Question

我正在使用SQL Server 2012，并编写了一个存储过程，该存储过程使用sys表计算表统计信息。我知道SSMS中有报告可以为您完成此操作，但是，我需要其他信息。似乎我不得不使用动态SQL来实现这一目标，但它似乎又慢又笨拙。我的存储过程可以工作，但是我很好奇，甚至在没有动态SQL的情况下，还有一种更有效的查询写方法？

DECLARE @my_cursor CURSOR, 
        @sql nvarchar(250), @table_name nvarchar(100),
        @days_loaded int, @row_count int, @row_count_per_day int, 
        @used_mb numeric(36,2), @used_mb_per_day numeric(36,2),
        @first_date_loaded date, @last_date_loaded date, 
        @expected_first_date date, @gaps_exist nvarchar(1)

-- Delete temp table #tables in case the stored procedure is ran twice in the same session
IF OBJECT_ID('tempdb.dbo.#tables', 'U') IS NOT NULL 
    DROP TABLE #tables

-- Select all the tables and stats from the dallas schema into a temp table
SELECT 
    s.name + '.' + t.name AS table_name,
    p.rows AS row_count,
    CAST(ROUND(SUM(a.used_pages) / 128.00, 2) AS NUMERIC(36, 2)) AS used_mb
INTO
    #tables
FROM
    sys.tables AS t
INNER JOIN 
    sys.indexes AS i ON t.object_id = i.object_id
INNER JOIN 
    sys.partitions AS p ON i.object_id = p.object_id AND i.index_id = p.index_id
INNER JOIN 
    sys.allocation_units AS a ON p.partition_id = a.container_id
INNER JOIN 
    sys.schemas AS s ON t.schema_id = s.schema_id
WHERE
    s.name = 'dallas'
GROUP BY 
    t.name, s.name, p.rows

-- Add some additional fields in the temp table to be used for population in loop below
ALTER TABLE #tables ADD days_loaded INT NULL
ALTER TABLE #tables ADD used_mb_per_day numeric(36,2) NULL
ALTER TABLE #tables ADD row_count_per_day INT NULL
ALTER TABLE #tables ADD first_date_loaded DATE NULL
ALTER TABLE #tables ADD expected_first_date DATE NULL
ALTER TABLE #tables ADD gaps_exist nvarchar(1) NULL

-- Loop through each table in dallas schema
BEGIN
    SET @my_cursor = CURSOR FOR SELECT table_name, row_count, used_mb FROM #tables

    OPEN @my_cursor

    FETCH NEXT FROM @my_cursor INTO @table_name, @row_count, @used_mb

    WHILE @@FETCH_STATUS = 0
    BEGIN
        -- Calculate first date that was loaded to see history of how far back table goes
        SET @sql = N'SELECT TOP 1 @first_date_loaded = CONVERT(date,Min(data_load_timestamp)) FROM ' + @table_name
        EXECUTE sp_executesql @sql, N'@first_date_loaded date OUTPUT', @first_date_loaded=@first_date_loaded OUTPUT

        -- Calculate last date that was loaded to offset expected first date if needed (data that is loaded day of instead of day before)
        SET @sql = N'SELECT TOP 1 @last_date_loaded = CONVERT(date,Max(data_load_timestamp)) FROM ' + @table_name
        EXECUTE sp_executesql @sql, N'@last_date_loaded date OUTPUT', @last_date_loaded=@last_date_loaded OUTPUT

        -- Calculate days loaded by retrieving count of distinct dates in table
        SET @sql = N'SELECT @days_loaded=COUNT(*) FROM (SELECT DISTINCT CONVERT(date, data_load_timestamp) AS data_load_date FROM ' + @table_name + ') tt'
        EXECUTE sp_executesql @sql, N'@days_loaded int OUTPUT', @days_loaded=@days_loaded OUTPUT
        IF @days_loaded <> 0
            BEGIN
                SET @row_count_per_day = @row_count / @days_loaded
                SET @used_mb_per_day = @used_mb / @days_loaded
                SET @expected_first_date = DATEADD(d,@days_loaded * -1,GETDATE())
                IF @last_date_loaded = CONVERT(date,GETDATE()) SET @expected_first_date = DATEADD(d,1,@expected_first_date)
                IF @first_date_loaded = @expected_first_date
                    SET @gaps_exist = 'N'
                ELSE
                    SET @gaps_exist = 'Y'
            END

        -- Update temp table with additional fields that were calculated
        SET @sql = N'UPDATE #tables SET days_loaded=' + CONVERT(nvarchar,@days_loaded) + 
                   ', row_count_per_day=' + CONVERT(nvarchar, @row_count_per_day) +
                   ', used_mb_per_day=' + CONVERT(nvarchar,@used_mb_per_day) + ', first_date_loaded=''' +
                   CONVERT(nvarchar,@first_date_loaded) + ''', expected_first_date=''' +
                   CONVERT(nvarchar,@expected_first_date) + ''', gaps_exist=''' + @gaps_exist + ''' WHERE table_name=''' + @table_name + ''''
        EXECUTE sp_executesql @sql
        FETCH NEXT FROM @my_cursor INTO @table_name, @row_count, @used_mb
    END
    CLOSE @my_cursor
    DEALLOCATE @my_cursor
END
-- Final return showing results from temp table sorted by largest utilization first
SELECT * FROM #tables ORDER BY used_mb DESC

用于在sys表上查询的SQL Server动态SQL

0 个答案: