In running the insert test to compare current develop with my log-wrlsn-thread branch and running a script to run it in several various settings, I'm seeing a read error about 20% of the time on both branches. It seems to happen primarily when I have the wiredTigerConcurrentWriteTransactions set to 8, 16 or 32. I have not seen it when it is set to 64 or (the default) 128. The develop change set is a95b150645ffe and log-wrlsn-thread was forked from develop a week ago at changeset b6e6433166d. So this is not introduced in the last couple of days.

The error is:

file:WiredTiger.wt, session.checkpoint: WiredTiger.wt read error: failed to read 4096 bytes at offset 53248: WT_ERROR: non-specific WiredTiger error

I'll start investigating the metadata file once my script finishes.