A session renewed from a token issued before sessions were tracked has
an id derived from that token, and the renewal inserts it only when no
row by that id exists. The nightly purge deleted revoked rows straight
away, so the next request with the still valid old token inserted the
session again as an active one and got a fresh tracked token with a new
lifetime. A logout, an ended session or a sign out of the others held
only until the purge ran.
The purge now deletes expired rows only, and a revoked row stays until
its own expiry. A derived row is recorded with an expiry no earlier
than the old token's, so by the time it goes the old token is refused
by its signature check anyway.
Maurice
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