Re: [EXTERNAL] Support load balancing in libpq

Hi,

> So I think it should be:
>
> ```
> if (conn->addr == NULL && conn->naddr != 0)
> ```
>
> [...]
>
> I will take a look at v16 now.

The code coverage could be slightly better.

In v16-0001:

```
+ ret = store_conn_addrinfo(conn, addrlist);
+ pg_freeaddrinfo_all(hint.ai_family, addrlist);
+ if (ret)
+ goto error_return; /* message already logged */
```

The goto path is not test-covered.

In v16-0002:

```
+ }
+ else
+ conn->load_balance_type = LOAD_BALANCE_DISABLE;
```

The else branch is never executed.

```
if (ret)
goto error_return; /* message already logged */

+ /*
+ * If random load balancing is enabled we shuffle the addresses.
+ */
+ if (conn->load_balance_type == LOAD_BALANCE_RANDOM)
+ {
+ /*
+ * This is the "inside-out" variant of the Fisher-Yates shuffle
[...]
+ */
+ for (int i = 1; i < conn->naddr; i++)
+ {
+ int j =
pg_prng_uint64_range(&conn->prng_state, 0, i);
+ AddrInfo temp = conn->addr[j];
+
+ conn->addr[j] = conn->addr[i];
+ conn->addr[i] = temp;
+ }
+ }
```

Strangely enough the body of the for loop is never executed either.
Apparently only one address is used and there is nothing to shuffle?

Here is the exact command I used to build the code coverage report:

```
git clean -dfx && meson setup --buildtype debug -Db_coverage=true
-Dcassert=true -DPG_TEST_EXTRA="kerberos ldap ssl load_balance"
-Dldap=disabled -Dssl=openssl -Dtap_tests=enabled
-Dprefix=/home/eax/projects/pginstall build && ninja -C build &&
PG_TEST_EXTRA=1 meson test -C build && ninja -C build coverage-html
```

I'm sharing this for the sake of completeness. I don't have a strong
opinion on whether we should bother with covering every new line of
code with tests.

Except for the named nitpicks v16 looks good to me.

--
Best regards,
Aleksander Alekseev