scrolling and wrapping

[dlax]

As noticed in #239, and described in more details in #257, scrolling is broken when queries are wrapped.

At the moment, I don't see any good solution to this issue: changes from #257 look very strange to me (the list of processes shrinking while one scrolls down and then suddenly being reset upon wrap around).

So I've looked at what htop does:

• there does not seem to be any wrapping of process commands
• but one can use right/left arrows to see the line completely
• and there is a "w" key which displays the complete command of selected process in a dedicated window and wrapped so that everything is visible in the screen (at least horizontally)

Should we do the same in pg_activity?

That would mean drop the various wrapping options (command line flags and key bindings). But it seems to me that having the complete query displayed in a dedicated window could be interesting.

Thoughts?

[blogh]

I honestly am not fond of the wrapping thing and disable it.

[blogh]

I like the way htop does it.

It would be cool if we could "find" a little more space on the screen to display more of the unwrapped query.

Maybe having a switch to hide the ["cpu%" "mem%" "Read/s" "Write/s"] would do ?

Or a key to circle between displaying :

• ["cpu%" "mem%" "Read/s" "Write/s"].
• ["Waiting" "state" "IOW"]
• both (as it is now)

[dlax]

I like the idea of cycling through a subset of columns.

[blogh]

A quick readable summary of the available display modes in pg_activity :

• -w1 = TRUNCATED

PID    DATABASE                      APP             USER           CLIENT   CPU% MEM%   READ/s  WRITE/s     TIME+          Waiting  IOW              state   Query                          
105855 benches_are_nice          pgbench         postgres            local    0.9  0.5       0B  140.18K  0.249216    transactionid    N             active   UPDATE pgbench_tellers SET tbal
105850 benches_are_nice          pgbench         postgres            local    1.4  0.5       0B  193.21K  0.151634            tuple    N             active   UPDATE pgbench_tellers SET tbal
105875 benches_are_nice          pgbench         postgres            local    1.0  0.5       0B  162.91K  0.124041    transactionid    N             active   UPDATE pgbench_tellers SET tbal

• -w2 = FULL

PID    DATABASE                      APP             USER           CLIENT   CPU% MEM%   READ/s  WRITE/s     TIME+          Waiting  IOW              state   Query                          
105833 benches_are_nice          pgbench         postgres            local    0.0  0.5       0B       0B  0.204960    transactionid    N             active   UPDATE pgbench_tellers SET
tbalance = tbalance + -1075 WHERE tid = 3;
105878 benches_are_nice          pgbench         postgres            local    0.0  0.5       0B       0B  0.153246    transactionid    N             active   UPDATE pgbench_tellers SET
tbalance = tbalance + 532 WHERE tid = 2;
105861 benches_are_nice          pgbench         postgres            local    0.0  0.5       0B       0B  0.139701    transactionid    N             active   UPDATE pgbench_tellers SET
tbalance = tbalance + -2103 WHERE tid = 5;

• -w3 = INDENTED

PID    DATABASE                      APP             USER           CLIENT   CPU% MEM%   READ/s  WRITE/s     TIME+          Waiting  IOW              state   Query                          
105877 benches_are_nice          pgbench         postgres            local    0.0  0.5       0B       0B  0.193395            tuple    N             active   UPDATE pgbench_tellers SET
                                                                                                                                                              tbalance = tbalance + 275 WHERE
                                                                                                                                                              tid = 2;
105880 benches_are_nice          pgbench         postgres            local    0.0  0.5       0B       0B  0.140569    transactionid    N             active   UPDATE pgbench_tellers SET
                                                                                                                                                              tbalance = tbalance + 302 WHERE
                                                                                                                                                              tid = 5;
105834 benches_are_nice          pgbench         postgres            local    0.0  0.5       0B       0B  0.130835    transactionid    N             active   UPDATE pgbench_tellers SET
                                                                                                                                                              tbalance = tbalance + -3552
                                                                                                                                                              WHERE tid = 2;

In my opinion :

• -w2 makes the output unreadable.
• -w3 works nicely with little queries, but with a big query it's a nightmare also. (plus the screen space for the query is too short)

[gleu]

I like the way htop does it (at least, what you said it did).

-w1, -w2, and -w3 are great too. They sound like good options to have.

[Krysztophe]

Easy answer: implement all options , as different people will like different things

I personally am rather neutral, as I don't try to read complex queries in pg_activity, the beginning is usually enough to identify them and see what's running and what is blocking. I could change my mind though.