SQL Server Sp_msforeachdb query character without limitation

Rédigé par M Sozezzo - - Aucun commentaire

When we write a query than is running for every database in the instance of SQL Server, we use Sp_msforeachdb.
 
If your query is bigger than 2000 chars, the query cannot work because Sp_msforeachdb has a character limitation of 2000 chars.

The solution is to re-create MySp_myforeachdb. We use sp_helptext to see the definition of sp_MSforeachdb and sp_MSforeach_worker, and we change to a new character limitation of 262144 chars.


Everything works as before but without character limitation of 2000 chars.


sp_Myforeachdb



USE master;
GO
/*
 * This is the worker proc for all of the "for each" type procs.  Its function is to read the
 * next replacement name from the cursor (which returns only a single name), plug it into the
 * replacement locations for the commands, and execute them.  It assumes the cursor "hCForEach***"
 * has already been opened by its caller.
 * worker_type is a parameter that indicates whether we call this for a database (1) or for a table (0)
 */
create proc dbo.sp_Myforeach_worker
 @command1 nvarchar(max), @replacechar nchar(1) = N'?', @command2 nvarchar(max) = null, @command3 nvarchar(max) = null, @worker_type int =1
as

 create table #qtemp ( /* Temp command storage */
  qnum    int    NOT NULL,
  qchar    nvarchar(max) COLLATE database_default NULL
 )

 set nocount on
 declare @name nvarchar(517), @namelen int, @q1 nvarchar(max), @q2 nvarchar(max)
   declare @q3 nvarchar(max), @q4 nvarchar(max), @q5 nvarchar(max)
 declare @q6 nvarchar(max), @q7 nvarchar(max), @q8 nvarchar(max), @q9 nvarchar(max), @q10 nvarchar(max)
 declare @cmd nvarchar(max), @replacecharindex int, @useq tinyint, @usecmd tinyint, @nextcmd nvarchar(max)
   declare @namesave nvarchar(517), @nametmp nvarchar(517), @nametmp2 nvarchar(258)

 declare @local_cursor cursor
 if @worker_type=1 
  set @local_cursor = hCForEachDatabase
 else
  set @local_cursor = hCForEachTable
 
 open @local_cursor
 fetch @local_cursor into @name

 /* Loop for each database */
 while (@@fetch_status >= 0) begin
  /* Initialize. */

      /* save the original dbname */
      select @namesave = @name
  select @useq = 1, @usecmd = 1, @cmd = @command1, @namelen = datalength(@name)
  while (@cmd is not null) begin  /* Generate @q* for exec() */
   /*
    * Parse each @commandX into a single executable batch.
    * Because the expanded form of a @commandX may be > OSQL_MAXCOLLEN_SET, we'll need to allow overflow.
    * We also may append @commandX's (signified by '++' as first letters of next @command).
    */
   select @replacecharindex = charindex(@replacechar, @cmd)
   while (@replacecharindex <> 0) begin

            /* 7.0, if name contains ' character, and the name has been single quoted in command, double all of them in dbname */
            /* if the name has not been single quoted in command, do not doulbe them */
            /* if name contains ] character, and the name has been [] quoted in command, double all of ] in dbname */
            select @name = @namesave
            select @namelen = datalength(@name)
            declare @tempindex int
            if (substring(@cmd, @replacecharindex - 1, 1) = N'''') begin
               /* if ? is inside of '', we need to double all the ' in name */
               select @name = REPLACE(@name, N'''', N'''''')
            end else if (substring(@cmd, @replacecharindex - 1, 1) = N'[') begin
               /* if ? is inside of [], we need to double all the ] in name */
               select @name = REPLACE(@name, N']', N']]')
            end else if ((@name LIKE N'%].%]') and (substring(@name, 1, 1) = N'[')) begin
               /* ? is NOT inside of [] nor '', and the name is in [owner].[name] format, handle it */
               /* !!! work around, when using LIKE to find string pattern, can't use '[', since LIKE operator is treating '[' as a wide char */
               select @tempindex = charindex(N'].[', @name)
               select @nametmp  = substring(@name, 2, @tempindex-2 )
               select @nametmp2 = substring(@name, @tempindex+3, len(@name)-@tempindex-3 )
               select @nametmp  = REPLACE(@nametmp, N']', N']]')
               select @nametmp2 = REPLACE(@nametmp2, N']', N']]')
               select @name = N'[' + @nametmp + N'].[' + @nametmp2 + ']'
            end else if ((@name LIKE N'%]') and (substring(@name, 1, 1) = N'[')) begin
               /* ? is NOT inside of [] nor '', and the name is in [name] format, handle it */
       /* j.i.c., since we should not fall into this case */
               /* !!! work around, when using LIKE to find string pattern, can't use '[', since LIKE operator is treating '[' as a wide char */
               select @nametmp = substring(@name, 2, len(@name)-2 )
               select @nametmp = REPLACE(@nametmp, N']', N']]')
               select @name = N'[' + @nametmp + N']'
            end
            /* Get the new length */
            select @namelen = datalength(@name)

            /* start normal process */
    if (datalength(@cmd) + @namelen - 1 > 262144) begin
     /* Overflow; put preceding stuff into the temp table */
     if (@useq > 9) begin
      close @local_cursor
      if @worker_type=1 
       deallocate hCForEachDatabase
      else
       deallocate hCForEachTable
       
