There is insufficient system memory in resource pool 'internal'

Question

SQL Server 2008 Linked Server and ad-hoc INSERTs cause a rapid memory leak which eventually causes the server to become non-responsive and ends with the following error:

Msg 701, Level 17, State 123, Server BRECK-PC\SQLEXPRESS, Line 2
There is insufficient system memory in resource pool 'internal' to run this 
query.

Location:        qxcntxt.cpp:1052
Expression:      cref == 0
SPID:            51
Process ID:      1880

The server remains non-responsive until SQL Server is restarted.

Software in use:

• Windows Vista Ultimate 64 bit build 6001 SP1

• Microsoft SQL Server 2008 (SP1) - 10.0.2734.0 (X64) Sep 11 2009 14:30:58 Copyright (c) 1988-2008 Microsoft Corporation Express Edition with Advanced Services (64-bit) on Windows NT 6.0 (Build 6001: Service Pack 1)

• SAOLEDB.11 driver from SQL Anywhere 11.0.1.2276

Setting max server memory (MB) to 2048 did not help.

Adding various -g values (e.g., -g256;) to the server Startup Parameters did not help.

Using DBCC FREESYSTEMCACHE ( 'ALL' ), DBCC FREESESSIONCACHE and DBCC FREEPROCCACHE did not help.

Installing the Cumnulative update package 4 to SQL Server 2008 Service Pack 1 did not help, even though it contained a fix to a memory leak symptom involving Linked Server usage.

Separating the SELECT ... ROW_NUMBER() OVER ... query from the INSERT did not help. Experimentation showed that the complex SELECT did not cause the memory leak, the INSERT did.

Changing the code to use the ad-hoc "INSERT INTO OPENROWSET" syntax instead of a linked server did not help; the code below shows the linked server usage.

The sysinternals.com Process Explore utility shows that the memory usage was associated with sqlserver.exe, not the DLLs used by the SQL Anywhere OLEDB driver SAOLEDB.11.

Note that the SQL Anywhere version of linked server (proxy tables) works OK, to "pull" 1.9 million rows from a SQL Server 2008 table to a SQL Anywhere 11 database in a single transaction. The logic shown here is an attempt to use the linked server feature to "push" the rows; same direction, different syntax.

The code follows; 4G of RAM is exhausted after three or four executions of the EXECUTE copy_mss_t2:

EXEC sys.sp_configure 
   N'show advanced options',  
   N'1'
GO

RECONFIGURE WITH OVERRIDE
GO

EXEC sys.sp_configure
   N'max server memory (MB)',
   N'2048'
GO

RECONFIGURE WITH OVERRIDE
GO

EXEC sys.sp_configure
   N'show advanced options',
   N'0'
GO

RECONFIGURE WITH OVERRIDE
GO
EXEC master.dbo.sp_MSset_oledb_prop
   N'SAOLEDB.11',
   N'AllowInProcess',
   1
GO

sp_addlinkedserver
   @server = 'mem',
   @srvproduct = 'SQL Anywhere OLE DB Provider',
   @provider = 'SAOLEDB.11',
   @datasrc = 'mem_PAVILION2'
GO

EXEC master.dbo.sp_serveroption
   @server=N'mem',
   @optname=N'rpc',
   @optvalue=N'true'
GO

EXEC master.dbo.sp_serveroption
   @server=N'mem',
   @optname=N'rpc out',
   @optvalue=N'true'
GO

sp_addlinkedsrvlogin
   @rmtsrvname = 'mem',
   @useself = 'false',
   @locallogin = NULL,
   @rmtuser = 'dba',
   @rmtpassword = 'sql'
GO

CREATE PROCEDURE copy_mss_t2
   @from_row            BIGINT,
   @to_row              BIGINT,
   @rows_copied_count   BIGINT OUTPUT
AS

   SELECT *
     INTO #t
     FROM ( SELECT *,
                   ROW_NUMBER()
                      OVER ( ORDER BY sample_set_number,
                                      connection_number )
                   AS t2_row_number
             FROM mss_t2 ) AS ordered_mss_t2
    WHERE ordered_mss_t2.t2_row_number BETWEEN @from_row AND @to_row;

