diff --git a/workflow/engine/config/schema.xml b/workflow/engine/config/schema.xml
index af799202f..f0c301de3 100755
--- a/workflow/engine/config/schema.xml
+++ b/workflow/engine/config/schema.xml
@@ -1290,6 +1290,9 @@
     <column name="TAS_SELFSERVICE_TIME_UNIT" type="VARCHAR" size="15" default=""/>
     <column name="TAS_SELFSERVICE_TRIGGER_UID" type="VARCHAR" size="32" default=""/>
     <column name="TAS_SELFSERVICE_EXECUTION" type="VARCHAR" size="15" default="EVERY_TIME"/>
+    <index name="indexTasUid">
+      <index-column name="TAS_UID"/>
+    </index>
 
     <validator column="TAS_TYPE">
         <rule name="validValues" value="NORMAL|ADHOC|SUBPROCESS|HIDDEN|GATEWAYTOGATEWAY|WEBENTRYEVENT|END-MESSAGE-EVENT|START-MESSAGE-EVENT|INTERMEDIATE-THROW-MESSAGE-EVENT|INTERMEDIATE-CATCH-MESSAGE-EVENT|SCRIPT-TASK|START-TIMER-EVENT|INTERMEDIATE-CATCH-TIMER-EVENT|END-EMAIL-EVENT" message="Please set a valid value for TAS_TYPE" />
@@ -1534,6 +1537,9 @@
     </column>
     <column name="USR_TIME_ZONE" type="VARCHAR" size="100" default="" />
     <column name="USR_DEFAULT_LANG" type="VARCHAR" size="10" default=""/>
+    <index name="indexUsrUid">
+      <index-column name="USR_UID"/>
+    </index>
     <validator column="USR_STATUS">
       <rule name="validValues" value="ACTIVE|INACTIVE|VACATION|CLOSED" message="Please select a valid type."/>
       <rule name="required" message="Type is required."/>
@@ -2513,6 +2519,18 @@
     <column name="APP_FINISH_DATE" type="TIMESTAMP" required="false"/>
     <column name="APP_UPDATE_DATE" type="TIMESTAMP" required="true"/>
     <column name="APP_OVERDUE_PERCENTAGE" type="DOUBLE" required="true"/>
+    <index name="indexAppUid">
+      <index-column name="APP_UID"/>
+    </index>
+    <index name="indexTasUid">
+      <index-column name="TAS_UID"/>
+    </index>
+    <index name="indexUsrUid">
+      <index-column name="USR_UID"/>
+    </index>
+    <index name="indexPrevUsrUid">
+      <index-column name="PREVIOUS_USR_UID"/>
+    </index>
     <index name="indexProUid">
       <index-column name="PRO_UID"/>
       <vendor type="mysql">
diff --git a/workflow/engine/data/mysql/schema.sql b/workflow/engine/data/mysql/schema.sql
index f3077f40b..0f28a08e0 100755
--- a/workflow/engine/data/mysql/schema.sql
+++ b/workflow/engine/data/mysql/schema.sql
@@ -629,7 +629,8 @@ CREATE TABLE `TASK`
 	`TAS_SELFSERVICE_TIME_UNIT` VARCHAR(15) default '',
 	`TAS_SELFSERVICE_TRIGGER_UID` VARCHAR(32) default '',
 	`TAS_SELFSERVICE_EXECUTION` VARCHAR(15) default 'EVERY_TIME',
-	PRIMARY KEY (`TAS_UID`)
+	PRIMARY KEY (`TAS_UID`),
+	KEY `indexTasUid` (`TAS_UID`)
 )ENGINE=InnoDB  DEFAULT CHARSET='utf8' COMMENT='Task of workflow';
 #-----------------------------------------------------------------------------
 #-- TASK_USER
@@ -726,7 +727,8 @@ CREATE TABLE `USERS`
 	`USR_BOOKMARK_START_CASES` MEDIUMTEXT,
 	`USR_TIME_ZONE` VARCHAR(100) default '',
 	`USR_DEFAULT_LANG` VARCHAR(10) default '',
-	PRIMARY KEY (`USR_UID`)
+	PRIMARY KEY (`USR_UID`),
+	KEY `indexUsrUid` (`USR_UID`)
 )ENGINE=InnoDB  DEFAULT CHARSET='utf8' COMMENT='Users';
 #-----------------------------------------------------------------------------
 #-- APP_THREAD
@@ -1194,6 +1196,10 @@ CREATE TABLE `APP_CACHE_VIEW`
 	`APP_UPDATE_DATE` DATETIME  NOT NULL,
 	`APP_OVERDUE_PERCENTAGE` DOUBLE  NOT NULL,
 	PRIMARY KEY (`APP_UID`,`DEL_INDEX`),
+	KEY `indexAppUid`(`APP_UID`),
+	KEY `indexTasUid`(`TAS_UID`),
+	KEY `indexUsrUid`(`USR_UID`),
+	KEY `indexPrevUsrUid`(`PREVIOUS_USR_UID`),
 	KEY `indexProUid`(`PRO_UID`),
 	KEY `indexAppNumber`(`APP_NUMBER`),
 	KEY `protitle`(`APP_PRO_TITLE`),