RE: Log a warning in pg_createsubscriber for max_slot_wal_keep_size

Dear Shubham,

Thanks for updating the patch. Few comments.

```
+#include "common/int.h" /* include for strtoi64 */
```

I could build the source code without the inclusion. Can you remove?

```
+ max_slot_wal_keep_size = strtoi64(PQgetvalue(res, 0, 6), NULL, 0);
+
+ /* use strtoi64 to convert the string result to a 64-bit integer */
+ if (max_slot_wal_keep_size == 0 && errno != 0)
+ {
+ /* handle conversion error */
+ pg_log_error("Failed to convert max_slot_wal_keep_size to int64");
+ }
```

I'm not sure the error handling is really needed. pg_dump also uses the function and it does
not have such handlings.

```
+ pg_log_debug("publisher: max_slot_wal_keep_size: %ld",
+ max_slot_wal_keep_size);
```

IIUC, "%ld" does not always represent int64 format. Since it is a debug message, isn't it enough to
use INT64_FORMAT macro?

```
+# Configure 'max_slot_wal_keep_size = 1' on the publisher and
+# reload configuration
+$node_p->append_conf('postgresql.conf', 'max_slot_wal_keep_size = 1');
+$node_p->reload;
```

Can you use 'max_slot_wal_keep_size = 10MB' or something to test the handling is correct?

Best regards,
Hayato Kuroda
FUJITSU LIMITED