[jira] [Assigned] (PHOENIX-3133) Investigate why offset queries with reverse scan take a long time

["Ankit Singhal (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/PHOENIX-3133?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Ankit Singhal reassigned PHOENIX-3133:
--------------------------------------

    Assignee: Ankit Singhal

> Investigate why offset queries with reverse scan take a long time
> -----------------------------------------------------------------
>
>                 Key: PHOENIX-3133
>                 URL: https://issues.apache.org/jira/browse/PHOENIX-3133
>             Project: Phoenix
>          Issue Type: Bug
>            Reporter: Samarth Jain
>            Assignee: Ankit Singhal
>             Fix For: 4.8.1
>
>
> We need to workaround HBASE-16296 because users of Phoenix won't see the fix until at least the fix makes it into a release version of HBase. Unfortunately, often times users are forced to stick to earlier version of HBase, even after a release. PHOENIX-3121 works around the issue when there's only a LIMIT clause. However, if there's a LIMIT and an OFFSET, the issue still occurs. 
> Repro code courtesy, [~mujtabachohan] 
> {code}
> DDL:
> CREATE TABLE IF NOT EXISTS XYZ.T (
> 		TENANT_ID CHAR(15) NOT NULL, 
> 		KEY_PREFIX CHAR(3) NOT NULL,
> 		CREATED_DATE DATE,
> 		CREATED_BY CHAR(15),
> 		LAST_UPDATE DATE,
> 		LAST_UPDATE_BY CHAR(15),
> 		SYSTEM_MODSTAMP DATE
> 		CONSTRAINT PK PRIMARY KEY (
> 		TENANT_ID, 
> 		KEY_PREFIX
> 		)
> 		) VERSIONS=1, IMMUTABLE_ROWS=true, MULTI_TENANT=true, REPLICATION_SCOPE=1
> 		
> 		CREATE VIEW IF NOT EXISTS XYZ.ABC_VIEW (
> 		ACTIVITY_DATE DATE NOT NULL,
> 		WHO_ID CHAR(15) NOT NULL,
> 		WHAT_ID CHAR(15) NOT NULL,
> 		CHANNEL_TYPE VARCHAR NOT NULL,
> 		CHANNEL_ACTION_TYPE VARCHAR NOT NULL,
> 		ENGAGEMENT_HISTORY_POC_ID CHAR(15) ,
> 		CHANNEL_CONTEXT VARCHAR
> 		CONSTRAINT PKVIEW PRIMARY KEY
> 		(
> 		ACTIVITY_DATE, WHO_ID, WHAT_ID, CHANNEL_TYPE, CHANNEL_ACTION_TYPE
> 		)
> 		)
> 		AS SELECT * FROM XYZ.T WHERE KEY_PREFIX = '08m' 
> UPSERT records using this:
> Connection con = DriverManager.getConnection("jdbc:phoenix:samarthjai-ltm3.internal.salesforce.com", new Properties());
> 		PreparedStatement pStatement;
> 		pStatement = con.prepareStatement("upsert into XYZ.ABC_VIEW (ACTIVITY_DATE,CHANNEL_ACTION_TYPE,CHANNEL_TYPE,TENANT_ID,WHAT_ID,WHO_ID) values (TO_DATE('2010-11-11 00:00:00.000'),?,'ABC','00Dx0000000GyYS','701x00000000dzp','00Qx0000001S2qa')");
> 		for (int i=0; i<10000000;i++) {
> 			pStatement.setString(1, UUID.randomUUID().toString());
> 			pStatement.execute();
> 			
> 			if (i % 10000 == 0) {
> 				con.commit();
> 				System.out.println(i);
> 			}
> 		}
> Sample query:
> @Test
>     public void testLimitCacheQuery() throws Exception {
>         String url = "jdbc:phoenix:localhost:2181";
>         try (Connection conn = DriverManager.getConnection(url)) {
>             PreparedStatement stmt = conn.prepareStatement("select * from XYZ.ABC_VIEW where who_id = '00Qx0000001S2qa' and TENANT_ID='00Dx0000000GyYS' order by activity_date desc LIMIT 18 OFFSET 2");
>             stmt.setFetchSize(10);
>             try (ResultSet rs = stmt.executeQuery()) {
>                 long startTime = System.currentTimeMillis();
>                 int record = 0;
>                 while (rs.next()) {
>                     System.out.println("Record "+ (++record) + " Time: " + (System.currentTimeMillis() - startTime));
>                     startTime = System.currentTimeMillis();
>                 }
>             }
>         }
>     }
> {code}



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