Indeks Offline Dibangun Kembali pada Tabel yang Dipartisi

Saya punya waktu untuk melihat ini, dan karena saya sudah memiliki beberapa skrip demo yang ditulis, cukup mudah untuk memeriksa sisanya. Mari kita lakukan pengaturan, lalu lihat hasilnya. Ini akan membuat tabel dan indeks yang perlu dipartisi.

CREATE PARTITION FUNCTION YourMom ( INT )
    AS RANGE LEFT FOR VALUES ( 1000000, 2000000, 3000000, 4000000, 5000000 );

CREATE PARTITION SCHEME YourDad
    AS PARTITION YourMom
    ALL TO ( [PRIMARY] );

CREATE TABLE dbo.YourAuntDebbie
(
    Id INT,
    StopUsingDeprecatedDataTypes NTEXT
) ON YourDad (Id);


DECLARE @counter INT = 1;
WHILE @counter < 6
    BEGIN

        RAISERROR('Run number: %d', 0, 1, @counter) WITH NOWAIT;

        INSERT dbo.YourAuntDebbie WITH ( TABLOCK ) ( Id, StopUsingDeprecatedDataTypes )
        SELECT TOP 1000000 x.n + CASE WHEN @counter = 1 THEN 0
                                      WHEN @counter = 2 THEN 1000000 
                                      WHEN @counter = 3 THEN 2000000 
                                      WHEN @counter = 4 THEN 3000000 
                                      WHEN @counter = 5 THEN 4000000 
                                      ELSE 0 
                                      END, 
                           REPLICATE(N'A', x.n % 10000)
        FROM   (   SELECT ROW_NUMBER() OVER ( ORDER BY @@ROWCOUNT ) AS n
                   FROM   sys.messages AS m
                   CROSS JOIN sys.messages AS m2 ) AS x;

        SET @counter += 1;

    END;

CREATE CLUSTERED INDEX ix_whatever
    ON dbo.YourAuntDebbie ( Id ) ON YourDad(Id);

Itu memberi saya 5 partisi dengan 1 juta baris, dan satu partisi kosong.

SELECT OBJECT_NAME(p.object_id) AS table_name, p.partition_number, p.rows
FROM   sys.partitions AS p
WHERE  p.object_id = OBJECT_ID('dbo.YourAuntDebbie');

Meja mewah:

+----------------+------------------+---------+
|   table_name   | partition_number |  rows   |
+----------------+------------------+---------+
| YourAuntDebbie |                1 | 1000000 |
| YourAuntDebbie |                2 | 1000000 |
| YourAuntDebbie |                3 | 1000000 |
| YourAuntDebbie |                4 | 1000000 |
| YourAuntDebbie |                5 | 1000000 |
| YourAuntDebbie |                6 |       0 |
+----------------+------------------+---------+

Inilah sesi XE yang saya gunakan untuk melihat kunci mana yang perlu dibangun kembali indeks:

CREATE EVENT SESSION Locks
    ON SERVER
    ADD EVENT sqlserver.lock_acquired
    ( SET collect_resource_description = ( 1 )
     ACTION ( sqlserver.sql_text )
     WHERE (   sqlserver.equal_i_sql_unicode_string(sqlserver.database_name, N'Crap')
               AND package0.equal_uint64(sqlserver.session_id, ( 61 )))),
    ADD EVENT sqlserver.lock_released
    ( SET collect_resource_description = ( 1 )
     ACTION ( sqlserver.sql_text )
     WHERE (   sqlserver.database_name = N'Crap'
               AND sqlserver.session_id = ( 61 )))
    ADD TARGET package0.event_file
    ( SET filename = N'c:\temp\Locks' )
    WITH ( MAX_MEMORY = 4096KB,
           EVENT_RETENTION_MODE = ALLOW_SINGLE_EVENT_LOSS,
           MAX_DISPATCH_LATENCY = 30 SECONDS,
           MAX_EVENT_SIZE = 0KB,
           MEMORY_PARTITION_MODE = NONE,
           TRACK_CAUSALITY = ON,
           STARTUP_STATE = OFF );
GO

Dengan itu, saya dapat membangun kembali partisi saya, dan kemudian menggali ke dalam XE.

ALTER EVENT SESSION Locks ON SERVER STATE = START;

ALTER INDEX ix_whatever ON dbo.YourAuntDebbie REBUILD PARTITION = 1 WITH (ONLINE = OFF);
GO 

ALTER INDEX ix_whatever ON dbo.YourAuntDebbie REBUILD PARTITION = 2 WITH (ONLINE = OFF);
GO 

ALTER INDEX ix_whatever ON dbo.YourAuntDebbie REBUILD PARTITION = 3 WITH (ONLINE = OFF);
GO 

ALTER INDEX ix_whatever ON dbo.YourAuntDebbie REBUILD PARTITION = 4 WITH (ONLINE = OFF);
GO 

ALTER INDEX ix_whatever ON dbo.YourAuntDebbie REBUILD PARTITION = 5 WITH (ONLINE = OFF); 
GO 

ALTER INDEX ix_whatever ON dbo.YourAuntDebbie REBUILD PARTITION = 6 WITH (ONLINE = OFF);
GO 

ALTER EVENT SESSION Locks ON SERVER STATE = STOP;

Sekarang, saya akan menempatkan peristiwa merobek-robek acara XE di akhir, karena itu cukup jelek, dan tidak ada alasan untuk membuat semua orang duduk melewatinya untuk melihat hasilnya. Saya akan menggunakan hasil partisi pertama sebagai contoh, tetapi mereka hampir identik di semua 6 partisi, bahkan yang kosong.

