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patternsqlMinor

Update statistics on sys.objects

Submitted by: @import:stackexchange-dba··
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sysstatisticsupdateobjects

Problem

I am working on a query to give me all the database objects that depend directly or indirectly in any level, to a table called dbo.tblborder, which is heavily depended on.

However, this question in particular is related to the query plan of this query,
because I see warnings in the query plan (in the distinct sort operators)
two types of warnings, one related to spillage to tempDB and the other warning related to conversion of data types and cardinality estimate.

the query and the query plan are further down, after the pictures.
Questions

As I am dealing with system objects, how can I find out which ones I need to update the statistics?

Or otherwise, how to get out of this warning on the query plan?

And regarding the data type conversion, is there anything I can do to avoid this, and the cardinality estimate issue?

Some trace flag maybe?

it is a database of 600GB, I would like to find all the dependencies on a specific table, first level alone shows me 325 objects, but it is not a query I would run everyday. I am interested in clearing those warnings, but it is not a question of life and death.
Information

1st picture of warning on spillage on tempdb:

2nd picture of warning on spillage on tempdb:

3rd warning - related to data type conversion and may affect cardinality estimation:

```
;WITH Radhe AS (

SELECT DISTINCT
s2.object_id,
Name=SCHEMA_NAME(S2.schema_id) + '.' + S2.Name,
ObjectType = S2.Type,
DependsOn = s1.object_id,
DependsOn_Name=SCHEMA_NAME(S1.schema_id) + '.' + S1.Name,
0 as Level

FROM sys.sysdepends DP

INNER JOIN sys.objects S1
ON S1.object_id = DP.DepID

INNER JOIN sys.objects S2
ON S2.object_id = DP.ID

WHERE S1.object_id = OBJECT_ID('DBO.tblborder')

UNION ALL

SELECT
s2.object_id,
Name=SCHEMA_NAME(S2.schema_i

Solution

The warnings you're seeing most likely come from the sys.sysdepends view.

If you script it out using

EXEC sys.sp_helptext @objname = N'sys.sysdepends'


The definition has a bunch of converts and other nonsense going on.

CREATE VIEW sys.sysdepends AS  
 SELECT  
  id = object_id,  
  depid = referenced_major_id,  
  number = convert(smallint,  
   case when objectproperty(object_id, 'isprocedure') = 1 then 1 else column_id end),  
  depnumber = convert(smallint, referenced_minor_id),  
  status = convert(smallint, is_select_all * 2 + is_updated * 4 + is_selected * 8),  
  deptype = class,  
  depdbid = convert(smallint, 0),  
  depsiteid = convert(smallint, 0),  
  selall = is_select_all,  
  resultobj = is_updated,  
  readobj = is_selected  
 FROM sys.sql_dependencies  
 WHERE class < 2  
 UNION ALL  
 SELECT  -- blobtype dependencies  
  id = object_id, depid = object_id,  
  number = convert(smallint, column_id), depnumber = convert(smallint, type_column_id),  
  status = convert(smallint, 0), deptype = sysconv(tinyint, 1),  
  depdbid = convert(smallint, 0), depsiteid = convert(smallint, 0),  
  selall = sysconv(bit, 0), resultobj = sysconv(bit, 0), readobj = sysconv(bit, 0)  
 FROM sys.fulltext_index_columns  
 WHERE type_column_id IS NOT NULL


sys.objects, on the other hand, is fairly straightforward.

CREATE VIEW sys.objects AS  
 SELECT name,   
  object_id,  
  principal_id,  
  schema_id,  
  parent_object_id,  
  type,   
  type_desc,   
  create_date,   
  modify_date,  
  is_ms_shipped,  
  is_published,  
  is_schema_published  
 FROM sys.objects$


The view definition for sys.sysdepends causes the same warnings when queried on its own.

SELECT *
FROM  sys.sysdepends


In general, if you want to control datatypes and indexes and have some performance tuning ability when referencing system views or tables, your best bet is to dump them into a temp table first.

Code Snippets

EXEC sys.sp_helptext @objname = N'sys.sysdepends'
CREATE VIEW sys.sysdepends AS  
 SELECT  
  id = object_id,  
  depid = referenced_major_id,  
  number = convert(smallint,  
   case when objectproperty(object_id, 'isprocedure') = 1 then 1 else column_id end),  
  depnumber = convert(smallint, referenced_minor_id),  
  status = convert(smallint, is_select_all * 2 + is_updated * 4 + is_selected * 8),  
  deptype = class,  
  depdbid = convert(smallint, 0),  
  depsiteid = convert(smallint, 0),  
  selall = is_select_all,  
  resultobj = is_updated,  
  readobj = is_selected  
 FROM sys.sql_dependencies  
 WHERE class < 2  
 UNION ALL  
 SELECT  -- blobtype dependencies  
  id = object_id, depid = object_id,  
  number = convert(smallint, column_id), depnumber = convert(smallint, type_column_id),  
  status = convert(smallint, 0), deptype = sysconv(tinyint, 1),  
  depdbid = convert(smallint, 0), depsiteid = convert(smallint, 0),  
  selall = sysconv(bit, 0), resultobj = sysconv(bit, 0), readobj = sysconv(bit, 0)  
 FROM sys.fulltext_index_columns  
 WHERE type_column_id IS NOT NULL
CREATE VIEW sys.objects AS  
 SELECT name,   
  object_id,  
  principal_id,  
  schema_id,  
  parent_object_id,  
  type,   
  type_desc,   
  create_date,   
  modify_date,  
  is_ms_shipped,  
  is_published,  
  is_schema_published  
 FROM sys.objects$
SELECT *
FROM  sys.sysdepends

Context

StackExchange Database Administrators Q#171021, answer score: 5

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