You can run tpatrace 1 to see when the database was last reset.
# tpatrace 1
TPA Initialization Trace for System localhost Node 001-01
09/13/18 07:32:13 -------------------- PDE restarting TPA cycle = 17
09/13/18 07:32:13.77 (0/0 1188) ---- PDE starting.
09/13/18 07:32:13.77 (0/0 1188) State is START/BEGIN.
09/13/18 07:32:13.81 (0/0 1188) Set tpaminsynctimeout = 120
09/13/18 07:32:13.81 (0/0 1188) Set tpakilltimeout = 30
09/13/18 07:32:13.90 (0/0 1188) State is START/RECONCILE.
09/13/18 07:32:14.19 (0/0 1188) State is START/SETUP.
09/13/18 07:32:14.19 (0/0 1188) 1 node selected by reconcile.
09/13/18 07:32:14.19 (0/0 1188) 1 node defined in gdo.
09/13/18 07:32:14.19 (0/0 1188) State is START/NETCONFIG.
09/13/18 07:32:15.26 (0/0 1188) 1 node used (I am COORDINATOR).
09/13/18 07:32:15.26 (0/0 1188) Waiting for GDO setup... done in 0 seconds.
09/13/18 07:32:15.28 (0/0 1188) State is START/NETREADY.
09/13/18 07:32:15.28 (0/0 1188) Syncing... done in 0 seconds.
09/13/18 07:32:15.28 (0/0 1188) Syncing... done in 0 seconds.
09/13/18 07:32:15.28 (0/0 1188) Syncing... done in 0 seconds.
09/13/18 07:32:15.37 (0/0 1188) Syncing... done in 0 seconds.
09/13/18 07:32:15.37 (0/0 1188) State is START/GDOSYNC.
09/13/18 07:32:15.37 (0/0 1188) Syncing... done in 0 seconds.
09/13/18 07:32:16.15 (0/0 1188) Syncing... done in 0 seconds.
09/13/18 07:32:16.15 (0/0 1188) State is START/SYSGDOINIT.
09/13/18 07:32:16.15 (0/0 1188) Syncing... done in 0 seconds.
09/13/18 07:32:16.15 (0/0 1188) Syncing... done in 0 seconds.
09/13/18 07:32:16.15 (0/0 1188) Syncing... done in 0 seconds.
09/13/18 07:32:16.16 (0/0 1188) Syncing... done in 0 seconds.
09/13/18 07:32:16.16 (0/0 1188) Local system crashcount -> 0.
09/13/18 07:32:16.16 (0/0 1188) Syncing... done in 0 seconds.
09/13/18 07:32:16.16 (0/0 1188) Syncing... done in 0 seconds.
09/13/18 07:32:16.16 (0/0 1188) Syncing... done in 0 seconds.
09/13/18 07:32:16.16 (0/0 1188) Updating V2P GDO... done in 0 seconds.
09/13/18 07:32:16.16 (0/0 1188) Syncing... done in 0 seconds.
09/13/18 07:32:16.16 (0/0 1188) State is START/VPROCALLOC.
09/13/18 07:32:16.16 (0/0 1188) Updating V2P GDO... done in 0 seconds.
09/13/18 07:32:16.16 (0/0 1188) Syncing... done in 0 seconds.
09/13/18 07:32:16.16 (0/0 1188) State is START/FSGDEVINIT.
09/13/18 07:32:16.16 (0/0 1188) FSG cache needflush flag is cleared due to FSGDEVINIT: FSG restart.
09/13/18 07:32:16.16 (0/0 1188) Syncing... done in 0 seconds.
09/13/18 07:32:16.20 (0/0 1188) State is START/VPROCSTART.
09/13/18 07:32:16.21 (0/0 1188) Starting vproc in slot 1(0) 2(1) 3(30718) 4(30719) 5(22528) 6(26623) 7(28671)
09/13/18 07:32:16.22 (0/0 1188) Syncing... done in 0 seconds.
09/13/18 07:32:16.22 (0/0 1188) Updating V2P GDO... done in 0 seconds.
09/13/18 07:32:16.22 (0/0 1188) Syncing... done in 0 seconds.
09/13/18 07:32:16.22 (0/0 1188) State is START/TVSASTART.
09/13/18 07:32:17.36 (0/0 1188) TVSA initialization working(1)... working(1)... working(1)... working(1)... done.
09/13/18 07:32:18.38 (0/0 1188) Syncing... done in 0 seconds.
09/13/18 07:32:18.38 (0/0 1188) State is START/VPROCDONE.
09/13/18 07:32:18.41 (0/0 1188) Syncing... done in 0 seconds.
09/13/18 07:32:18.41 (0/0 1188) Updating CONTROL GDO... done in 0 seconds.
09/13/18 07:32:18.42 (0/0 1188) Syncing... done in 0 seconds.
09/13/18 07:32:18.42 (0/0 1188) Waiting for RSS setup... done in 0 seconds.
09/13/18 07:32:18.43 (0/0 1188) Syncing... done in 0 seconds.
09/13/18 07:32:18.43 (0/0 1188) State is START/STARTCNS.
09/13/18 07:32:18.47 (0/0 1188) Syncing... done in 0 seconds.
09/13/18 07:32:18.47 (0/0 1188) State is START/READY.
09/13/18 07:32:19.06 (0/0 1188) Syncing... done in 0 seconds.
09/13/18 07:32:19.06 (0/0 1188) State is START/STARTTPA.
09/13/18 07:32:19.91 (0/0 1188) Syncing... done in 0 seconds.
09/13/18 07:32:19.91 (0/0 1188) State is RUN/STARTED.
09/13/18 07:32:19.91 (0/0 1188) Crash count/ceiling = 0/3
09/13/18 07:32:19.91 (0/0 1188) PDE started in 6 seconds.