爲什麼執行「select * from dbc.columnsX」對teradata來說很慢13.10

Question

我在teradata 13.10上執行select * from dbc.columnsX時遇到了一個奇怪的問題。它非常緩慢;但在Teradata 12.0上它速度非常快。對於teradata 13.10，dbc用戶是否缺少一些權利，或者還有其他一些原因導致了這種現象。

我知道columnsX是X視圖。

Answer 1

我們遇到了同樣的問題，Teradata向我們發送了x視圖的替換。

這裏是DBC.ColumnsX腳本：

REPLACE VIEW DBC.ColumnsX 
AS 
SELECT CAST(TRANSLATE(dbase.DatabaseName USING UNICODE_TO_LOCALE 
         WITH ERROR) AS CHAR(30)) (NAMED DatabaseName), 
     CAST(TRANSLATE(tvm.tvmname USING UNICODE_TO_LOCALE WITH ERROR) 
      AS CHAR(30)) (NAMED TableName), 
     CAST(TRANSLATE(tvfields.fieldname USING UNICODE_TO_LOCALE WITH ERROR) 
      AS CHAR(30)) (NAMED ColumnName), 
     CAST(tvfields.fieldformat AS CHAR(30)) (NAMED ColumnFormat), 
     CAST(tvfields.fieldtitle AS VARCHAR(60)) (NAMED ColumnTitle), 
     tvfields.SPParameterType(NAMED SPParameterType), 
     tvfields.fieldtype(NAMED ColumnType), 
     CAST(TRANSLATE(tvfields.UDTName USING UNICODE_TO_LOCALE WITH ERROR) 
      AS CHAR(30))(NAMED ColumnUDTName), 
     tvfields.maxlength(NAMED ColumnLength,FORMAT 'Z,ZZZ,ZZZ,ZZ9'), 
     tvfields.DefaultValue, 
     tvfields.Nullable, 
     tvfields.CommentString, 
     tvfields.TotalDigits(NAMED DecimalTotalDigits,FORMAT 'Z9'), 
     tvfields.ImpliedPoint(NAMED DecimalFractionalDigits,FORMAT 'Z9'), 
     tvfields.FieldId(NAMED ColumnId), 
     tvfields.UpperCaseFlag, 
     tvfields.Compressible, 
     NULL(NAMED CompressValue), 
     TRANSLATE(tvfields.ColumnCheck USING UNICODE_TO_LOCALE WITH ERROR) 
     (NAMED ColumnConstraint), 
     tvfields.CheckCount (NAMED ConstraintCount), 
     CAST(TRANSLATE(DB1.DatabaseName USING UNICODE_TO_LOCALE WITH ERROR) 
      AS CHAR(30)) (named CreatorName), 
     tvfields.CreateTimeStamp, 
     CAST(TRANSLATE(DB2.DatabaseName USING UNICODE_TO_LOCALE WITH ERROR) 
      AS CHAR(30)) (named LastAlterName), 
     tvfields.LastAlterTimeStamp, 
     tvfields.CharType, 
     tvfields.IdColType, 
     tvfields.AccessCount, 
     tvfields.LastAccessTimeStamp, 
     tvfields.CompressValueList, 
     tvfields.TimeDimension, 
     tvfields.VTCheckType, 
     tvfields.TTCheckType 
FROM DBC.tvfields 
     LEFT OUTER JOIN DBC.Dbase DB1 
         ON DBC.tvfields.CreateUID = DB1.DatabaseID 
     LEFT OUTER JOIN DBC.Dbase DB2 
         ON DBC.tvfields.LastAlterUID = DB2.DatabaseID, 
    DBC.dbase, DBC.TVM 
WHERE tvm.DatabaseId = dbase.DatabaseId 
AND tvm.tvmid = tvfields.tableid 
AND (tvm.tvmid IN 
     (/* IDs of tables accessible to the USER */ 
     SELECT tvm.tvmid 
     FROM TVM, DBASE, ACCESSRIGHTS 
     WHERE tvm.tvmid <> '000000000000'xb 
     AND  dbase.DataBaseNameI = USER 
     AND  (
        /* User has right on all in TVMs DB */ 
        (tvm.DatabaseId = accessrights.DatabaseId AND 
        accessrights.tvmid = '000000000000'xb AND 
        accessrights.UserId = dbase.DatabaseId) 
       OR 
        /* TVMs DB has right granted to *PUBLIC* */ 
        (tvm.DatabaseId = accessrights.DatabaseId AND 
        accessrights.tvmid = '000000000000'xb AND 
        accessrights.Userid = '00000300'xb) 
       ) 
     union 
     SELECT tvm.tvmid 
     FROM TVM, DBASE, ACCESSRIGHTS 
     WHERE tvm.tvmid <> '000000000000'xb 
     AND  dbase.DataBaseNameI = USER 
     AND  (
        /* User has right on this specific TVM */ 
        (tvm.tvmid = accessrights.tvmid AND 
        accessrights.UserId=dbase.DatabaseId) 
       OR 
        /* Specific TVM has right granted to *PUBLIC* */ 
        (tvm.tvmid = accessrights.tvmid AND 
        accessrights.UserId= '00000300'xb) 
       ) 
     union 
     SELECT tvm.tvmid 
     FROM TVM, DBASE, OWNERS 
     WHERE tvm.tvmid <> '000000000000'xb 
     AND  dbase.DataBaseNameI = USER 
     AND 
        /* User owns TVMs DB */ 
        (tvm.DatabaseId = owners.owneeid AND 
