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From Maryann Xue <maryann....@gmail.com>
Subject Re: SORT_MERGE_JOIN on non-leading key: server-side sorting
Date Thu, 17 May 2018 23:44:50 GMT
Hey, this is a simple experiment I did based on an existing test case. Look
for "query3". The test verifies that there is no "SERVER SORT" in the
entire query plan (both salted and unsalted tables have been covered):


@Test
public void testBug4508() throws Exception {
    Properties props = PropertiesUtil.deepCopy(TEST_PROPERTIES);
    Connection conn = DriverManager.getConnection(getUrl(), props);
    props = PropertiesUtil.deepCopy(TEST_PROPERTIES);
    props.setProperty("TenantId", "010");
    Connection conn010 = DriverManager.getConnection(getUrl(), props);
    try {
        // Salted tables
        String peopleTable = generateUniqueName();
        String myTable = generateUniqueName();
        conn.createStatement().execute("CREATE TABLE " + peopleTable + " (\n" +
                "PERSON_ID VARCHAR NOT NULL,\n" +
                "NAME VARCHAR\n" +
                "CONSTRAINT PK_TEST_PEOPLE PRIMARY KEY (PERSON_ID))
SALT_BUCKETS = 3");
        conn.createStatement().execute("CREATE TABLE " + myTable + " (\n" +
                "LOCALID VARCHAR NOT NULL,\n" +
                "DSID VARCHAR(255) NOT NULL, \n" +
                "EID CHAR(40),\n" +
                "HAS_CANDIDATES BOOLEAN\n" +
                "CONSTRAINT PK_MYTABLE PRIMARY KEY (LOCALID, DSID))
SALT_BUCKETS = 3");
        verifyQueryPlanAndResultForBug4508(conn, peopleTable, myTable);

        // Salted multi-tenant tables
        String peopleTable2 = generateUniqueName();
        String myTable2 = generateUniqueName();
        conn.createStatement().execute("CREATE TABLE " + peopleTable2 + " (\n" +
                "TENANT_ID VARCHAR NOT NULL,\n" +
                "PERSON_ID VARCHAR NOT NULL,\n" +
                "NAME VARCHAR\n" +
                "CONSTRAINT PK_TEST_PEOPLE PRIMARY KEY (TENANT_ID,
PERSON_ID))\n" +
                "SALT_BUCKETS = 3, MULTI_TENANT=true");
        conn.createStatement().execute("CREATE TABLE " + myTable2 + " (\n" +
                "TENANT_ID VARCHAR NOT NULL,\n" +
                "LOCALID VARCHAR NOT NULL,\n" +
                "DSID VARCHAR(255) NOT NULL, \n" +
                "EID CHAR(40),\n" +
                "HAS_CANDIDATES BOOLEAN\n" +
                "CONSTRAINT PK_MYTABLE PRIMARY KEY (TENANT_ID,
LOCALID, DSID))\n" +
                "SALT_BUCKETS = 3, MULTI_TENANT=true");
        verifyQueryPlanAndResultForBug4508(conn010, peopleTable2, myTable2);
    } finally {
        conn.close();
        conn010.close();
    }
}


private static void verifyQueryPlanAndResultForBug4508(
Connection conn, String peopleTable, String myTable) throws Exception {
PreparedStatement peopleTableUpsertStmt = conn.prepareStatement(
"UPSERT INTO " + peopleTable + " VALUES(?, ?)");
peopleTableUpsertStmt.setString(1, "X001");
peopleTableUpsertStmt.setString(2, "Marcus");
peopleTableUpsertStmt.execute();
peopleTableUpsertStmt.setString(1, "X002");
peopleTableUpsertStmt.setString(2, "Jenny");
peopleTableUpsertStmt.execute();
peopleTableUpsertStmt.setString(1, "X003");
peopleTableUpsertStmt.setString(2, "Seymour");
peopleTableUpsertStmt.execute();
conn.commit();

