Re: synchronized_standby_slots behavior inconsistent with quorum-based synchronous replication

Please find a few comments on June8 version fo patches:

1)
patch001:

SYNC_REP_DEFAULT: do we need to give one-line comment for this
somewhere as unlike PRIORITY and QUORUM, it is not self-explanatory.

patch002:
2)
It is better to avoid mentioning it as 'synchronized standby slots'.
We can make it as 'synchronized_standby_slots' in below comments:

+ /* Parse the synchronized standby slots configuration */

+ * Report problem states for synchronized standby slots that prevented the

3)
For these error-messages too, we need to mention GUC name to give
better clarity.

+ GUC_check_errmsg("number of synchronized standby slots (%d) must not
exceed the number of unique listed slots (%d)",
+ syncrep_parse_result->num_sync,
+ syncrep_parse_result->nmembers);

How about:
GUC_check_errcode(ERRCODE_INVALID_PARAMETER_VALUE);
GUC_check_errmsg("invalid value for parameter \"%s\: synchronization
requirement (%d) exceeds the number of unique listed slots (%d)",
"synchronized_standby_slots",
syncrep_parse_result->num_sync,
syncrep_parse_result->nmembers);

Or
GUC_check_errmsg("invalid value for parameter \"%s\: required number
of synchronized standby slots (%d) exceeds the number of unique listed
slots (%d)",
"synchronized_standby_slots",
syncrep_parse_result->num_sync,
syncrep_parse_result->nmembers);

3)
+ GUC_check_errmsg("number of synchronized standby slots (%d) must be
greater than zero",
+ syncrep_parse_result->num_sync)

How about:
GUC_check_errcode(ERRCODE_INVALID_PARAMETER_VALUE);
GUC_check_errmsg("invalid value for parameter \"%s\: required number
of synchronized standby slots (%d) must be greater than zero",
"synchronized_standby_slots",
syncrep_parse_result->num_sync);

---

Or, better yet, we can split the messages and details for both, example:

GUC_check_errcode(ERRCODE_INVALID_PARAMETER_VALUE);
GUC_check_errmsg("invalid value for parameter \"%s\",
"synchronized_standby_slots");
GUC_check_errdetail("The required number of synchronized standby slots
(%d) exceeds the number of unique listed slots (%d)",
syncrep_parse_result->num_sync,
syncrep_parse_result->nmembers);)

4)
+ReportUnavailableSyncStandbySlots(SyncStandbySlotsStateInfo * slot_states

We can get rid of space before slot_states. I think pgindent might
have put it in my patch. Sorry for the trouble.

5)
003:
- wait_for_all = (required == synchronized_standby_slots_config->nslotnames);
+ wait_for_all =
+ (synchronized_standby_slots_config->syncrep_method == SYNC_REP_DEFAULT);

This change can be moved to 002, right?

thanks
Shveta