   SELECT @rows_copied_count = COUNT(*)
     FROM #t;

INSERT INTO mem..dba.sa_t2
SELECT sampling_id,
       sample_set_number,
       connection_number,
       blocker_owner_table_name,
       blocker_lock_type,
       blocker_owner_name,
       blocker_table_name,
       blocker_reason,
       blocker_row_identifier,
       current_engine_version,
       page_size,
       ApproximateCPUTime,
       BlockedOn,
       BytesReceived,
       BytesSent,
       CacheHits,
       CacheRead,
   "Commit",
   DiskRead,
   DiskWrite,
   FullCompare,
   IndAdd,
   IndLookup,
   Isolation_level,
   LastReqTime,
   LastStatement,
   LockCount,
   LockName,
   LockTableOID,
   LoginTime,
   LogWrite,
   Name,
   NodeAddress,
   Prepares,
   PrepStmt,
   QueryLowMemoryStrategy,
   QueryOptimized,
   QueryReused,
   ReqCountActive,
   ReqCountBlockContention,
   ReqCountBlockIO,
   ReqCountBlockLock,
   ReqCountUnscheduled,
   ReqStatus,
   ReqTimeActive,
   ReqTimeBlockContention,
   ReqTimeBlockIO,
   ReqTimeBlockLock,
   ReqTimeUnscheduled,
   ReqType,
   RequestsReceived,
   Rlbk,
   RollbackLogPages,
   TempFilePages,
   TransactionStartTime,
   UncommitOp,
   Userid,
   previous_ApproximateCPUTime,
   interval_ApproximateCPUTime,
   previous_Commit,
   interval_Commit,
   previous_Rlbk,
   interval_Rlbk
  FROM #t;

GO

DECLARE @rows_copied_count BIGINT
EXECUTE copy_mss_t2 1110001, 1120000, @rows_copied_count OUTPUT
SELECT @rows_copied_count
GO

EXECUTE create_linked_server
GO

DECLARE @rows_copied_count BIGINT
EXECUTE copy_mss_t2 1120001, 1130000, @rows_copied_count OUTPUT
SELECT @rows_copied_count
GO

EXECUTE create_linked_server
GO

Here is the SQL Server source table, containing about 1G of data in 1.9 million rows:

CREATE TABLE mss_t2 (
   sampling_id                       BIGINT NOT NULL,
   sample_set_number                 BIGINT NOT NULL,
   connection_number                 BIGINT NOT NULL,
   blocker_owner_table_name          VARCHAR ( 257 ) NULL,
   blocker_lock_type                 VARCHAR ( 32 ) NULL,
   blocker_owner_name                VARCHAR ( 128 ) NULL,
   blocker_table_name                VARCHAR ( 128 ) NULL,
   blocker_reason                    TEXT NULL,
   blocker_row_identifier            VARCHAR ( 32 ) NULL,
   current_engine_version            TEXT NOT NULL,
   page_size                         INTEGER NOT NULL,
   ApproximateCPUTime                DECIMAL ( 30, 6 ) NULL,
   BlockedOn                         BIGINT NULL,
   BytesReceived                     BIGINT NULL,
   BytesSent                         BIGINT NULL,
   CacheHits                         BIGINT NULL,
   CacheRead                         BIGINT NULL,
   "Commit"                          BIGINT NULL,
   DiskRead                          BIGINT NULL,
   DiskWrite                         BIGINT NULL,
   FullCompare                       BIGINT NULL,
   IndAdd                            BIGINT NULL,
   IndLookup                         BIGINT NULL,
   Isolation_level                   BIGINT NULL,
   LastReqTime                       TEXT NOT NULL DEFAULT '1900-01-01',
   LastStatement                     TEXT NULL,
   LockCount                         BIGINT NULL,
   LockName                          BIGINT NULL,
   LockTableOID                      BIGINT NULL,
   LoginTime                         TEXT NOT NULL DEFAULT '1900-01-01',
   LogWrite                          BIGINT NULL,
   Name                              VARCHAR ( 128 ) NULL,
   NodeAddress                       TEXT NULL,
   Prepares                          BIGINT NULL,
   PrepStmt                          BIGINT NULL,
   QueryLowMemoryStrategy            BIGINT NULL,
   QueryOptimized                    BIGINT NULL,
   QueryReused                       BIGINT NULL,
   ReqCountActive                    BIGINT NULL,
   ReqCountBlockContention           BIGINT NULL,
   ReqCountBlockIO                   BIGINT NULL,
   ReqCountBlockLock                 BIGINT NULL,
   ReqCountUnscheduled               BIGINT NULL,
   ReqStatus                         TEXT NULL,
   ReqTimeActive                     DECIMAL ( 30, 6 ) NULL,
   ReqTimeBlockContention            DECIMAL ( 30, 6 ) NULL,
   ReqTimeBlockIO                    DECIMAL ( 30, 6 ) NULL,
   ReqTimeBlockLock                  DECIMAL ( 30, 6 ) NULL,
   ReqTimeUnscheduled                DECIMAL ( 30, 6 ) NULL,
   ReqType                           TEXT NULL,
   RequestsReceived                  BIGINT NULL,
   Rlbk                              BIGINT NULL,
   RollbackLogPages                  BIGINT NULL,
   TempFilePages                     BIGINT NULL,
   TransactionStartTime              TEXT NOT NULL DEFAULT '1900-01-01',
   UncommitOp                        BIGINT NULL,
   Userid                            VARCHAR ( 128 ) NULL,
   previous_ApproximateCPUTime       DECIMAL ( 30, 6 ) NOT NULL DEFAULT 0.0,
   interval_ApproximateCPUTime       AS ( COALESCE ( "ApproximateCPUTime", 0 ) - previous_ApproximateCPUTime ),
   previous_Commit                   BIGINT NOT NULL DEFAULT 0,
   interval_Commit                   AS  ( COALESCE ( "Commit", 0 ) - previous_Commit ),
   previous_Rlbk                     BIGINT NOT NULL DEFAULT 0,
   interval_Rlbk                     AS  ( COALESCE ( Rlbk, 0 ) - previous_Rlbk ) )

Here is the target table in SQL Anywhere 11:

CREATE TABLE sa_t2 (
   sampling_id                       BIGINT NOT NULL,
   sample_set_number                 BIGINT NOT NULL,
   connection_number                 BIGINT NOT NULL,
   blocker_owner_table_name          VARCHAR ( 257 ) NULL,
   blocker_lock_type                 VARCHAR ( 32 ) NULL,
   blocker_owner_name                VARCHAR ( 128 ) NULL,
   blocker_table_name                VARCHAR ( 128 ) NULL,
   blocker_reason                    TEXT NULL,
   blocker_row_identifier            VARCHAR ( 32 ) NULL,
   current_engine_version            TEXT NOT NULL,
   page_size                         INTEGER NOT NULL,
   ApproximateCPUTime                DECIMAL ( 30, 6 ) NULL,
   BlockedOn                         BIGINT NULL,
   BytesReceived                     BIGINT NULL,
   BytesSent                         BIGINT NULL,
   CacheHits                         BIGINT NULL,
   CacheRead                         BIGINT NULL,
   "Commit"                          BIGINT NULL,
   DiskRead                          BIGINT NULL,
   DiskWrite                         BIGINT NULL,
   FullCompare                       BIGINT NULL,
   IndAdd                            BIGINT NULL,
   IndLookup                         BIGINT NULL,
   Isolation_level                   BIGINT NULL,
   LastReqTime                       TEXT NOT NULL DEFAULT '1900-01-01',
   LastStatement                     TEXT NULL,
   LockCount                         BIGINT NULL,
   LockName                          BIGINT NULL,
   LockTableOID                      BIGINT NULL,
   LoginTime                         TEXT NOT NULL DEFAULT '1900-01-01',
   LogWrite                          BIGINT NULL,
   Name                              VARCHAR ( 128 ) NULL,
   NodeAddress                       TEXT NULL,
   Prepares                          BIGINT NULL,
   PrepStmt                          BIGINT NULL,
   QueryLowMemoryStrategy            BIGINT NULL,
   QueryOptimized                    BIGINT NULL,
   QueryReused                       BIGINT NULL,
   ReqCountActive                    BIGINT NULL,
   ReqCountBlockContention           BIGINT NULL,
   ReqCountBlockIO                   BIGINT NULL,
   ReqCountBlockLock                 BIGINT NULL,
   ReqCountUnscheduled               BIGINT NULL,
   ReqStatus                         TEXT NULL,
   ReqTimeActive                     DECIMAL ( 30, 6 ) NULL,
   ReqTimeBlockContention            DECIMAL ( 30, 6 ) NULL,
   ReqTimeBlockIO                    DECIMAL ( 30, 6 ) NULL,
   ReqTimeBlockLock                  DECIMAL ( 30, 6 ) NULL,
   ReqTimeUnscheduled                DECIMAL ( 30, 6 ) NULL,
   ReqType                           TEXT NULL,
   RequestsReceived                  BIGINT NULL,
   Rlbk                              BIGINT NULL,
   RollbackLogPages                  BIGINT NULL,
   TempFilePages                     BIGINT NULL,
   TransactionStartTime              TEXT NOT NULL DEFAULT '1900-01-01',
   UncommitOp                        BIGINT NULL,
   Userid                            VARCHAR ( 128 ) NULL,
   previous_ApproximateCPUTime       DECIMAL ( 30, 6 ) NOT NULL DEFAULT 0.0,
   interval_ApproximateCPUTime       DECIMAL ( 30, 6 ) NOT NULL COMPUTE ( COALESCE ( "ApproximateCPUTime", 0 ) - previous_ApproximateCPUTime ),
   previous_Commit                   BIGINT NOT NULL DEFAULT 0,
   interval_Commit                   BIGINT NOT NULL COMPUTE ( COALESCE ( "Commit", 0 ) - previous_Commit ),
   previous_Rlbk                     BIGINT NOT NULL DEFAULT 0,
   interval_Rlbk                     BIGINT NOT NULL COMPUTE ( COALESCE ( Rlbk, 0 ) - previous_Rlbk ),
   PRIMARY KEY ( sample_set_number, connection_number ) );

