Senaste inläggen 

Taggar 

Logins     platsannons SQL utvecklare     connection     feedback     temp table     AcquireConnection     error     bugs     sp1     performance     SQL Server 2012     package load     2011     constraint     Säkerhet     resource governor     rebuild     HEAP     CU3     Trace Flag     data warehouse     SQL2008     login error     0xC0010014     2005     parameters     SQL Server     SSIS     sql 2008     Microsoft     undocumented procedures     sql browser     CMS     dbmail     parallelism     BOL     Datawarehouse     central management server     connect     Page life expectancy     SQL Denali     sql 2005     history     Techdays     security     #am_get_querystats     T-SQL     page splits     access denied     SQL server codename Denali     DTA     SSRS     DECIMAL     Extended Event     CU1     gratis verktyg     clean up     SSRS 2008     features     HADR     concatenation     Cluster     reorganize index     create index     XP_cmdshell     transactions     Business Intelligence     2000     profile     filter     Reports     2008     sp_MSForEachDB     function     CTE     0xC0202009     Activity Monitor     SSAS     CTP1     improve     virtuell

SQL Server mystery: Hekaton tables and Hekaton Procedures

Skrivet den 12 juni 2012 i T-SQL, SQL Server 2008, SQL Server 2008R2, SQL Server 2012, Level 500, SQL Server maintenance, Steinar Andersen, sv, en

Have you ever heard of Hekaton Tables and Hekaton Procedures in SQL Server? Neither had I until recently. And it seems neither have Google. I happened to stumble upon the mention of these mysterious object, and tried to find out more, but had no luck. But I wanted to share what I have seen of is so far, and ask you, the readers of our blog, if you might have some light to shed on this? If so, please comment on this blogpost.

To find the mention of Hekaton on your own SQL Server instance, run the following code:

select * from syscomments where text like '%hekaton%'

That should generate an output that indicates that sp_updatestats, sp_createstats and sp_recompile contains the word Hekaton.

The relevant lines of code are as follows:

from "sp_helptext sp_createstats":

   -- filter out local temp tables, Hekaton tables, and tables for which current user has no permissions

   -- Note that OBJECTPROPERTY returns NULL on type="IT" tables, thus we only call it on type='U' tables

   if (

      (@@fetch_status <> -2) and

      (substring(@tablename, 1, 1) <> '#') and -- temp tables

      ((@table_type<>'U') or (0 = OBJECTPROPERTY(@table_id, 'TableIsInMemory'))) and -- Hekaton table

from "sp_helptext sp_updatestats"

   -- filter out local temp tables and Hekaton tables

   -- Note that OBJECTPROPERTY returns NULL on type="IT" tables, thus we only call it on type='U' tables

   if ((@@fetch_status <> -2) and

      (substring(@table_name, 1, 1) <> '#') and  -- temp tables

      ((@table_type<>'U') or (0 = OBJECTPROPERTY(@table_id, 'TableIsInMemory')))) -- Hekaton tables

from "sp_helptext sp_recompile"

   -- Hekaton procedure cannot be recompiled

   -- Make them go through schema version bumping branch, which will fail

       ObjectProperty(@objid, 'ExecIsCompiledProc') = 0)

None of that really tells us exactly what Hekaton tables and Hekaton procedures are, but might give some clues. The undocumented OBJECTPROPERTY(@table_id, 'TableIsInMemory') call (another mystery...) seems to indicate that it could possibly be connected to memory, caching or even the old and removed feature of DBCC PINTABLE? That would be a real surprise in that case.

The comments tells us the following: Hekaton Procedures cannot be recompiled using sp_recompile Hekaton tables can not update or create stats using sp_updatestats and sp_createstats

I know that this is not much, but if you have more information about this little mystery, please comment it on this blogpost or mail me at firstname.lastname@sqlservice.se

 

Skriv en kommentar

  • Lookup SQL Server 2014 In Memory OLTP. Hekaton is the codemanme for this incarnation of in memory SQL database that is coming with SQL Server 2014

    By tester