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sys.allocation_unitsおよびsp_spaceusedのスペース使用

DMVがページ数と行数に関する正確な情報を保持しないことは既知の事実です。ただし、統計を更新しても、なぜ更新されないのかわかりません。

監視ツールに取り組んでいます。各インデックスとデータのディスクサイズなどを知りたいと思っています。最終的には、適切なFILL FACTORなどを見つけたいと思っています。

私の関数と古いsp_spaceusedで使用されるスペースは、スペースの使用状況では少し異なりますが、レコード数では異なります。

私の選択に欠けているものがあるかどうかわかりますか?

これはsp_spaceusedです(その後、MBで数値を変換します)。

sp_spaceused 'tblBOrderRelationship'
go

select 318008/1024.00 AS reserved,
140208/1024.00  AS data,
177048/1024.00 AS index_size,
752/1024.00    AS unused

enter image description here

しかし、selectを実行すると、以下のコードの下の画像を実行すると、少し異なる数値が表示されます。

SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED

SELECT 
    schema_name(t.schema_id) as SchemaName,
    t.NAME AS TableName,
    t.type_desc,
    t.is_ms_shipped,
    t.is_published,
    t.lob_data_space_id,
    t.filestream_data_space_id,
    t.is_replicated,
    t.has_replication_filter,
    t.is_merge_published,
    t.is_sync_tran_subscribed,
    --t.is_filetable,
    i.name as indexName,
    i.type_desc,
    i.is_unique,
    i.is_primary_key,
    i.is_unique_constraint,
    i.fill_factor,
    i.is_padded,


    sum(p.rows)               OVER (PARTITION BY t.OBJECT_ID,i.index_id)  as RowCounts,
    sum(a.total_pages)        OVER (PARTITION BY t.OBJECT_ID,i.index_id)  as TotalPages, 
    sum(a.used_pages)         OVER (PARTITION BY t.OBJECT_ID,i.index_id)  as UsedPages, 
    sum(a.data_pages)         OVER (PARTITION BY t.OBJECT_ID,i.index_id)  as DataPages,

    (sum(a.total_pages)       OVER (PARTITION BY t.OBJECT_ID,i.index_id)  * 8) / 1024 as TotalSpaceMB, 
    (sum(a.used_pages)        OVER (PARTITION BY t.OBJECT_ID,i.index_id)  * 8) / 1024 as UsedSpaceMB, 
    (sum(a.data_pages)        OVER (PARTITION BY t.OBJECT_ID,i.index_id)  * 8) / 1024 as DataSpaceMB
FROM 
    sys.tables t
INNER JOIN      
    sys.indexes i ON t.OBJECT_ID = i.object_id
INNER JOIN 
    sys.partitions p ON i.object_id = p.OBJECT_ID AND i.index_id = p.index_id
INNER JOIN 
    sys.allocation_units a ON p.partition_id = a.container_id
WHERE 
    t.NAME NOT LIKE 'dt%' AND
    i.OBJECT_ID > 255 
AND T.NAME = 'tblBOrderRelationship'

統計

the figures

インデックス名を含む全体像 the bigger picture, including the index names

結果を確認するためにいくつかの計算を行っています:

--==================================
-- the figures from sp_spaceused
--==================================
select 318008/1024.00 AS reserved,
140208/1024.00  AS data,
177048/1024.00 AS index_size,
752/1024.00    AS unused

--==================================
-- the figures from my select
--==================================
select 137+61+56+54 AS reserved,
       137 AS data,
       61+56+54 AS index_size

enter image description here

私が未使用のスペースを計算しなかったという事実を除けば、それほど遠くはありません。

これを正確にするにはどうすればよいですか?

変更後:

1024を1024.00に置き換えた後、結果ははるかに正確になります。問題のテーブルにレコードが挿入されていることに気づきました。明らかに統計は最新ではありませんが、それでも結果は一致しています(1 MB未満の差-これで十分です)。

新しい結果セットは次のとおりです。

--==================================
-- the figures from sp_spaceused
--==================================
select
318072 /1024.00 AS reserved,
140208 /1024.00 AS data,
177096 /1024.00 AS index_size,
768 /1024.00 AS unused
go

--==================================
-- the figures from my select
--==================================
select 137.7578125+61.7968750+56.4218750+54.6406250 as reserved,
       137.7578125 as data,
       61.7968750+56.4218750+54.6406250 as index_size

enter image description here

13

即時の丸めの問題を修正しても、オブジェクトごと/インデックスの統計を取得するための全体的なアルゴリズムは正しくありません。 LOBおよび行オーバーフローデータを適切に処理しません。また、インデックス付きビュー、フルテキストインデックス、XMLインデックス、およびその他のいくつかのケースも除外されます。したがって、すべてのデータが表示されない場合があります。

以下は、sp_spaceusedが処理するすべてのケースを処理するStackOverflow( sp_spaceused-SQLのすべてのテーブルでGBでサイズを測定する方法 )の回答に投稿したコードの適応です。そのS.O.質問はインデックスごとではなくオブジェクトごとの統計にのみ関係していたので、インデックスレベルで処理するようにコードを調整しました。

