RE: Suggestion to add --continue-client-on-abort option to pgbench

Dear Ikeda-san,

Thanks for updating the patch!

> 1. I should've also set benchmarking_option_set. I've modified it accordingly.

Confirmed it has been fixed. Thanks.

> 2. The exit-on-abort option and continue-on-error option are mutually exclusive.
> Therefore, I've updated the patch to throw a FATAL error when two options are
> set simultaneously. Corresponding explanation was also added.
> (I'm wondering the name of parameter should be continue-on-abort so that users
> understand the two option are mutually exclusive.)

Make sense, +1.

Here are new comments.

01. build failure
According to the cfbot [1], the documentation cannot be built. IIUC </para> seemed
to be missed here:
```
+ <para>
+ Note that this option can not be used together with
+ <option>--exit-on-abort</option>.
+ </listitem>
+ </varlistentry>
```

02. patch separation
How about separating the patch series like:

0001 - contains option handling and retry part, and documentation
0002 - contains accumulation/reporting part
0003 - contains tests.

I hope above style is more helpful for reviewers.

03. documentation
```
+ Note that this option can not be used together with
+ <option>--exit-on-abort</option>.
```

I feel we should add the similar description in `exit-on-abort` part.

04. documentation
```
+ Client rolls back the failed transaction and starts a new one when its
+ transaction fails due to the reason other than the deadlock and
+ serialization failure. This allows all clients specified with -c option
+ to continuously apply load to the server, even if some transactions fail.
```

I feel the description contains bit redundant part and misses the default behavior.
How about:
```
<para>
Clients survive when their transactions are aborted, and they continue
their run. Without the option, clients exit when transactions they run
are aborted.
</para>
<para>
Note that serialization failures or deadlock failures do not abort the
client, so they are not affected by this option.
See <xref linkend="failures-and-retries"/> for more information.
</para>
```

05. StatsData
```
+ * When continue-on-error option is specified,
+ * failed (the number of failed transactions) =
+ * 'other_sql_failures' (they got a error when continue-on-error option
+ * was specified).
```

Let me confirm one point; can serialization_failures and deadlock_failures be
counted when continue-on-error is true? If so, the comment seems not correct for me.
The formula can be 'serialization_failures' + 'deadlock_failures' + 'deadlock_failures'
in the case.

06. StatsData
Another point; can other_sql_failures be counted when the continue-on-error is NOT
specified? I feel it should be...

06. usage()
Added line is too long. According to program_help_ok(), the output by help should
be less than 80.

07.
Please run pgindent/pgperltidy, I got some diffs.

[1]: https://cirrus-ci.com/task/5210061275922432

Best regards,
Hayato Kuroda
FUJITSU LIMITED