From 36c2e6352d75ff9e95948df2b8892c95118dc929 Mon Sep 17 00:00:00 2001
From: Dongjoon Hyun <dhyun@apple.com>
Date: Thu, 21 Sep 2023 10:08:50 -0700
Subject: [PATCH 1/2] [SPARK-45257][CORE] Enable spark.eventLog.compress by
 default

---
 .../main/scala/org/apache/spark/internal/config/package.scala | 2 +-
 docs/configuration.md                                         | 2 +-
 docs/core-migration-guide.md                                  | 4 ++++
 3 files changed, 6 insertions(+), 2 deletions(-)

diff --git a/core/src/main/scala/org/apache/spark/internal/config/package.scala b/core/src/main/scala/org/apache/spark/internal/config/package.scala
index 05b2624b4037..2dcd3af7a52d 100644
--- a/core/src/main/scala/org/apache/spark/internal/config/package.scala
+++ b/core/src/main/scala/org/apache/spark/internal/config/package.scala
@@ -165,7 +165,7 @@ package object config {
     ConfigBuilder("spark.eventLog.compress")
       .version("1.0.0")
       .booleanConf
-      .createWithDefault(false)
+      .createWithDefault(true)
 
   private[spark] val EVENT_LOG_BLOCK_UPDATES =
     ConfigBuilder("spark.eventLog.logBlockUpdates.enabled")
diff --git a/docs/configuration.md b/docs/configuration.md
index 8fda9317bc77..e9ed2a8aa37d 100644
--- a/docs/configuration.md
+++ b/docs/configuration.md
@@ -1311,7 +1311,7 @@ Apart from these, the following properties are also available, and may be useful
 </tr>
 <tr>
   <td><code>spark.eventLog.compress</code></td>
-  <td>false</td>
+  <td>true</td>
   <td>
     Whether to compress logged events, if <code>spark.eventLog.enabled</code> is true.
   </td>
diff --git a/docs/core-migration-guide.md b/docs/core-migration-guide.md
index 3f97a484e1a6..69f8f6de2147 100644
--- a/docs/core-migration-guide.md
+++ b/docs/core-migration-guide.md
@@ -22,6 +22,10 @@ license: |
 * Table of contents
 {:toc}
 
+## Upgrading from Core 3.4 to 4.0
+
+- Since Spark 4.4, Spark will compress event logs. To restore the behavior before Spark 4.0, you can set `spark.eventLog.compress` to `false`.
+
 ## Upgrading from Core 3.3 to 3.4
 
 - Since Spark 3.4, Spark driver will own `PersistentVolumnClaim`s and try to reuse if they are not assigned to live executors. To restore the behavior before Spark 3.4, you can set `spark.kubernetes.driver.ownPersistentVolumeClaim` to `false` and `spark.kubernetes.driver.reusePersistentVolumeClaim` to `false`.

From b54b7859e1e7c40dc2560ef993055a4ce6a5a852 Mon Sep 17 00:00:00 2001
From: Dongjoon Hyun <dongjoon@apache.org>
Date: Thu, 21 Sep 2023 19:26:11 -0700
Subject: [PATCH 2/2] Update docs/core-migration-guide.md

Co-authored-by: Kent Yao <yao@apache.org>
---
 docs/core-migration-guide.md | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/docs/core-migration-guide.md b/docs/core-migration-guide.md
index 69f8f6de2147..765c3494f669 100644
--- a/docs/core-migration-guide.md
+++ b/docs/core-migration-guide.md
@@ -24,7 +24,7 @@ license: |
 
 ## Upgrading from Core 3.4 to 4.0
 
-- Since Spark 4.4, Spark will compress event logs. To restore the behavior before Spark 4.0, you can set `spark.eventLog.compress` to `false`.
+- Since Spark 4.0, Spark will compress event logs. To restore the behavior before Spark 4.0, you can set `spark.eventLog.compress` to `false`.
 
 ## Upgrading from Core 3.3 to 3.4