Eufemiaeugen

I have added the CREATE TABLE statements for the source and target tables. Further experimentation indicates that the variety of data types might be the cause of the memory leak; e.g., multiple TEXT columns, 30-digit DECIMALs, computed AS columns and so on. My PROFOUND APOLOGIES for leaving out the DDL from the original problem statement... kinda unfair. – Eufemiaeugen

Preliminary indications are that having multiple TEXT columns in the source table causes the SQL Server memory leak. Changing all but one TEXT column to VARCHAR seems to do the trick. A full test is up to 250,000 rows with zero RAM increase; I'll wait for it to finish, then put together a small reproducible. – Eufemiaeugen

Answer 1

Don't you need to empty the temp table #t after each iteration? i.e. add a TRUNCATE TABLE #t at the end of your procedure? I think that temp table #t exists until your session ends, not until the stored procedure ends. SELECT INTO just appends to the existing #t, but does not replace it.

Another thing would be to use a permanent table not something stored in tempdb #tables.

Purchasable

An excellent observation! FWIW the total space required for all 1.9 million rows is about 1G, whereas the memory leak uses up several G of RAM after only a few thousand rows are processed... so I am not hopeful that it has anything to do with the temp table (which was added after the memory leak was first noticed). However, like I said earlier, at this point any and all suggestions are welcome. – Eufemiaeugen

Of all the answers, including the one that was deleted, I like yours the best, so I'm giving you the bonus. – Eufemiaeugen

Of course, it's not the actual answer (see my answer below), but it's kind of silly to offer a bonus, get everyone interested in my problem, and then yank the bonus away! – Eufemiaeugen

If anyone wants to upvote the question, that would be appreciated... it's a real bug in SQL Server 2008, requires hard reboot. I think the downvote was childish, but that's just me :) – Eufemiaeugen

The workaround is working just fine. I'm writing an article about different ways to load data into an in-memory database, and I can just mention in passing that one technique doesn't work for long strings. Or three techniques: Linked Server, OPENROWSET and SSIS... I am testing the latter two to confirm. Three other techniques work fine: BCP with LOAD TABLE, MobiLink and SQL Anywhere's proxy tables. – Eufemiaeugen

