From ce000fda5bc550b83241489818a2ce9dd657470e Mon Sep 17 00:00:00 2001
From: "yaqian.zhang" <598593183@qq.com>
Date: Mon, 13 Jan 2020 17:36:35 +0800
Subject: [PATCH] KYLIN-4291 Parallel segment building may causes
 WriteConflictException

---
 .../apache/kylin/dict/DictionaryManager.java  | 31 +++++++++++++++----
 .../kylin/dict/lookup/SnapshotManager.java    | 20 ++++++++++--
 2 files changed, 42 insertions(+), 9 deletions(-)

diff --git a/core-dictionary/src/main/java/org/apache/kylin/dict/DictionaryManager.java b/core-dictionary/src/main/java/org/apache/kylin/dict/DictionaryManager.java
index ffee105c7ff..6b23a9ec51a 100755
--- a/core-dictionary/src/main/java/org/apache/kylin/dict/DictionaryManager.java
+++ b/core-dictionary/src/main/java/org/apache/kylin/dict/DictionaryManager.java
@@ -27,6 +27,7 @@
 import org.apache.commons.lang3.StringUtils;
 import org.apache.kylin.common.KylinConfig;
 import org.apache.kylin.common.persistence.ResourceStore;
+import org.apache.kylin.common.persistence.WriteConflictException;
 import org.apache.kylin.common.util.ClassUtil;
 import org.apache.kylin.common.util.Dictionary;
 import org.apache.kylin.common.util.JsonUtil;
@@ -193,12 +194,24 @@ private DictionaryInfo updateExistingDictLastModifiedTime(String dictPath) throw
         ResourceStore store = getStore();
         if (StringUtils.isBlank(dictPath))
             return NONE_INDICATOR;
-        long now = System.currentTimeMillis();
-        store.updateTimestamp(dictPath, now);
-        logger.info("Update dictionary {} lastModifiedTime to {}", dictPath, now);
-        DictionaryInfo dictInfo = load(dictPath, true);
-        updateDictCache(dictInfo);
-        return dictInfo;
+
+        int retry = 7;
+        while (retry-- > 0) {
+            try {
+                long now = System.currentTimeMillis();
+                store.updateTimestamp(dictPath, now);
+                logger.info("Update dictionary {} lastModifiedTime to {}", dictPath, now);
+                return loadAndUpdateLocalCache(dictPath);
+            } catch (WriteConflictException e) {
+                if (retry <= 0) {
+                    logger.error("Retry is out, till got error, abandoning...", e);
+                    throw e;
+                }
+                logger.warn("Write conflict to update dictionary " + dictPath + " retry remaining " + retry
+                        + ", will retry...");
+            }
+        }
+        return loadAndUpdateLocalCache(dictPath);
     }
 
     private void initDictInfo(Dictionary<String> newDict, DictionaryInfo newDictInfo) {
@@ -411,6 +424,12 @@ void save(DictionaryInfo dict) throws IOException {
         store.putBigResource(path, dict, System.currentTimeMillis(), DictionaryInfoSerializer.FULL_SERIALIZER);
     }
 
+    private DictionaryInfo loadAndUpdateLocalCache(String dictPath) throws IOException {
+        DictionaryInfo dictInfo = load(dictPath, true);
+        updateDictCache(dictInfo);
+        return dictInfo;
+    }
+
     DictionaryInfo load(String resourcePath, boolean loadDictObj) throws IOException {
         ResourceStore store = getStore();
 
diff --git a/core-dictionary/src/main/java/org/apache/kylin/dict/lookup/SnapshotManager.java b/core-dictionary/src/main/java/org/apache/kylin/dict/lookup/SnapshotManager.java
index 76a3df9a1f1..9d591b503a9 100644
--- a/core-dictionary/src/main/java/org/apache/kylin/dict/lookup/SnapshotManager.java
+++ b/core-dictionary/src/main/java/org/apache/kylin/dict/lookup/SnapshotManager.java
@@ -27,6 +27,7 @@
 
 import org.apache.kylin.common.KylinConfig;
 import org.apache.kylin.common.persistence.ResourceStore;
+import org.apache.kylin.common.persistence.WriteConflictException;
 import org.apache.kylin.metadata.TableMetadataManager;
 import org.apache.kylin.metadata.model.TableDesc;
 import org.apache.kylin.source.IReadableTable;
@@ -236,10 +237,23 @@ private String checkDupByContent(SnapshotTable snapshot) throws IOException {
 
     private SnapshotTable updateDictLastModifiedTime(String snapshotPath) throws IOException {
         ResourceStore store = getStore();
-        long now = System.currentTimeMillis();
-        store.updateTimestamp(snapshotPath, now);
-        logger.info("Update snapshotTable {} lastModifiedTime to {}", snapshotPath, now);
 
+        int retry = 7;
+        while (retry-- > 0) {
+            try {
+                long now = System.currentTimeMillis();
+                store.updateTimestamp(snapshotPath, now);
+                logger.info("Update snapshotTable {} lastModifiedTime to {}", snapshotPath, now);
+                return loadAndUpdateLocalCache(snapshotPath);
+            } catch (WriteConflictException e) {
+                if (retry <= 0) {
+                    logger.error("Retry is out, till got error, abandoning...", e);
+                    throw e;
+                }
+                logger.warn("Write conflict to update snapshotTable " +  snapshotPath + " retry remaining " + retry
+                        + ", will retry...");
+            }
+        }
         // update cache
         return loadAndUpdateLocalCache(snapshotPath);
     }