Identifying Teradata table skew query

SAMPLE TABLE SKEW IDENTIFYING QUERY:

 Lock Dbc.TableSize For Access 

Lock Dbc.tables For Access 

SELECT B.databasename , B.TableName , A.LastAccessTimeStamp , SUM ( currentperm ) ( NAMED CurrentPerm ) ,

 MAXIMUM ( currentperm ) ( NAMED MaxPerm ) , AVG ( currentperm ) ( NAMED AvgPerm ) ,

 ( ( MAXIMUM ( currentperm ) - AVG ( currentperm ) ) * 100.0 ) / ( MAXIMUM ( currentperm ) ) ( NAMED SkewPercent ) 

FROM dbc.tablesize B INNER JOIN DBC.TABLES A 

 ON A.DATABASENAME = B.DATABASENAME 

 AND A.TABLENAME = B.TABLENAME 

WHERE B.DATABASENAME = <my_database>

GROUP BY 1 , 2 , 3 

HAVING ( ( MAXIMUM ( currentperm ) - AVG ( currentperm ) ) * 100.0 ) / ( MAXIMUM ( currentperm ) ) > 20 

ORDER BY 1 , 2 ;

Teradata fastload sample syntax

LOGON INFO:

.LOGON 127.0.0.1/dbc,dbc 

/* servername/userid,password */

/* if you are using LDAP mechanism then use .logmech ldap before .logon statement for authentication*/

.SESSIONS 4;

.CHECKPOINT 10;  /* When to take checkpoint */

.DATABASE COOKBOOK_FL /* Set default database */

DROP STAGGING AND ERROR TABLE:

DROP TABLE TEST_FL; /*To drop existing staging table*/

DROP TABLE ERR_FL1; /*To Drop error table*/

DROP TABLE ERR_FL2; /*To Drop error table*/

LOAD TABLE:

CREATE MULTISET TABLE TEST_FL ,NO FALLBACK ,NO BEFORE JOURNAL,

NO AFTER JOURNAL,

CHECKSUM = DEFAULT,

DEFAULT MERGEBLOCKRATIO

(

Name VARCHAR(30),

Sr_NAME VARCHAR(30) CHARACTER SET LATIN NOT CASESPECIFIC),

dob date,

Sal Decimal(18,0),

Id INT(2)

)

PRIMARY INDEX ( Name,id );

INPUT FILE DELIMITER:

/*SET RECORD is used to define the delimiter used in file, here | is the delimiter for current flat file*/

SET RECORD VARTEXT “|”;

/*to define the structure of the file use DEFINE and mention 

the file path from which, table will be loaded*/

DEFINE Name (VARCHAR(6))

,Sr_NAME (VARCHAR(20))

,dob (VARCHAR(10))

,Sal (VARCHAR(30))

,ID (VARCHAR(2))

FILE = C:/tmp/accounts_data.txt;  /*flat file path*/

/*BEGIN will start the load process */

BEGIN LOADING TEST_FL

ERRORFILES ERR_FL1,DEV.ERR_FL2;

INSERT INTO TEST_FL

VALUES(:Name,:Sr_NAME,:dob,:Sal,:id);

END LOADING;

LOGOFF; 

/*last statement in the fastload script*/