Saya membatasi hasil pembaruan hanya untuk mengunci level objek. Ini adalah satu-satunya yang kami pedulikan.

   +---------------+-------------------------+----------------+--------------+-------+------------------+--------+
|   EventName   |        EventDate        |   ObjectName   | ResourceType | Mode  | PARTITIONREBUILT | Events |
+---------------+-------------------------+----------------+--------------+-------+------------------+--------+
| lock_acquired | 2017-10-03 13:21:14.554 | YourAuntDebbie | OBJECT       | SCH_M | PARTITION = 1    |      1 |
| lock_acquired | 2017-10-03 13:21:14.554 | YourAuntDebbie | OBJECT       | SCH_S | PARTITION = 1    |      1 |
| lock_released | 2017-10-03 13:21:14.554 | YourAuntDebbie | OBJECT       | SCH_S | PARTITION = 1    |      1 |
| lock_acquired | 2017-10-03 13:21:14.603 | YourAuntDebbie | OBJECT       | S     | PARTITION = 1    |      6 |
| lock_acquired | 2017-10-03 13:21:14.603 | YourAuntDebbie | OBJECT       | SCH_S | PARTITION = 1    |     30 |
| lock_released | 2017-10-03 13:21:14.603 | YourAuntDebbie | OBJECT       | SCH_S | PARTITION = 1    |     24 |
| lock_released | 2017-10-03 13:21:14.867 | YourAuntDebbie | OBJECT       | SCH_M | PARTITION = 1    |      1 |
+---------------+-------------------------+----------------+--------------+-------+------------------+--------+

Dari apa yang dapat saya katakan, untuk setiap partisi , SCH-Mkunci diambil pada awal indeks membangun kembali, dan dirilis pada akhir ON THE TABLE .

Misalnya, jika saya menjalankan pembangunan kembali satu partisi dalam transaksi:

BEGIN TRAN

ALTER INDEX ix_whatever ON dbo.YourAuntDebbie REBUILD PARTITION = 1 WITH (ONLINE = OFF);

--ROLLBACK

Dan kemudian di jendela SSMS lain:

SELECT *
FROM dbo.YourAuntDebbie AS yad
WHERE yad.Id = 6000000
AND 1 = (SELECT 1)

Pilih diblokir sampai saya membunuh pembangunan kembali. Ketika selesai, rencana kueri menunjukkan penghapusan partisi yang terjadi , jadi hanya partisi 1 yang dibangun kembali yang memengaruhi seluruh tabel.

Semoga ini membantu!

Sekarang inilah kode merobek-robek sesi XE yang mengerikan:

    CREATE TABLE #Locks
       (
         ID INT IDENTITY(1, 1) NOT NULL PRIMARY KEY CLUSTERED,
         WaitsXML XML 
       );

INSERT  #Locks
        ( WaitsXML )
SELECT    CONVERT(XML, event_data) AS TargetData
FROM      sys.fn_xe_file_target_read_file( 'c:\temp\Locks*.xel', NULL, NULL, NULL);

WITH locks
AS ( SELECT l.WaitsXML.value('(/event/@name)[1]', 'VARCHAR(128)') AS EventName,
            l.WaitsXML.value('(/event/@timestamp)[1]', 'DATETIME2(3)') AS EventDate,
            l.WaitsXML.value('(event/data[@name="object_id"]/value)[1]', 'NUMERIC') AS ObjectId,
            l.WaitsXML.value('(event/data[@name="resource_type"]/text)[1]', 'VARCHAR(128)') AS ResourceType,
            l.WaitsXML.value('(event/data[@name="mode"]/text)[1]', 'VARCHAR(128)') AS Mode,
            l.WaitsXML.value('(event/action[@name="sql_text"]/value)[1]', 'VARCHAR(128)') AS SQLText,
            l.WaitsXML
     FROM   #Locks AS l )
SELECT   locks.EventName,
         locks.EventDate,
         ISNULL(OBJECT_NAME(locks.ObjectId), 'Unknown') AS ObjectName,
         locks.ResourceType,
         locks.Mode,
         SUBSTRING(
             locks.SQLText,
             CHARINDEX('PARTITION', locks.SQLText),
             CHARINDEX('WITH', locks.SQLText, CHARINDEX('PARTITION', locks.SQLText))
             - CHARINDEX('PARTITION', locks.SQLText)) AS PARTITIONREBUILT,
         COUNT(*) AS Events
FROM     locks
WHERE    OBJECT_NAME(locks.ObjectId) = 'YourAuntDebbie'
         --OR OBJECT_NAME(locks.ObjectId) IS NULL
GROUP BY ISNULL(OBJECT_NAME(locks.ObjectId), 'Unknown'),
         SUBSTRING(
             locks.SQLText,
             CHARINDEX('PARTITION', locks.SQLText),
             CHARINDEX('WITH', locks.SQLText, CHARINDEX('PARTITION', locks.SQLText))
             - CHARINDEX('PARTITION', locks.SQLText)),
         locks.EventName,
         locks.EventDate,
         locks.ResourceType,
         locks.Mode
ORDER BY locks.EventDate;

Erik Darling
sumber

Indeks Offline Dibangun Kembali pada Tabel yang Dipartisi

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