Re: postgres_fdw hint messages

[Nathan Bossart]

On Fri, Sep 16, 2022 at 03:54:53PM +0200, Peter Eisentraut wrote:
> I don't think we need a verb there at all.  I committed it without a verb.

Thanks!

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com

Re: postgres_fdw hint messages

[Peter Eisentraut]

On 13.09.22 21:02, Nathan Bossart wrote:

On Tue, Sep 13, 2022 at 08:32:43AM +0200, Peter Eisentraut wrote:

I notice that for column misspellings, the hint is phrased "Perhaps you
meant X." whereas here we have "Did you mean X?".  Let's make that uniform.


Good point.  I attached a new version of the patch that uses the column
phrasing.  I wasn't sure whether "reference" was the right word to use in
this context, but I used it for now for consistency with the column hints.
I think "specify" or "use" would work as well.


I don't think we need a verb there at all.  I committed it without a verb.

Re: postgres_fdw hint messages

[Nathan Bossart]

On Tue, Sep 13, 2022 at 08:32:43AM +0200, Peter Eisentraut wrote:
> I notice that for column misspellings, the hint is phrased "Perhaps you
> meant X." whereas here we have "Did you mean X?".  Let's make that uniform.

Good point.  I attached a new version of the patch that uses the column
phrasing.  I wasn't sure whether "reference" was the right word to use in
this context, but I used it for now for consistency with the column hints.
I think "specify" or "use" would work as well.

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com
>From f9e5d136214e2b55c0bcf0b7b8ec2485aab0e7ba Mon Sep 17 00:00:00 2001
From: Nathan Bossart 
Date: Fri, 2 Sep 2022 14:03:26 -0700
Subject: [PATCH v4 1/1] Adjust assorted hint messages that list all valid
 options.

Instead of listing all valid options, we now try to provide one
that looks similar.  Since this may be useful elsewhere, this
change introduces a new set of functions that can be reused for
similar purposes.
---
 contrib/dblink/dblink.c   | 27 +++---
 contrib/dblink/expected/dblink.out|  1 -
 contrib/file_fdw/expected/file_fdw.out|  2 -
 contrib/file_fdw/file_fdw.c   | 24 --
 .../postgres_fdw/expected/postgres_fdw.out|  3 +-
 contrib/postgres_fdw/option.c | 23 --
 src/backend/foreign/foreign.c | 26 --
 src/backend/utils/adt/varlena.c   | 82 +++
 src/include/utils/varlena.h   | 12 +++
 src/test/regress/expected/foreign_data.out|  6 +-
 10 files changed, 159 insertions(+), 47 deletions(-)

diff --git a/contrib/dblink/dblink.c b/contrib/dblink/dblink.c
index 3df3f9bbe9..8c26adb56c 100644
--- a/contrib/dblink/dblink.c
+++ b/contrib/dblink/dblink.c
@@ -2008,27 +2008,32 @@ dblink_fdw_validator(PG_FUNCTION_ARGS)
 		{
 			/*
 			 * Unknown option, or invalid option for the context specified, so
-			 * complain about it.  Provide a hint with list of valid options
-			 * for the context.
+			 * complain about it.  Provide a hint with a valid option that
+			 * looks similar, if there is one.
 			 */
-			StringInfoData buf;
 			const PQconninfoOption *opt;
+			const char *closest_match;
+			ClosestMatchState match_state;
+			bool		has_valid_options = false;
 
-			initStringInfo(&buf);
+			initClosestMatch(&match_state, def->defname, 4);
 			for (opt = options; opt->keyword; opt++)
 			{
 if (is_valid_dblink_option(options, opt->keyword, context))
-	appendStringInfo(&buf, "%s%s",
-	 (buf.len > 0) ? ", " : "",
-	 opt->keyword);
+{
+	has_valid_options = true;
+	updateClosestMatch(&match_state, opt->keyword);
+}
 			}
+
+			closest_match = getClosestMatch(&match_state);
 			ereport(ERROR,
 	(errcode(ERRCODE_FDW_OPTION_NAME_NOT_FOUND),
 	 errmsg("invalid option \"%s\"", def->defname),
-	 buf.len > 0
-	 ? errhint("Valid options in this context are: %s",
-			   buf.data)
-	 : errhint("There are no valid options in this context.")));
+	 has_valid_options ? closest_match ?
+	 errhint("Perhaps you meant to reference the option \"%s\".",
+			 closest_match) : 0 :
+	 errhint("There are no valid options in this context.")));
 		}
 	}
 
