我有一个sql服务器,通过合并复制安装到运行sql CE的800个移动客户端.
服务器具有足够的资源,公司内外的业务流量足够多,客户端与服务器之间的复制一般都很好,但是我们无法追踪到间歇性的错误.
昨天我们需要在我们的主表中插入550条记录,唯一的触发器是标准的合并复制.
这个插件花费了14个小时,因为它与移动设备试图同步不断地陷入僵局.
有没有人有任何建议,我们如何可以避免插入锁和如何加快整个过程？
——更新—–
接下来的一些评论,我已经运行一个剖析器在一个单一的插入,我看到很多这样的事情
insert into dbo.MSmerge_current_partition_mappings with (rowlock) (publication_number,tablenick,rowguid,partition_id)
select distinct 1,mc.tablenick,mc.rowguid,v.partition_id
from dbo.MSmerge_contents mc with (rowlock)
JOIN dbo.[MSmerge_JEMProjectME_PromotionResource_PARTITION_VIEW] v with (rowlock)
ON mc.tablenick = 286358001
and mc.rowguid = v.[rowguid]
and mc.marker = @child_marker
and v.partition_id in (select partition_id from dbo.MSmerge_current_partition_mappings cpm with (rowlock) JOIN
dbo.MSmerge_contents mc2 with (rowlock)
ON cpm.rowguid = mc2.rowguid
and mc2.marker = @marker)
where not exists (select * from MSmerge_current_partition_mappings with (readcommitted,rowlock,readpast) where
publication_number = 1 and
tablenick = 286358001 and
rowguid = v.[rowguid] and
partition_id = v.partition_id)
对于许多表,我不是要插入…这可能是一个线索？
解决方法
我们最近在我们的系统中经历了与您的系统相似的行为.原因是msmerge_contents和msmsmerge_current_partition_mappings中的大量数据,我们注意到,通过查看sql Profiler中读取的行数可能是缺少的索引. (49 000 000读取一个简单的插入在一个表中似乎有点多)
CREATE NONCLUSTERED INDEX [IX_MSmerge_current_partition_mappings_PERF1] ON [dbo].[MSmerge_current_partition_mappings]
(
[partition_id] ASC
)
INCLUDE ( [rowguid])
CREATE NONCLUSTERED INDEX [IX_msmerge_contents_PERF1] ON [dbo].[MSmerge_contents]
(
[marker] ASC
)
INCLUDE ( [rowguid])
我希望这可以帮助你,它帮助我们将查询时间从5分钟降低到10秒.
– 几个小时后…
我的同事发现另一个指标进一步提高了75％的表现：
CREATE NONCLUSTERED INDEX [IX_MSmerge_current_partition_mappings_PERF2] ON [dbo].[MSmerge_current_partition_mappings]
(
[rowguid] ASC,[partition_id] ASC
)
识别缺失的索引
您可以使用以下脚本来识别缺失的索引,按预期的方式排序,最大程度地提高性能(有许多这样的脚本流行,这是从http://www.sherbaz.com/category/sqlserver/借来的)
SELECT sys.objects.name,(avg_total_user_cost * avg_user_impact) * (user_seeks + user_scans) AS Impact,'CREATE NONCLUSTERED INDEX ix_IndexName ON ' + sys.objects.name COLLATE DATABASE_DEFAULT + ' ( ' + IsNull(mid.equality_columns,'') + CASE WHEN mid.inequality_columns IS NULL
THEN ''
ELSE CASE WHEN mid.equality_columns IS NULL
THEN ''
ELSE ',' END + mid.inequality_columns END + ' ) ' + CASE WHEN mid.included_columns IS NULL
THEN ''
ELSE 'INCLUDE (' + mid.included_columns + ')' END + ';' AS CreateIndexStatement,mid.equality_columns,mid.inequality_columns,mid.included_columns
FROM sys.dm_db_missing_index_group_stats AS migs
INNER JOIN sys.dm_db_missing_index_groups AS mig ON migs.group_handle = mig.index_group_handle
INNER JOIN sys.dm_db_missing_index_details AS mid ON mig.index_handle = mid.index_handle AND mid.database_id = DB_ID()
INNER JOIN sys.objects WITH (nolock) ON mid.OBJECT_ID = sys.objects.OBJECT_ID
WHERE (migs.group_handle IN
(
SELECT TOP (500) group_handle
FROM sys.dm_db_missing_index_group_stats WITH (nolock)
ORDER BY (avg_total_user_cost * avg_user_impact) * (user_seeks + user_scans) DESC))
AND OBJECTPROPERTY(sys.objects.OBJECT_ID,'isusertable')=1
ORDER BY 2 DESC,3 DESC