Answer 2

The problem is using a linked server via the SQL Anywhere 11.0.1 provider SAOLEDB.11 to insert data into a target column declared as larger than VARCHAR ( 8000 ). Here is a simplified reproducible:

-- Overview: SQL Server 2008 suffers from a fatal memory leak
--    if an attempt is made to use a linked server and the 
--    SAOLEDB.11 provicer to copy data from SQL Server
--    to a SQL Anywhere 11.0.1 table that contains a single column
--    larger than VARCHAR ( 8000 ); i.e, a VARCHAR ( 8000 ) target
--    column is OK but VARCHAR ( 8001 ) is not. The actual string 
--    length is not an issue, nor is the fact that the SQL Server
--    column is declared as TEXT. The memory leak is faster if
--    there is more than one target column larger than VARCHAR ( 8000 ).
--    The server computer freezes and must be rebooted.
-- Msg 701, Level 17, State 123, Server BRECK-PC\SQLEXPRESS, Line 2
-- There is insufficient system memory in resource pool 'internal' to run this
-- query.
-- Location:        qxcntxt.cpp:1052
-- Expression:      cref == 0
-- SPID:            52
-- Process ID:      2044

---------------------------------------------------------
-- SQL ANYWHERE 11 on target computer
---------------------------------------------------------

-- Target:
-- HP Pavilion laptop, 4GHz Pentium 4, 2G RAM
-- Windows XP SP2
-- SQL Anywhere 11.0.1.2276

---------------------------------------------------------
-- Windows commands used to create and start in-memory database

/*
"%SQLANY11%\bin32\dbinit.exe"^
  mem.db

"%SQLANY11%\bin32\dbspawn.exe" -f^
  "%SQLANY11%\bin32\dbsrv11.exe"^
  -im nw^
  -o dbsrv11_log.txt^
  mem.db 

"%SQLANY11%\bin32\dbisql.com"^
  -c "ENG=mem;DBN=mem;UID=dba;PWD=sql;CON=mem-1"
*/

---------------------------------------------------------
-- Create target table with one single "long" column.

BEGIN
   DROP TABLE sa_target;
   EXCEPTION WHEN OTHERS THEN
END;

CREATE TABLE sa_target (
   primary_key      INTEGER NOT NULL PRIMARY KEY,
   string_column_1  VARCHAR ( 8001 ) NOT NULL );

---------------------------------------------------------
--- SQL SERVER 2008 on source (server) computer
---------------------------------------------------------

-- Server:
-- Desktop with Intel Core 2 Quad Q9450 2.66Ghz 4G RAM
-- Windows Vista Ultimate 64 bit build 6001 SP1
-- SQL Server 2008 Express 64 Service Pack 1 with cumulative update package 4:
--    Microsoft SQL Server 2008 (SP1) - 10.0.2734.0 (X64)   Sep 11 2009 14:30:58   
--    Copyright (c) 1988-2008 Microsoft Corporation  Express Edition with    
--    Advanced Services (64-bit) on Windows NT 6.0 <X64>    
--    (Build 6001: Service Pack 1) 
-- SAOLEDB.11 driver from SQL Anywhere 11.0.1.2276

---------------------------------------------------------
-- Windows command used to start osql.exe

/*
"c:\Program Files\Microsoft SQL Server\100\Tools\Binn\osql.exe"^
  -d main^
  -I^
  -l 10^
  -P j68Fje9#fyu489^
  -S BRECK-PC\SQLEXPRESS^
  -U sa
*/

---------------------------------------------------------
-- Create database.

USE master
GO

BEGIN TRY
   DROP DATABASE main;
END TRY
BEGIN CATCH
END CATCH;
GO

CREATE DATABASE main
ON PRIMARY
( NAME = main_dat,
   FILENAME = 'E:\data\main\main.mdf',
   SIZE = 2GB,
   FILEGROWTH = 200MB )
LOG ON
( NAME = 'main_log',
   FILENAME = 'E:\data\main\main.ldf',
   SIZE = 2GB,
   FILEGROWTH = 200MB )
GO

----------------------------------------------------------------------------
-- Configure SAOLEDB.11 provider.