;WITH agg AS
(   -- Get info for Tables, Indexed Views, etc
    SELECT  ps.[object_id] AS [ObjectID],
            ps.index_id AS [IndexID],
            NULL AS [ParentIndexID],
            NULL AS [PassThroughIndexName],
            NULL AS [PassThroughIndexType],
            SUM(ps.in_row_data_page_count) AS [InRowDataPageCount],
            SUM(ps.used_page_count) AS [UsedPageCount],
            SUM(ps.reserved_page_count) AS [ReservedPageCount],
            SUM(ps.row_count) AS [RowCount],
            SUM(ps.lob_used_page_count + ps.row_overflow_used_page_count)
                    AS [LobAndRowOverflowUsedPageCount]
    FROM    sys.dm_db_partition_stats ps
    GROUP BY    ps.[object_id],
                ps.[index_id]
    UNION ALL
    -- Get info for FullText indexes, XML indexes, Spatial indexes, etc
    SELECT  sit.[parent_id] AS [ObjectID],
            sit.[object_id] AS [IndexID],
            sit.[parent_minor_id] AS [ParentIndexID],
            sit.[name] AS [PassThroughIndexName],
            sit.[internal_type_desc] AS [PassThroughIndexType],
            0 AS [InRowDataPageCount],
            SUM(ps.used_page_count) AS [UsedPageCount],
            SUM(ps.reserved_page_count) AS [ReservedPageCount],
            0 AS [RowCount],
            0 AS [LobAndRowOverflowUsedPageCount]
    FROM    sys.dm_db_partition_stats ps
    INNER JOIN  sys.internal_tables sit
            ON  sit.[object_id] = ps.[object_id]
    WHERE   sit.internal_type IN
               (202, 204, 207, 211, 212, 213, 214, 215, 216, 221, 222, 236)
    GROUP BY    sit.[parent_id],
                sit.[object_id],
                sit.[parent_minor_id],
                sit.[name],
                sit.[internal_type_desc]
), spaceused AS
(
SELECT  agg.[ObjectID],
        agg.[IndexID],
        agg.[ParentIndexID],
        agg.[PassThroughIndexName],
        agg.[PassThroughIndexType],
        OBJECT_SCHEMA_NAME(agg.[ObjectID]) AS [SchemaName],
        OBJECT_NAME(agg.[ObjectID]) AS [TableName],
        SUM(CASE
                WHEN (agg.IndexID < 2) THEN agg.[RowCount]
                ELSE 0
            END) AS [Rows],
        SUM(agg.ReservedPageCount) * 8 AS [ReservedKB],
        SUM(agg.LobAndRowOverflowUsedPageCount +
            CASE
                WHEN (agg.IndexID < 2) THEN (agg.InRowDataPageCount)
                ELSE 0
            END) * 8 AS [DataKB],
        SUM(agg.UsedPageCount - agg.LobAndRowOverflowUsedPageCount -
            CASE
                WHEN (agg.IndexID < 2) THEN agg.InRowDataPageCount
                ELSE 0
            END) * 8 AS [IndexKB],
        SUM(agg.ReservedPageCount - agg.UsedPageCount) * 8 AS [UnusedKB],
        SUM(agg.UsedPageCount) * 8 AS [UsedKB]
FROM    agg
GROUP BY    agg.[ObjectID],
            agg.[IndexID],
            agg.[ParentIndexID],
            agg.[PassThroughIndexName],
            agg.[PassThroughIndexType],
            OBJECT_SCHEMA_NAME(agg.[ObjectID]),
            OBJECT_NAME(agg.[ObjectID])
)
SELECT sp.SchemaName,
       sp.TableName,
       sp.IndexID,
       CASE
         WHEN (sp.IndexID > 0) THEN COALESCE(si.[name], sp.[PassThroughIndexName])
         ELSE N'<Heap>'
       END AS [IndexName],
       sp.[PassThroughIndexName] AS [InternalTableName],
       sp.[Rows],
       sp.ReservedKB,
       (sp.ReservedKB / 1024.0 / 1024.0) AS [ReservedGB],
       sp.DataKB,
       (sp.DataKB / 1024.0 / 1024.0) AS [DataGB],
       sp.IndexKB,
       (sp.IndexKB / 1024.0 / 1024.0) AS [IndexGB],
       sp.UsedKB AS [UsedKB],
       (sp.UsedKB / 1024.0 / 1024.0) AS [UsedGB],
       sp.UnusedKB,
       (sp.UnusedKB / 1024.0 / 1024.0) AS [UnusedGB],
       so.[type_desc] AS [ObjectType],
       COALESCE(si.type_desc, sp.[PassThroughIndexType]) AS [IndexPrimaryType],
       sp.[PassThroughIndexType] AS [IndexSecondaryType],
       SCHEMA_ID(sp.[SchemaName]) AS [SchemaID],
       sp.ObjectID
       --,sp.ParentIndexID
FROM   spaceused sp
INNER JOIN sys.all_objects so -- in case "WHERE so.is_ms_shipped = 0" is removed
        ON so.[object_id] = sp.ObjectID
LEFT JOIN  sys.indexes si
       ON  si.[object_id] = sp.ObjectID
      AND  (si.[index_id] = sp.IndexID
         OR si.[index_id] = sp.[ParentIndexID])
WHERE so.is_ms_shipped = 0
--so.[name] LIKE N''  -- optional name filter
--ORDER BY ????
24
Solomon Rutzky

INTで除算しているため、整数の答えしか得られません。

したがって、独自のスペース計算で丸め問題が発生します。これが、それらを合計すると、異なる答えが得られる理由です。

違いはごくわずかですが、これはSQL Serverで整数以外の数値を処理する際の重要な問題の1つです。

手順でパーティションクエリを変更します。

(sum(a.total_pages)       OVER (PARTITION BY t.OBJECT_ID,i.index_id)  * 8) / 1024.00 as TotalSpaceMB, 
(sum(a.used_pages)        OVER (PARTITION BY t.OBJECT_ID,i.index_id)  * 8) / 1024.00 as UsedSpaceMB, 
(sum(a.data_pages)        OVER (PARTITION BY t.OBJECT_ID,i.index_id)  * 8) / 1024.00 as DataSpaceMB
8
Mark Sinkinson