diff --git a/contrib/dblink/expected/dblink.out b/contrib/dblink/expected/dblink.out
index c7bde6ad07..14d015e4d5 100644
--- a/contrib/dblink/expected/dblink.out
+++ b/contrib/dblink/expected/dblink.out
@@ -897,7 +897,6 @@ $d$;
 CREATE USER MAPPING FOR public SERVER fdtest
   OPTIONS (server 'localhost');  -- fail, can't specify server here
 ERROR:  invalid option "server"
-HINT:  Valid options in this context are: user, password, sslpassword
 CREATE USER MAPPING FOR public SERVER fdtest OPTIONS (user :'USER');
 GRANT USAGE ON FOREIGN SERVER fdtest TO regress_dblink_user;
 GRANT EXECUTE ON FUNCTION dblink_connect_u(text, text) TO regress_dblink_user;
diff --git a/contrib/file_fdw/expected/file_fdw.out b/contrib/file_fdw/expected/file_fdw.out
index 261af1a8b5..36d76ba26c 100644
--- a/contrib/file_fdw/expected/file_fdw.out
+++ b/contrib/file_fdw/expected/file_fdw.out
@@ -166,7 +166,6 @@ ERROR:  invalid option "force_not_null"
 HINT:  There are no valid options in this context.
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (force_not_null '*'); -- ERROR
 ERROR:  invalid option "force_not_null"
-HINT:  Valid options in this context are: filename, program, format, header, delimiter, quote, escape, null, encoding
 -- force_null is not allowed to be specified at any foreign object level:
 ALTER FOREIGN DATA WRAPPER file_fdw OPTIONS (ADD force_null '*'); -- ERROR
 ERROR:  invalid option "force_null"
@@ -179,7 +178,6 @@ ERROR:  invalid option "force_null"
 HINT:  There are no valid options in this context.
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (force_null '*'); -- ERROR
 ERROR:  invalid option "force_null"
-HINT:  Valid options in this context are: filename, program, format, header, delimiter, quote,

Re: postgres_fdw hint messages

[Peter Eisentraut]

On 03.09.22 06:30, Nathan Bossart wrote:

On Fri, Sep 02, 2022 at 10:06:54PM -0400, Tom Lane wrote:

I think the distance limit of 5 is too loose though.  I see that
it accommodates examples like "passfile" for "password", which
seems great at first glance; but it also allows fundamentally
silly suggestions like "user" for "server" or "host" for "foo".
We'd need something smarter than Levenshtein if we want to offer
"passfile" for "password" without looking stupid on a whole lot
of other cases --- those words seem close, but they are close
semantically not textually.


Yeah, it's really only useful for simple misspellings, but IMO even that is
rather handy.

I noticed that the parse_relation.c stuff excludes matches where more than
half the characters are different, so I added that here and lowered the
distance limit to 4.  This seems to prevent the silly suggestions (e.g.,
"host" for "foo") while retaining the more believable ones (e.g.,
"passfile" for "password"), at least for the small set of examples covered
in the tests.


I think this code is compact enough and the hints it produces are 
reasonable, so I think we could go with it.


I notice that for column misspellings, the hint is phrased "Perhaps you 
meant X." whereas here we have "Did you mean X?".  Let's make that uniform.

Re: postgres_fdw hint messages

[Nathan Bossart]

On Fri, Sep 02, 2022 at 10:06:54PM -0400, Tom Lane wrote:
> I think the distance limit of 5 is too loose though.  I see that
> it accommodates examples like "passfile" for "password", which
> seems great at first glance; but it also allows fundamentally
> silly suggestions like "user" for "server" or "host" for "foo".
> We'd need something smarter than Levenshtein if we want to offer
> "passfile" for "password" without looking stupid on a whole lot
> of other cases --- those words seem close, but they are close
> semantically not textually.