USE master
go 

-- SAOLEDB.11 provider dlls registered via these Windows commands:
--    regsvr32 dboledb11.dll
--    regsvr32 dboledba11.dll

EXEC master.dbo.sp_MSset_oledb_prop N'SAOLEDB.11', N'AllowInProcess', 1
GO

-- If the following statement produces this message, it probably means 
-- that 'DisallowAdHocAccess' is already set to zero for SAOLEDB.11:
--
-- RegDeleteValue() returned error 2, 'The system cannot find the file specified.'

EXEC master.dbo.sp_MSset_oledb_prop N'SAOLEDB.11', N'DisallowAdHocAccess', 0
GO

----------------------------------------------------------------------------
-- THIS SECTION WAS NOT RUN.
-- Set up for OPENROWSET usage.
-- NOT REQUIRED for required for Linked Server usage.

USE master
GO

sp_configure 'show advanced options', 1
GO

RECONFIGURE
GO

sp_configure 'Ad Hoc Distributed Queries', 1
GO

RECONFIGURE
GO

----------------------------------------------------------------------------
-- Set up Linked Server usage.

USE main
GO

BEGIN TRY
   EXEC sp_droplinkedsrvlogin 
      @rmtsrvname = 'mem',
      @locallogin = NULL  
END TRY
BEGIN CATCH
END CATCH 
GO

BEGIN TRY
   EXEC sp_dropserver
      @server = 'mem'
END TRY
BEGIN CATCH
END CATCH 
GO

EXEC sp_addlinkedserver
   @server = 'mem',
   @srvproduct = 'SQL Anywhere OLE DB Provider',
   @provider = 'SAOLEDB.11',
   @datasrc = 'mem_PAVILION2' 
GO

EXEC master.dbo.sp_serveroption 
   @server=N'mem', 
   @optname=N'rpc', 
   @optvalue=N'true' 
GO

EXEC master.dbo.sp_serveroption 
   @server=N'mem', 
   @optname=N'rpc out', 
   @optvalue=N'true' 
GO

EXEC sp_addlinkedsrvlogin 
   @rmtsrvname = 'mem', 
   @useself = 'false', 
   @locallogin = NULL, 
   @rmtuser = 'dba', 
   @rmtpassword = 'sql' 
GO

----------------------------------------------------------------------------
-- Create and fill source table with 1 million rows.

USE main
GO

BEGIN TRY
   DROP TABLE mss_source; 
END TRY
BEGIN CATCH
END CATCH 
GO

CREATE TABLE mss_source ( 
   primary_key      INTEGER NOT NULL PRIMARY KEY,
   string_column_1  TEXT NOT NULL )
GO

BEGIN
   DECLARE @primary_key INTEGER 
   SELECT @primary_key = 1
   BEGIN TRANSACTION
   WHILE @primary_key <= 1000000 
   BEGIN
      INSERT mss_source VALUES (
         @primary_key,
         REPLICATE ( 'Some test data. ', 2 ) )
      SELECT @primary_key = @primary_key + 1
   END
   COMMIT
END
GO

SELECT COUNT(*) FROM mss_source
GO

-- 1000000

---------------------------------------------------------
-- Copy data to target table.

SELECT CURRENT_TIMESTAMP
GO

INSERT INTO mem..dba.sa_target 
SELECT * 
  FROM mss_source
GO

SELECT CURRENT_TIMESTAMP
GO

---------------------------------------------------------
-- Test 1 - Code as shown above.
-- FAILED
-- 
-- Started at 2009-10-12 10:06:33.393
-- 
-- A slow server memory leak began immediately.
-- The initial target insert rate was about 2000 rows per second.
-- Server RAM usage reached 3.82 GB, Physical Memory: 95%, Page File 16236M / 16288M
-- The server display became frozen.
-- The server became unresponsive to mouse input.
-- The target insert rate dropped below 1000 rows per second, but inserts continued.
-- The copy process reached 937,817 rows inserted on the target.
-- This dialog box appeared on the server: "Your computer is low on memory"
-- Eventually, the process failed, and this message appeared in the osql.exe window:
-- 
-- Msg 701, Level 17, State 123, Server BRECK-PC\SQLEXPRESS, Line 2
-- There is insufficient system memory in resource pool 'internal' to run this
-- query.
-- Location:        qxcntxt.cpp:1052
-- Expression:      cref == 0
-- SPID:            52
-- Process ID:      2044
-- 
-- Failed at 2009-10-12 10:22:21.817
-- The server disk I/O light remained lit without interruption.
-- The server required a hard reboot.

