Use 2 instead of 1 nested query to lookup the historic entity links w…

…ith same root scope by scopeIds The reason for using 2 queries is due to the fact that some DBs are going to do a full table scan if we nest the queries into a single query
filiphr · Apr 24, 2023 · 24fff39 · 24fff39
1 parent d002b0b
commit 24fff39
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Showing 2 changed files with 40 additions and 17 deletions.
diff --git a/...ylink/service/impl/persistence/entity/data/impl/MybatisHistoricEntityLinkDataManager.java b/...ylink/service/impl/persistence/entity/data/impl/MybatisHistoricEntityLinkDataManager.java
@@ -12,6 +12,7 @@
  */
 package org.flowable.entitylink.service.impl.persistence.entity.data.impl;
 
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashMap;
 import java.util.List;
@@ -76,12 +77,21 @@ public List<HistoricEntityLink> findHistoricEntityLinksWithSameRootScopeForScope
     @Override
     @SuppressWarnings({ "rawtypes", "unchecked" })
     public List<HistoricEntityLink> findHistoricEntityLinksWithSameRootScopeForScopeIdsAndScopeType(Collection<String> scopeIds, String scopeType, String linkType) {
+        // We are using 2 queries here (first find all the root scope ids and then find all the entity links for those root scope ids)
+        // The reason for using 2 queries is due to the fact that some DBs are going to do a full table scan if we nest the queries into a single query
         Map<String, Object> parameters = new HashMap<>();
         parameters.put("scopeIds", createSafeInValuesList(scopeIds));
         parameters.put("scopeType", scopeType);
         parameters.put("linkType", linkType);
-
-        return (List) getList("selectHistoricEntityLinksWithSameRootScopeByScopeIdsAndType", parameters);
+        List rootScopeIds = getDbSqlSession().selectList("selectRootScopeIdsByScopeIdsAndType", parameters);
+        if (rootScopeIds.isEmpty()) {
+            return new ArrayList<>();
+        }
+
+        parameters.put("rootScopeIds", createSafeInValuesList(rootScopeIds));
+        parameters.remove("scopeIds");
+
+        return (List) getList("selectHistoricEntityLinksByRootScopeIdsAndType", parameters);
     }
 
     @SuppressWarnings({ "rawtypes", "unchecked" })

diff --git a/...c/main/resources/org/flowable/entitylink/service/db/mapping/entity/HistoricEntityLink.xml b/...c/main/resources/org/flowable/entitylink/service/db/mapping/entity/HistoricEntityLink.xml
@@ -192,23 +192,36 @@
     where LINK_TYPE_ = #{parameter.linkType}
   </select>
 
-  <select id="selectHistoricEntityLinksWithSameRootScopeByScopeIdsAndType" resultMap="historicEntityLinkResultMap">
+  <select id="selectHistoricEntityLinksByRootScopeIdsAndType" resultMap="historicEntityLinkResultMap">
     select RES.*
-    from ${prefix}ACT_HI_ENTITYLINK RES where ROOT_SCOPE_ID_ in (
-        select ROOT_SCOPE_ID_ from ${prefix}ACT_HI_ENTITYLINK
-        where 
-        (<foreach item="listItem" index="listIndex" collection="parameter.scopeIds">
-            <if test="listIndex &gt; 0">
-            or
-            </if>
-            SCOPE_ID_ in 
-            <foreach item="item" index="index" collection="listItem" open="(" separator="," close=")">
-              #{item}
-            </foreach>
-        </foreach>)
-        and SCOPE_TYPE_ = #{parameter.scopeType} and LINK_TYPE_ = #{parameter.linkType} and ROOT_SCOPE_ID_ is not null
-    ) 
+    from ${prefix}ACT_HI_ENTITYLINK RES where (
+    <foreach item="listItem" index="listIndex" collection="parameter.rootScopeIds">
+        <if test="listIndex &gt; 0">
+        or
+        </if>
+        ROOT_SCOPE_ID_ in
+        <foreach item="item" index="index" collection="listItem" open="(" separator="," close=")">
+          #{item}
+        </foreach>
+    </foreach>
+    )
     and LINK_TYPE_ = #{parameter.linkType}
   </select>
 
+  <select id="selectRootScopeIdsByScopeIdsAndType" resultType="string">
+    select distinct ROOT_SCOPE_ID_
+    from ${prefix}ACT_HI_ENTITYLINK
+    where
+    (<foreach item="listItem" index="listIndex" collection="parameter.scopeIds">
+        <if test="listIndex &gt; 0">
+        or
+        </if>
+        SCOPE_ID_ in
+        <foreach item="item" index="index" collection="listItem" open="(" separator="," close=")">
+          #{item}
+        </foreach>
+    </foreach>)
+    and SCOPE_TYPE_ = #{parameter.scopeType} and LINK_TYPE_ = #{parameter.linkType} and ROOT_SCOPE_ID_ is not null
+  </select>
+
 </mapper>