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DBCC - Chain Linkage Problem

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eicastic1
Starting Member

2 Posts

Posted - 2005-08-31 : 14:53:49

I'm having a problem where I see consistency errors in my databases on a regular basis (at least twice a week).

I have several databases running on the same instance of SQL Server. During any given week, at least one of the databases will show consistency errors. At times, more than one at the same time will show these errors. These have odd effects on queries, sometimes making a SELECT (for instance) that should run in 5 seconds have to be killed after running for over an hour.

I'm running SQL Server 2000, version 8.00.194. The host OS is Windows 2000 with the latest service pack. RAID 5 is the storage solution.

Below are two DBCC outputs from different databases on the same machine. They are slightly different in that one starts out with "Parent node for page was not encountered"; and the other with "Page is missing a reference from previous page".

My hardware guys assure me there is no hardware failure going. I don't see anything that would suggest there is one in any of the event logs or in the Dell OpenManage system checks.

These DBCC errors are repairable without data loss, yet the databases have to be taken down to single user mode to do so (unacceptable during the day). But at the same time, certain operations in the database become impossible to perform when these errors crop up (such as the aforementioned infinite SELECT problem).

Any help in diagnosing why these pop up, or how to prevent them would be greatly appreciated.

The DBCC outputs:
-----------------------------------------
dbcc checkdb('ValidValues') with no_infomsgs
==========
Server: Msg 8978, Level 16, State 1, Line 1
Table error: Object ID 926626344, index ID 3. Page (1:10921) is missing a reference from previous page (1:75359). Possible chain linkage problem.
Server: Msg 8976, Level 16, State 1, Line 1
Table error: Object ID 926626344, index ID 3. Page (1:75354) was not seen in the scan although its parent (1:75424) and previous (1:75352) refer to it. Check any previous errors.
Server: Msg 8980, Level 16, State 1, Line 1
Table error: Object ID 926626344, index ID 3. Index node page (1:75424), slot 19 refers to child page (1:75355) and previous child (1:75354), but they were not encountered.
Server: Msg 8980, Level 16, State 1, Line 1
Table error: Object ID 926626344, index ID 3. Index node page (1:75424), slot 20 refers to child page (1:75356) and previous child (1:75355), but they were not encountered.
Server: Msg 8980, Level 16, State 1, Line 1
Table error: Object ID 926626344, index ID 3. Index node page (1:75424), slot 21 refers to child page (1:75357) and previous child (1:75356), but they were not encountered.
Server: Msg 8980, Level 16, State 1, Line 1
Table error: Object ID 926626344, index ID 3. Index node page (1:75424), slot 22 refers to child page (1:75358) and previous child (1:75357), but they were not encountered.
Server: Msg 8980, Level 16, State 1, Line 1
Table error: Object ID 926626344, index ID 3. Index node page (1:75424), slot 23 refers to child page (1:75359) and previous child (1:75358), but they were not encountered.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 926626344, index ID 5. Parent node for page (1:10931) was not encountered.
Server: Msg 8979, Level 16, State 1, Line 1
Table error: Object ID 926626344, index ID 5. Page (1:10932) is missing references from parent (unknown) and previous (page (1:75671)) nodes. Possible bad root entry in sysindexes.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 926626344, index ID 5. Parent node for page (1:10933) was not encountered.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 926626344, index ID 5. Parent node for page (1:10934) was not encountered.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 926626344, index ID 5. Parent node for page (1:10937) was not encountered.
Server: Msg 8979, Level 16, State 1, Line 1
Table error: Object ID 926626344, index ID 5. Page (1:10940) is missing references from parent (unknown) and previous (page (0:0)) nodes. Possible bad root entry in sysindexes.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 926626344, index ID 5. Parent node for page (1:10941) was not encountered.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 926626344, index ID 5. Parent node for page (1:75664) was not encountered.
Server: Msg 8980, Level 16, State 1, Line 1
Table error: Object ID 926626344, index ID 5. Index node page (0:0), slot 0 refers to child page (1:75665) and previous child (0:0), but they were not encountered.
Server: Msg 8981, Level 16, State 1, Line 1
Table error: Object ID 926626344, index ID 5. The next pointer of (1:75664) refers to page (1:75666). Neither (1:75666) nor its parent were encountered. Possible bad chain linkage.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 926626344, index ID 5. Parent node for page (1:75673) was not encountered.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 926626344, index ID 5. Parent node for page (1:75674) was not encountered.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 926626344, index ID 5. Parent node for page (1:75675) was not encountered.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 926626344, index ID 5. Parent node for page (1:75676) was not encountered.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 926626344, index ID 5. Parent node for page (1:75705) was not encountered.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 926626344, index ID 5. Parent node for page (1:75706) was not encountered.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 926626344, index ID 5. Parent node for page (1:75707) was not encountered.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 926626344, index ID 5. Parent node for page (1:75708) was not encountered.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 926626344, index ID 5. Parent node for page (1:75737) was not encountered.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 926626344, index ID 5. Parent node for page (1:75738) was not encountered.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 926626344, index ID 5. Parent node for page (1:75739) was not encountered.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 926626344, index ID 5. Parent node for page (1:75740) was not encountered.
CHECKDB found 0 allocation errors and 29 consistency errors in table 'Company' (object ID 926626344).
CHECKDB found 0 allocation errors and 29 consistency errors in database 'ValidValues'.
repair_rebuild is the minimum repair level for the errors found by DBCC CHECKDB (ValidValues ).

