v0.10.2 - external reader causing high read io

[AskAlexSharov]

Hi. After switching to v0.10.2 we got several similar reports from different clients: 1 process writing, 1 process open db in read-only. Read process started causing heigh read IO. Something like 100% pageCache-miss (not getting better with time).

No docker, processes run under same user/group.

I didn’t really reproduced it yet.

[erthink]

Please clarify which the version you are switching from, i.e. which version there was no such issue(s)?

[AskAlexSharov]

From v0.10.1
OS: ubuntu 20.04
disk type: SSD

[erthink]

If this is really a regression, then I have no other ideas yet, except that it is caused by 7da64b7.
So I will partially revert it, since (in a worst case) this must not lead to any problems but just adds a few system calls when opening a DB.

[AskAlexSharov]

Confirm that d2cba98 solved problem