---------------------------------------------------------
-- Test 2 - Code as shown above, except for VARCHAR ( 8000 ).
-- SUCCESSFUL 

BEGIN
   DROP TABLE sa_target;
   EXCEPTION WHEN OTHERS THEN
END;

CREATE TABLE sa_target (
   primary_key      INTEGER NOT NULL PRIMARY KEY,
   string_column_1  VARCHAR ( 8000 ) NOT NULL );

-- Started at 2009-10-12 10:41:46.427
-- There was some slight initial growth in RAM usage on the server.
-- Server RAM usage stabilized at 1.40 GB, Physical Memory: 35%, Page File 1560M / 8352M
-- The target insert rate remained about 2000 rows per second throughout.
-- Finished OK at 2009-10-12 10:50:52.240

---------------------------------------------------------
-- Test 3 - Repeat Test 2
-- SUCCESSFUL 

-- Started at 2009-10-12 10:53:38.350
-- No further RAM usage growth on the server.
-- Finished OK at 2009-10-12 11:02:10.457

Eufemiaeugen

Answer 3

I had a similar problem, my code contains usage of a simple #temp table in a loop, that caused this and I replaced with a permanent table.

Seems to be working.

Thanks Naveen

Adorl

Answer 4

Instead of using Temp Tables, can you try using Variable tables?

eg.

DECLARE @ResultTable TABLE (TableId INT PRIMARY KEY, ... etc)

INSERT INTO @ResultTable
SELECT TableId, ....
FROM mss_t2 

... etc. ...

Ellon

The temp table was introduced after the memory leak first surfaced... it was added as a workaround attempt. Experimentation shows that the leak does not occur until after the temp table is filled, when the INSERT to the linked server table begins. HOWEVER, anything is worth trying, at this point! Thanks! – Eufemiaeugen

Answer 5

You could try running the insert in batches instead of the whole dataset at once.

Pastern

"You could try running the insert in batches instead of the whole dataset at once." - that's exactly what the code is doing, copying batches of only 10,000 rows at a time: EXECUTE copy_mss_t2 1110001, 1120000, ... - that's exactly why the complex SELECT was used, to gather up tiny batches. I have considered writing a single-row-FETCH and INSERT loop but the Kludge Faktor is rather extreme... relational databases are supposed to handle sets. – Eufemiaeugen

Try a smaller batch, not all the way to one. Keep lowering the batch size until it works. Or alternatively try moving the records through an SSIS package instead of a linked server. – Pastern

Experiments show the memory leak is not related to the batch size; in particular, the memory leak is orders of magnitude larger than the amount of data being transferred. Also, the whole purpose of this code is to use linked server functionality, for the purposes of an article on the subject. Thanks for the suggestion about SSIS, I will give it a go (but, sadly, "In SQL Server Express, the option to save the package that the wizard creates is not available.") – Eufemiaeugen

@HLGEM: I wouldn't bother: answers are marked down if they don't solve the issue even of they aren't wrong – Elsy

SSIS failed much faster, after fewer than 3000 rows made it across. A Google search indicates that 0x8007000E probably means memory exhausted, and Task Manager supports that (from 1G to 4G RAM used in a few seconds). I suspect SSIS is using the same logic as Linked Server. Error 0xc0202009: Data Flow Task 1: SSIS Error Code DTS_E_OLEDBERROR. An OLE DB error has occurred. Error code: 0x8007000E. – Eufemiaeugen

@gbn: Sorry to hurt your feelings, won't do that again! – Eufemiaeugen

@Breck Did you get to the bottom of this? I have the same error, but I am pulling data from Sybase to SQL 2008 via linked server. The SQL server gives the same error after 15 minutes of running a query to pull data. – Misreckon