%d threads, "
                     + "write index %s has all-time/recent/peak loads %g/%g/%g, current shards %d, "
-                    + "using %s value %g for increase gives %d shards%s]",
+                    + "increase calculation gives %d shards using %s load %g for write index%s]",
                 inputs.dataStream,
                 result,
                 inputs.increaseShardsCooldown,
@@ -325,19 +325,19 @@ public String toString() {
                 inputs.writeIndexRecentLoad,
                 inputs.writeIndexPeakLoad,
                 inputs.currentNumberOfWriteIndexShards,
+                increaseCalculation.optimalShardCountForIncrease,
                 inputs.increaseShardsMetric,
                 increaseCalculation.writeIndexLoadForIncrease,
-                increaseCalculation.optimalShardCountForIncrease,
                 decreaseCalculation == null
                     ? ""
-                    : Strings.format(
-                        ", and using %s value %g for dec based on %s gives %d shards",
+                    : String.format(
+                        ", decrease calculation gives %d shards using %s load %g for %s",
+                        decreaseCalculation.optimalShardCountForDecrease,
                         inputs.decreaseShardsMetric,
                         decreaseCalculation.maxLoadWithinCooldown.load,
                         decreaseCalculation.maxLoadWithinCooldown.previousIndexWithMaxLoad != null
                             ? decreaseCalculation.maxLoadWithinCooldown.previousIndexWithMaxLoad
-                            : "write index",
-                        decreaseCalculation.optimalShardCountForDecrease
+                            : "write index"
                     )
             );
         }

From d90523ef264378a27cfbe3840f8aa280f6ade3ef Mon Sep 17 00:00:00 2001
From: Pete Gillin <pete.gillin@elastic.co>
Date: Mon, 7 Apr 2025 11:24:54 +0100
Subject: [PATCH 2/2] Use correct `Strings.format`

---
 .../datastreams/autosharding/DataStreamAutoShardingService.java | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/server/src/main/java/org/elasticsearch/action/datastreams/autosharding/DataStreamAutoShardingService.java b/server/src/main/java/org/elasticsearch/action/datastreams/autosharding/DataStreamAutoShardingService.java
index bc3798000b67d..72857c8249055 100644
--- a/server/src/main/java/org/elasticsearch/action/datastreams/autosharding/DataStreamAutoShardingService.java
+++ b/server/src/main/java/org/elasticsearch/action/datastreams/autosharding/DataStreamAutoShardingService.java
@@ -330,7 +330,7 @@ public String toString() {
                 increaseCalculation.writeIndexLoadForIncrease,
                 decreaseCalculation == null
                     ? ""
-                    : String.format(
+                    : Strings.format(
                         ", decrease calculation gives %d shards using %s load %g for %s",
                         decreaseCalculation.optimalShardCountForDecrease,
                         inputs.decreaseShardsMetric,