PreparedStatement myTableUpsertStmt = conn.prepareStatement(
"UPSERT INTO " + myTable + " VALUES(?, ?, ?, ?)");
myTableUpsertStmt.setString(1, "X001");
myTableUpsertStmt.setString(2, "GROUP");
myTableUpsertStmt.setString(3, null);
myTableUpsertStmt.setBoolean(4, false);
myTableUpsertStmt.execute();
myTableUpsertStmt.setString(1, "X001");
myTableUpsertStmt.setString(2, "PEOPLE");
myTableUpsertStmt.setString(3, null);
myTableUpsertStmt.setBoolean(4, false);
myTableUpsertStmt.execute();
myTableUpsertStmt.setString(1, "X003");
myTableUpsertStmt.setString(2, "PEOPLE");
myTableUpsertStmt.setString(3, null);
myTableUpsertStmt.setBoolean(4, false);
myTableUpsertStmt.execute();
myTableUpsertStmt.setString(1, "X002");
myTableUpsertStmt.setString(2, "PEOPLE");
myTableUpsertStmt.setString(3, "Z990");
myTableUpsertStmt.setBoolean(4, false);
myTableUpsertStmt.execute();
conn.commit();

String query1 = "SELECT /*+ USE_SORT_MERGE_JOIN*/ COUNT(*)\n" +
"FROM " + peopleTable + " ds JOIN " + myTable + " l\n" +
"ON ds.PERSON_ID = l.LOCALID\n" +
"WHERE l.EID IS NULL AND l.DSID = 'PEOPLE' AND l.HAS_CANDIDATES = FALSE";
String query2 = "SELECT /*+ USE_SORT_MERGE_JOIN */ COUNT(*)\n" +
"FROM (SELECT LOCALID FROM " + myTable + "\n" +
"WHERE EID IS NULL AND DSID = 'PEOPLE' AND HAS_CANDIDATES = FALSE) l\n" +
"JOIN " + peopleTable + " ds ON ds.PERSON_ID = l.LOCALID";
String query3 = "SELECT /*+ USE_SORT_MERGE_JOIN */ COUNT(*)\n" +
"FROM " + myTable + " t1 JOIN " + myTable + " t2\n" +
"ON t1.DSID = t2.DSID\n" +
"WHERE t1.LOCALID = 'X001' AND t2.LOCALID = 'X002'";

for (String q : new String[]{query1, query2, query3}) {
ResultSet rs = conn.createStatement().executeQuery("explain " + q);
String plan = QueryUtil.getExplainPlan(rs);
assertFalse("Tables should not be sorted over their PKs:\n" + plan,
plan.contains("SERVER SORTED BY"));

rs = conn.createStatement().executeQuery(q);
assertTrue(rs.next());
//assertEquals(2, rs.getInt(1));
assertFalse(rs.next());
}
}



On Thu, May 17, 2018 at 3:48 PM, Gerald Sangudi <gsangudi@23andme.com>
wrote:

