opensql/ShortPeriodIOLatencies.sql at master · lestatkim/opensql · GitHub

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--Summary:  Short snapshot of I/O latencies (uses WAITFOR DELAY '00:10:00';)

IF EXISTS (SELECT * FROM [tempdb].[sys].[objects]
    WHERE [name] = N'##IOStats1')
    DROP TABLE [##IOStats1];

IF EXISTS (SELECT * FROM [tempdb].[sys].[objects]
    WHERE [name] = N'##IOStats2')
    DROP TABLE [##IOStats2];
GO

SELECT [database_id], [file_id], [num_of_reads], [io_stall_read_ms],
       [num_of_writes], [io_stall_write_ms], [io_stall],
       [num_of_bytes_read], [num_of_bytes_written], [file_handle]
INTO ##IOStats1
FROM sys.dm_io_virtual_file_stats (NULL, NULL);
GO

WAITFOR DELAY '00:10:00';
GO

SELECT [database_id], [file_id], [num_of_reads], [io_stall_read_ms],
       [num_of_writes], [io_stall_write_ms], [io_stall],
       [num_of_bytes_read], [num_of_bytes_written], [file_handle]
INTO ##IOStats2
FROM sys.dm_io_virtual_file_stats (NULL, NULL);
GO

WITH [DiffLatencies] AS
(SELECT
-- Files that weren't in the first snapshot
        [ts2].[database_id],
        [ts2].[file_id],
        [ts2].[num_of_reads],
        [ts2].[io_stall_read_ms],
        [ts2].[num_of_writes],
        [ts2].[io_stall_write_ms],
        [ts2].[io_stall],
        [ts2].[num_of_bytes_read],
        [ts2].[num_of_bytes_written]
    FROM [##IOStats2] AS [ts2]
    LEFT OUTER JOIN [##IOStats1] AS [ts1]
        ON [ts2].[file_handle] = [ts1].[file_handle]
    WHERE [ts1].[file_handle] IS NULL
UNION
SELECT
-- Diff of latencies in both snapshots
        [ts2].[database_id],
        [ts2].[file_id],
        [ts2].[num_of_reads] - [ts1].[num_of_reads] AS [num_of_reads],
        [ts2].[io_stall_read_ms] - [ts1].[io_stall_read_ms] AS [io_stall_read_ms],
        [ts2].[num_of_writes] - [ts1].[num_of_writes] AS [num_of_writes],
        [ts2].[io_stall_write_ms] - [ts1].[io_stall_write_ms] AS [io_stall_write_ms],
        [ts2].[io_stall] - [ts1].[io_stall] AS [io_stall],
        [ts2].[num_of_bytes_read] - [ts1].[num_of_bytes_read] AS [num_of_bytes_read],
        [ts2].[num_of_bytes_written] - [ts1].[num_of_bytes_written] AS [num_of_bytes_written]
    FROM [##IOStats2] AS [ts2]
    LEFT OUTER JOIN [##IOStats1] AS [ts1]
        ON [ts2].[file_handle] = [ts1].[file_handle]
    WHERE [ts1].[file_handle] IS NOT NULL)
SELECT
    DB_NAME ([vfs].[database_id]) AS [DB],
    LEFT ([mf].[physical_name], 2) AS [Drive],
    [mf].[type_desc],
    [num_of_reads] AS [Reads],
    [num_of_writes] AS [Writes],
    [ReadLatency(ms)] =
        CASE WHEN [num_of_reads] = 0
            THEN 0 ELSE ([io_stall_read_ms] / [num_of_reads]) END,
    [WriteLatency(ms)] =
        CASE WHEN [num_of_writes] = 0
            THEN 0 ELSE ([io_stall_write_ms] / [num_of_writes]) END,
    /*[Latency] =
        CASE WHEN ([num_of_reads] = 0 AND [num_of_writes] = 0)
            THEN 0 ELSE ([io_stall] / ([num_of_reads] + [num_of_writes])) END,*/
    [AvgBPerRead] =
        CASE WHEN [num_of_reads] = 0
            THEN 0 ELSE ([num_of_bytes_read] / [num_of_reads]) END,
    [AvgBPerWrite] =
        CASE WHEN [num_of_writes] = 0
            THEN 0 ELSE ([num_of_bytes_written] / [num_of_writes]) END,
    /*[AvgBPerTransfer] =
        CASE WHEN ([num_of_reads] = 0 AND [num_of_writes] = 0)
            THEN 0 ELSE
                (([num_of_bytes_read] + [num_of_bytes_written]) /
                ([num_of_reads] + [num_of_writes])) END,*/
    [mf].[physical_name]
FROM [DiffLatencies] AS [vfs]
JOIN sys.master_files AS [mf]
    ON [vfs].[database_id] = [mf].[database_id]
    AND [vfs].[file_id] = [mf].[file_id]
-- ORDER BY [ReadLatency(ms)] DESC
ORDER BY [WriteLatency(ms)] DESC;
GO

-- Cleanup
IF EXISTS (SELECT * FROM [tempdb].[sys].[objects]
    WHERE [name] = N'##IOStats1')
    DROP TABLE [##IOStats1];

IF EXISTS (SELECT * FROM [tempdb].[sys].[objects]
    WHERE [name] = N'##IOStats2')
    DROP TABLE [##IOStats2];
GO