Pivotal Knowledge Base


"Header checksum does not match" an error for Append-Only tables

Note: This article is only applicable when a user upgrades to a higher version of Pivotal Greenplum and then downgrades to below to, when checksum was introduced.


  • Pivotal Greenplum (GPDB) 4.2.x, 4.3.x
  • OS RHEL 6.x


Append only tables are inaccessible by the users and result with the following error.

Error Message:

Header checksum does not match. Expected 0xAA2A471 and found 0x7421918B (cdbappendonlystorageread.c:849) (seg0 slice1 sdw1:40000 pid=6567) (cdbdisp.c:1525)
Append-Only storage Small Content header: smallcontent_bytes_0_3 0x19011C0F, smallcontent_bytes_4_7 0xCAC01DBA, headerKind = 1, executorBlockKind = 1, rowCount = 71, usingChecksums = true, header checksum 0xAA2A471, block checksum 0x28FAC5BD, dataLength 32342, compressedLength 7610, overallBlockLen 7632


Checksum storage is introduced in GPDB After upgrading to or higher, if the cluster is downgraded to a lower version, the checksum feature does not work and is likely to throw the above error.

Please refer to the documentation for more information: Greenplum Database 4.3.4 Release Notes.

Troubleshooting Steps

  1. Verify data is inserted to the Append-Only (AO) tables after downgrading.
  2. Turn checksum off and run a select on the table to check if it works:
set gp_appendonly_verify_block_checksums=false;
  1. Check /usr/local to confirm if there are any newer versions of Greenplum (higher than installed.


Check if the cluster has been recently downgraded from or to a lower version. If yes, then upgrade the cluster back to GPDB or higher. 

Additional Reference


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