KB-1419 KDB numbering goes negative

Symptom

KDB file numbering for one or more engines moves into the negatives. This may manifest in:

• the actual .kdb files on disk
• the checkpointing messages in the corresponding gw_ log
• the DB ID referenced in the corresponding db_ log

For example, if the process execution01 engine is the one in question, you may notice the following:

• A negative .kdb file in <APPIAN_HOME>/server/process/exec/01/gw1/: pe-2147483646.kdb.
• A reference in the gw_PX001 log: [PX001] INFO .a.gw.ssa "Server switchover to database ID -2147483646".
• A reference in the db_PX001 log: [PX001] {pe-2147483646.kdb ,4405}.

Cause

This issue can occur after improperly resetting a particular engine's KDBs or if extraneous KDB files are manually introduced.

Action

1. Shut down the engine with the negative KDB numbering.
2. Rename the negative KDB to a positive numbers, ensuring that the most recent KDB has the highest number.

Warning: Renaming .kdb files is not supported beyond what is documented in this article.

Affected Versions

Last Reviewed: November 2017