        owners.ownerid = dbase.DatabaseId) 
     union 
     SELECT tvm.tvmid 
     FROM TVM , DBASE 
     WHERE tvm.tvmid <> '000000000000'xb 
     AND  dbase.DataBaseNameI = USER 
     AND 
        /* User *IS* TVMs DB */ 
        (tvm.DatabaseId = dbase.DatabaseId) 
     ) 
     OR tvm.tvmid IN 
     (/* IDs of tables accessible to USER's roles */ 
     SELECT tvm.tvmid 
     FROM TVM, ACCESSRIGHTS, ROLES 
     WHERE TVM.tvmid  <> '000000000000'xb 
     AND Roles.RoleId = AccessRights.UserId 
     AND ROLE IS NOT NULL 
     AND AccessRights.UserId IN 
       (SELECT RoleAccr.RoleId 
       FROM DBC.Roles RoleAccr) 
     AND (
       /* Role has right on all in TVMs DB */ 
       (tvm.DatabaseId  = accessrights.DatabaseId AND 
        accessrights.tvmid = '000000000000'xb) 
       ) 
     AND (
       (UPPER(ROLE) <> 'ALL' AND 
        /* Restrict to rights granted to current role */ 
        /* and the roles nested within current role */ 
        (Roles.RoleId = 
        (SELECT CurRole.RoleId 
        FROM DBC.Roles CurRole 
        WHERE CurRole.RoleNameI = ROLE) 
        OR 
        Roles.RoleId IN 
        (SELECT RG.RoleId 
         FROM DBC.RoleGrants RG, 
          DBC.Roles  CurRole 
         WHERE RG.GranteeId = CurRole.RoleId AND 
          CurRole.RoleNameI = ROLE)) 
       ) 
       OR 
       (UPPER(ROLE) = 'ALL' AND 
        /* The current role is ALL. Restrict to rights from */ 
        /* the roles directly granted to current user and */ 
        /* nested roles within them */ 
        (Roles.RoleId IN 
        (SELECT UsrRG.RoleId 
        FROM DBC.RoleGrants UsrRG, 
          DBC.Dbase  UserDB 
        WHERE UsrRG.GranteeId = UserDB.DatabaseId AND 
          UserDB.DatabaseNameI = USER) 
        OR 
        Roles.RoleId IN 
        (SELECT RG.RoleId 
        FROM DBC.RoleGrants RG 
        WHERE RG.GranteeId in 
          (SELECT UsrRG.RoleId 
          FROM DBC.RoleGrants UsrRG, 
            DBC.Dbase  UserDB 
          WHERE UsrRG.GranteeId = UserDB.DatabaseId AND 
            UserDB.DatabaseNameI = USER))) 
       ) 
       ) 
     UNION ALL 
     SELECT tvm.tvmid 
     FROM TVM, ACCESSRIGHTS, ROLES 
     WHERE TVM.tvmid  <> '000000000000'xb 
     AND Roles.RoleId = AccessRights.UserId 
     AND ROLE IS NOT NULL 
     AND AccessRights.UserId IN 
       (SELECT RoleAccr.RoleId 
       FROM DBC.Roles RoleAccr) 
     AND (
       /* Role has right on this specific TVM */ 
       (tvm.tvmid   = accessrights.tvmid) 
       ) 
     AND (
       (UPPER(ROLE) <> 'ALL' AND 
        /* Restrict to rights granted to current role */ 
        /* and the roles nested within current role */ 
        (Roles.RoleId = 
        (SELECT CurRole.RoleId 
        FROM DBC.Roles CurRole 
        WHERE CurRole.RoleNameI = ROLE) 
        OR 
        Roles.RoleId IN 
        (SELECT RG.RoleId 
         FROM DBC.RoleGrants RG, 
          DBC.Roles  CurRole 
         WHERE RG.GranteeId = CurRole.RoleId AND 
          CurRole.RoleNameI = ROLE)) 
       ) 
       OR 
       (UPPER(ROLE) = 'ALL' AND 
        /* The current role is ALL. Restrict to rights from */ 
        /* the roles directly granted to current user and */ 
        /* nested roles within them */ 
        (Roles.RoleId IN 
        (SELECT UsrRG.RoleId 
        FROM DBC.RoleGrants UsrRG, 
          DBC.Dbase  UserDB 
        WHERE UsrRG.GranteeId = UserDB.DatabaseId AND 
          UserDB.DatabaseNameI = USER) 
        OR 
        Roles.RoleId IN 
        (SELECT RG.RoleId 
        FROM DBC.RoleGrants RG 
        WHERE RG.GranteeId in 
          (SELECT UsrRG.RoleId 
          FROM DBC.RoleGrants UsrRG, 
            DBC.Dbase  UserDB 
          WHERE UsrRG.GranteeId = UserDB.DatabaseId AND 
            UserDB.DatabaseNameI = USER))) 
       ) 
       ) 
     ) 
    ) WITH CHECK OPTION;