> Hi Maryann,
>
> Would you mind sharing the EXPLAIN output you are getting?
>
> I'm not able to find a download for phoenix-4.13.2-HBase or 4.14.0-HBase.
> The *-cdh downloads do not work with Amazon EMR. I tried building against
> the 4.14.0-rc0 tag. This produced 4.14.0 for phoenix-core.jar, but all the
> other jars produced are 4.13.1, including the client jar. When I deploy
> these jars on EMR and run queries via sqlline, I get a NoClassDefFoundError.
>
> Are the plans to provide 4.13.2-HBase as a public download?
>
> Thanks,
> Gerald
>
> On Wed, May 16, 2018 at 10:40 AM, Maryann Xue <maryann.xue@gmail.com>
> wrote:
>
>> Hi Gerald,
>>
>> I checked again. Unfortunately this fix is included with 4.13.2 but not
>> 4.13.1. Would you mind upgrading your library to 4.13.2?
>>
>> Thanks,
>> Maryann
>>
>> On Wed, May 16, 2018 at 9:41 AM, Maryann Xue <maryann.xue@gmail.com>
>> wrote:
>>
>>> Sorry for the late response. Yes, sure, I will try it right away.
>>>
>>> On Wed, May 16, 2018 at 9:40 AM Gerald Sangudi <gsangudi@23andme.com>
>>> wrote:
>>>
>>>> Hi Maryann,
>>>>
>>>> Following up again -- I ran EXPLAIN on 4.13.1 and saw the same
>>>> behavior, a sort on the RHS. Is it possible for you to try it on 4.13.1?
>>>>
>>>> Thanks,
>>>> Gerald
>>>>
>>>> On Fri, May 11, 2018 at 10:52 AM, Gerald Sangudi <gsangudi@23andme.com>
>>>> wrote:
>>>>
>>>>> Hi Maryann,
>>>>>
>>>>> Thanks for verifying against latest. However, I did not detect the fix
>>>>> in Phoenix 4.13.1. AWS EMR currently provides Phoenix 4.13.0. I manually
>>>>> upgraded an AWS EMR cluster to Phoenix 4.13.1 and rebooted the cluster.
The
>>>>> EXPLAIN plan still shows the same issue.
>>>>>
>>>>> Thanks,
>>>>> Gerald
>>>>>
>>>>> On Wed, May 9, 2018 at 11:51 AM, Maryann Xue <maryann.xue@gmail.com>
>>>>> wrote:
>>>>>
>>>>>> Hi Gerald,
>>>>>>
>>>>>> I have verified against latest Phoenix code that this problem has
>>>>>> been fixed. I have also checked Phoenix 4.13 release tags. Looks
like all
>>>>>> versions of 4.13 packages now include that fix. Would you mind getting
the
>>>>>> latest Phoenix-4.13 package and testing it again? Thank you!
>>>>>>
>>>>>>
>>>>>> Thanks,
>>>>>> Maryann
>>>>>>
>>>>>> On Tue, May 8, 2018 at 12:24 PM, Gerald Sangudi <gsangudi@23andme.com
>>>>>> > wrote:
>>>>>>
>>>>>>> Hello,
>>>>>>>
>>>>>>> I'm running Phoenix 4.13 on AWS EMR and getting the following
>>>>>>> EXPLAIN plan:
>>>>>>>
>>>>>>> Table:
>>>>>>>
>>>>>>> *CREATE TABLE salted (       keyA BIGINT NOT NULL,       keyB
BIGINT
>>>>>>> NOT NULL,       val SMALLINT,       CONSTRAINT pk PRIMARY KEY
(keyA,
>>>>>>> keyB))SALT_BUCKETS = 64;*
>>>>>>> EXPLAIN:
>>>>>>>
>>>>>>> *EXPLAINSELECT /*+ USE_SORT_MERGE_JOIN */COUNT(*) cFROM salted
t1
>>>>>>> JOIN salted t2ON (t1.keyB = t2.keyB)WHERE t1.keyA = 10AND t2.keyA
= 20;*
>>>>>>>
>>>>>>> *+------------------------------------------------------------------------------+-----------------+-+|
>>>>>>>                                     PLAN   | EST_BYTES_READ |
>>>>>>> |+------------------------------------------------------------------------------+-----------------+-+|
>>>>>>> SORT-MERGE-JOIN (INNER) TABLES
>>>>>>>                                               | null | ||   
 CLIENT
>>>>>>> 64-CHUNK PARALLEL 64-WAY RANGE SCAN OVER SALTED [0,10] - [63,10]
 | null |
>>>>>>> ||         SERVER FILTER BY FIRST KEY ONLY
>>>>>>>                                      | null | ||     CLIENT MERGE
SORT
>>>>>>>                                                        | null
| || AND
>>>>>>> (SKIP MERGE)                                                
            |
>>>>>>> null | ||     CLIENT 64-CHUNK PARALLEL 64-WAY RANGE SCAN OVER
SALTED [0,20]
>>>>>>> - [63,20]  | null | ||         SERVER FILTER BY FIRST KEY ONLY
>>>>>>>                                      | null | ||         SERVER
SORTED BY
>>>>>>> [T2.KEYB]                                           | null |
||     CLIENT
>>>>>>> MERGE SORT                                                  
     | null |
>>>>>>> || CLIENT AGGREGATE INTO SINGLE ROW
>>>>>>>                                             | null |
>>>>>>> |+------------------------------------------------------------------------------+-----------------+-+*
>>>>>>>
>>>>>>> In the EXPLAIN output, I see "SERVER SORTED BY [T2.KEYB]". Is
this
>>>>>>> sort necessary? For both JOIN terms T1 and T2, the value of keyA,
the
>>>>>>> leading part of the primary key, is fixed. Furthermore, there
is no
>>>>>>> corresponding sort of T1.KEYB.
>>>>>>>
>>>>>>> When I EXPLAIN the same query on a non-salted table, neither
T1.KEYB
>>>>>>> nor T2.KEYB is re-sorted. I'm hoping the sort is unnecessary.
If so, is
>>>>>>> there an open ticket? I would be happy to file a ticket and to
contribute
>>>>>>> to a fix. I would appreciate any guidance.
>>>>>>>
>>>>>>> Thanks,
>>>>>>> Gerald
>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>
>

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