      RAISERROR(55555, 16, 1); -- N'sp_MSforeach_worker assert failed:  command too long'
      return 1
     end
     if (@replacecharindex < @namelen) begin
      /* If this happened close to beginning, make sure expansion has enough room. */
      /* In this case no trailing space can occur as the row ends with @name. */
      select @nextcmd = substring(@cmd, 1, @replacecharindex)
      select @cmd = substring(@cmd, @replacecharindex + 1, 262144)
      select @nextcmd = stuff(@nextcmd, @replacecharindex, 1, @name)
      select @replacecharindex = charindex(@replacechar, @cmd)
      insert #qtemp values (@useq, @nextcmd)
      select @useq = @useq + 1
      continue
     end
     /* Move the string down and stuff() in-place. */
     /* Because varchar columns trim trailing spaces, we may need to prepend one to the following string. */
     /* In this case, the char to be replaced is moved over by one. */
     insert #qtemp values (@useq, substring(@cmd, 1, @replacecharindex - 1))
     if (substring(@cmd, @replacecharindex - 1, 1) = N' ') begin
      select @cmd = N' ' + substring(@cmd, @replacecharindex, 262144)
      select @replacecharindex = 2
     end else begin
      select @cmd = substring(@cmd, @replacecharindex, 262144)
      select @replacecharindex = 1
     end
     select @useq = @useq + 1
    end
    select @cmd = stuff(@cmd, @replacecharindex, 1, @name)
    select @replacecharindex = charindex(@replacechar, @cmd)
   end

   /* Done replacing for current @cmd.  Get the next one and see if it's to be appended. */
   select @usecmd = @usecmd + 1
   select @nextcmd = case (@usecmd) when 2 then @command2 when 3 then @command3 else null end
   if (@nextcmd is not null and substring(@nextcmd, 1, 2) = N'++') begin
    insert #qtemp values (@useq, @cmd)
    select @cmd = substring(@nextcmd, 3, 262144), @useq = @useq + 1
    continue
   end

   /* Now exec() the generated @q*, and see if we had more commands to exec().  Continue even if errors. */
   /* Null them first as the no-result-set case won't. */
   select @q1 = null, @q2 = null, @q3 = null, @q4 = null, @q5 = null, @q6 = null, @q7 = null, @q8 = null, @q9 = null, @q10 = null
   select @q1 = qchar from #qtemp where qnum = 1
   select @q2 = qchar from #qtemp where qnum = 2
   select @q3 = qchar from #qtemp where qnum = 3
   select @q4 = qchar from #qtemp where qnum = 4
   select @q5 = qchar from #qtemp where qnum = 5
   select @q6 = qchar from #qtemp where qnum = 6
   select @q7 = qchar from #qtemp where qnum = 7
   select @q8 = qchar from #qtemp where qnum = 8
   select @q9 = qchar from #qtemp where qnum = 9
   select @q10 = qchar from #qtemp where qnum = 10
   truncate table #qtemp
   exec (@q1 + @q2 + @q3 + @q4 + @q5 + @q6 + @q7 + @q8 + @q9 + @q10 + @cmd)
   select @cmd = @nextcmd, @useq = 1
  end /* while @cmd is not null, generating @q* for exec() */

  /* All commands done for this name.  Go to next one. */
  fetch @local_cursor into @name
 end /* while FETCH_SUCCESS */
 close @local_cursor
 if @worker_type=1 
  deallocate hCForEachDatabase
 else
  deallocate hCForEachTable
  
 return 0

GO

GO
CREATE PROC sp_Myforeachdb
 @command1 nvarchar(max), @replacechar nchar(1) = N'?', @command2 nvarchar(max) = null, @command3 nvarchar(max) = null, 
 @precommand nvarchar(max) = null, @postcommand nvarchar(max) = null
 AS

 set deadlock_priority low 
     
 /* This proc returns one or more rows for each accessible db, with each db defaulting to its own result set */ 
 /* @precommand and @postcommand may be used to force a single result set via a temp table. */ 
 
 /* Preprocessor won't replace within quotes so have to use str(). */ 
 declare @inaccessible nvarchar(12), @invalidlogin nvarchar(12), @dbinaccessible nvarchar(12) 
 select @inaccessible = ltrim(str(convert(int, 0x03e0), 11)) 
 select @invalidlogin = ltrim(str(convert(int, 0x40000000), 11)) 
 select @dbinaccessible = N'0x80000000'  /* SQLDMODbUserProf_InaccessibleDb; the negative number doesn't work in convert() */ 
 
 if (@precommand is not null) 
  exec(@precommand) 
 
 declare @origdb nvarchar(128) 
 select @origdb = db_name() 
 
 /* If it's a single user db and there's an entry for it in sysprocesses who isn't us, we can't use it. */ 
   /* Create the select */ 
 exec(N'declare hCForEachDatabase cursor global for select name from master.dbo.sysdatabases d ' + 
   N' where (d.status & ' + @inaccessible + N' = 0)' + 
   N' and (DATABASEPROPERTYEX(d.name, ''UserAccess'') <> ''SINGLE_USER'' and (has_dbaccess(d.name) = 1))' ) 
 
 declare @retval int 
 select @retval = @@error 
 if (@retval = 0) 
  exec @retval = dbo.sp_Myforeach_worker @command1, @replacechar, @command2, @command3, 1 
 
 if (@retval = 0 and @postcommand is not null) 
  exec(@postcommand) 
 
   declare @tempdb nvarchar(258) 
   SELECT @tempdb = REPLACE(@origdb, N']', N']]') 
   exec (N'use ' + N'[' + @tempdb + N']') 
 
 return @retval 
GO  

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