-----------------------------------------

dbcc checkdb('Revenue') with no_infomsgs
==========
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 2089058478, index ID 2. Parent node for page (1:110576) was not encountered.
Server: Msg 8980, Level 16, State 1, Line 1
Table error: Object ID 2089058478, index ID 2. Index node page (0:0), slot 0 refers to child page (1:110577) and previous child (0:0), but they were not encountered.
Server: Msg 8981, Level 16, State 1, Line 1
Table error: Object ID 2089058478, index ID 2. The next pointer of (1:110576) refers to page (1:110578). Neither (1:110578) nor its parent were encountered. Possible bad chain linkage.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 2089058478, index ID 2. Parent node for page (1:110585) was not encountered.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 2089058478, index ID 2. Parent node for page (1:110586) was not encountered.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 2089058478, index ID 2. Parent node for page (1:110587) was not encountered.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 2089058478, index ID 2. Parent node for page (1:110588) was not encountered.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 2089058478, index ID 2. Parent node for page (1:110617) was not encountered.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 2089058478, index ID 2. Parent node for page (1:110618) was not encountered.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 2089058478, index ID 2. Parent node for page (1:110619) was not encountered.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 2089058478, index ID 2. Parent node for page (1:110620) was not encountered.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 2089058478, index ID 2. Parent node for page (1:110649) was not encountered.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 2089058478, index ID 2. Parent node for page (1:110650) was not encountered.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 2089058478, index ID 2. Parent node for page (1:110651) was not encountered.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 2089058478, index ID 2. Parent node for page (1:110652) was not encountered.
Server: Msg 8979, Level 16, State 1, Line 1
Table error: Object ID 2089058478, index ID 2. Page (1:124495) is missing references from parent (unknown) and previous (page (1:110581)) nodes. Possible bad root entry in sysindexes.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 2089058478, index ID 2. Parent node for page (1:124512) was not encountered.
Server: Msg 8979, Level 16, State 1, Line 1
Table error: Object ID 2089058478, index ID 2. Page (1:124513) is missing references from parent (unknown) and previous (page (0:0)) nodes. Possible bad root entry in sysindexes.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 2089058478, index ID 2. Parent node for page (1:124521) was not encountered.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 2089058478, index ID 2. Parent node for page (1:124650) was not encountered.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 2089058478, index ID 2. Parent node for page (1:124651) was not encountered.
Server: Msg 8977, Level 16, State 1, Line 1
Table error: Object ID 2089058478, index ID 2. Parent node for page (1:125214) was not encountered.
CHECKDB found 0 allocation errors and 22 consistency errors in table 'Operational_Reporting' (object ID 2089058478).
CHECKDB found 0 allocation errors and 22 consistency errors in database 'Revenue'.
repair_rebuild is the minimum repair level for the errors found by DBCC CHECKDB (Revenue ).

ryanston
Microsoft SQL Server Product Team

89 Posts

Posted - 2005-08-31 : 18:52:57

The first thing I might suggest is that you upgrade to the latest service pack for SQL Server 2000. Given that you're running the release (RTM) version, it's hard to elminate any of the bugs that might have been fixed between RTM and SP4. The output from CHECKDB looks like an index build bug, so this is the first thing I'd do (after appropriate testing, of course :)).

Thanks,

----------------------
Ryan Stonecipher
Developer, Microsoft SQL Server Storage Engine, DBCC
(Legalese: This posting is provided "AS IS" with no warranties, and confers no rights.)

eicastic1
Starting Member

2 Posts

Posted - 2005-09-01 : 12:28:49

quote:
Originally posted by ryanston

The first thing I might suggest is that you upgrade to the latest service pack for SQL Server 2000. Given that you're running the release (RTM) version, it's hard to elminate any of the bugs that might have been fixed between RTM and SP4. The output from CHECKDB looks like an index build bug, so this is the first thing I'd do (after appropriate testing, of course :)).

Will do. I'll upgrade and keep an eye on it.

Thanks.

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