print MasterTermStartTime in ListAllTablets and show vitess_tablets

[deepthi]

Sample output:

$ vtctlclient ... ListAllTablets
zone1-0000000100 commerce 0 master localhost:15100 localhost:17100 [] 2020-04-30T20:30:47Z
zone1-0000000101 commerce 0 replica localhost:15101 localhost:17101 [] <null>
zone1-0000000102 commerce 0 rdonly localhost:15102 localhost:17102 [] <null>

zone1-0000000100 commerce 0 unknown localhost:15100 localhost:17100 [] 2020-05-01T04:35:35Z
zone1-0000000101 commerce 0 master localhost:15101 localhost:17101 [] 2020-05-01T04:36:47Z
zone1-0000000102 commerce 0 rdonly localhost:15102 localhost:17102 [] <null>

mysql> show vitess_tablets;
+-------+----------+-------+------------+---------+------------------+------------------+----------------------+
| Cell  | Keyspace | Shard | TabletType | State   | Alias            | Hostname         | MasterTermStartTime  |
+-------+----------+-------+------------+---------+------------------+------------------+----------------------+
| zone1 | commerce | 0     | MASTER     | SERVING | zone1-0000000100 | deepthi-ThinkPad | 2020-04-30T20:53:23Z |
| zone1 | commerce | 0     | REPLICA    | SERVING | zone1-0000000101 | deepthi-ThinkPad |                      |
| zone1 | commerce | 0     | RDONLY     | SERVING | zone1-0000000102 | deepthi-ThinkPad |                      |
+-------+----------+-------+------------+---------+------------------+------------------+----------------------+

Signed-off-by: deepthi deepthi@planetscale.com

[enisoc]

I think a lot of people may have scripts that awk the output of ListAllTablets, since it's specifically documented as being "awk-friendly" and the format has been stable for many years. If we change existing columns like this, we should make sure to surface this as an "action required" release note, if not a breaking change.

Alternatively, if we add new info as additional columns at the end, it should be backwards-compatible. Is there a reason we didn't want to do that?

[deepthi]

I think a lot of people may have scripts that awk the output of ListAllTablets, since it's specifically documented as being "awk-friendly" and the format has been stable for many years. If we change existing columns like this, we should make sure to surface this as an "action required" release note, if not a breaking change.

Alternatively, if we add new info as additional columns at the end, it should be backwards-compatible. Is there a reason we didn't want to do that?

Good point. The only reason for the chosen format was to keep the timestamp close to the tablet_type. We can change it and move it to the end.