Yeah, it's really only useful for simple misspellings, but IMO even that is
rather handy.

I noticed that the parse_relation.c stuff excludes matches where more than
half the characters are different, so I added that here and lowered the
distance limit to 4.  This seems to prevent the silly suggestions (e.g.,
"host" for "foo") while retaining the more believable ones (e.g.,
"passfile" for "password"), at least for the small set of examples covered
in the tests.

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com
>From 1ce0024357343cf4c1436cd74ed20e304d673762 Mon Sep 17 00:00:00 2001
From: Nathan Bossart 
Date: Fri, 2 Sep 2022 14:03:26 -0700
Subject: [PATCH v3 1/1] Adjust assorted hint messages that list all valid
 options.

Instead of listing all valid options, we now try to provide one
that looks similar.  Since this may be useful elsewhere, this
change introduces a new set of functions that can be reused for
similar purposes.
---
 contrib/dblink/dblink.c   | 26 +++---
 contrib/dblink/expected/dblink.out|  1 -
 contrib/file_fdw/expected/file_fdw.out|  2 -
 contrib/file_fdw/file_fdw.c   | 23 --
 .../postgres_fdw/expected/postgres_fdw.out|  3 +-
 contrib/postgres_fdw/option.c | 22 +++--
 src/backend/foreign/foreign.c | 25 --
 src/backend/utils/adt/varlena.c   | 82 +++
 src/include/utils/varlena.h   | 12 +++
 src/test/regress/expected/foreign_data.out|  6 +-
 10 files changed, 155 insertions(+), 47 deletions(-)

diff --git a/contrib/dblink/dblink.c b/contrib/dblink/dblink.c
index e323fdd0e6..5e2d7b4c70 100644
--- a/contrib/dblink/dblink.c
+++ b/contrib/dblink/dblink.c
@@ -2008,27 +2008,31 @@ dblink_fdw_validator(PG_FUNCTION_ARGS)
 		{
 			/*
 			 * Unknown option, or invalid option for the context specified, so
-			 * complain about it.  Provide a hint with list of valid options
-			 * for the context.
+			 * complain about it.  Provide a hint with a valid option that
+			 * looks similar, if there is one.
 			 */
-			StringInfoData buf;
 			const PQconninfoOption *opt;
+			const char *closest_match;
+			ClosestMatchState match_state;
+			bool		has_valid_options = false;
 
-			initStringInfo(&buf);
+			initClosestMatch(&match_state, def->defname, 4);
 			for (opt = options; opt->keyword; opt++)
 			{
 if (is_valid_dblink_option(options, opt->keyword, context))
-	appendStringInfo(&buf, "%s%s",
-	 (buf.len > 0) ? ", " : "",
-	 opt->keyword);
+{
+	has_valid_options = true;
+	updateClosestMatch(&match_state, opt->keyword);
+}
 			}
+
+			closest_match = getClosestMatch(&match_state);
 			ereport(ERROR,
 	(errcode(ERRCODE_FDW_OPTION_NAME_NOT_FOUND),
 	 errmsg("invalid option \"%s\"", def->defname),
-	 buf.len > 0
-	 ? errhint("Valid options in this context are: %s",
-			   buf.data)
-	 : errhint("There are no valid options in this context.")));
+	 has_valid_options ? closest_match ?
+	 errhint("Did you mean \"%s\"?", closest_match) : 0 :
+	 errhint("There are no valid options in this context.")));
 		}
 	}
 
diff --git a/contrib/dblink/expected/dblink.out b/contrib/dblink/expected/dblink.out
index c7bde6ad07..14d015e4d5 100644
--- a/contrib/dblink/expected/dblink.out
+++ b/contrib/dblink/expected/dblink.out
@@ -897,7 +897,6 @@ $d$;
 CREATE USER MAPPING FOR public SERVER fdtest
   OPTIONS (server 'localhost');  -- fail, can't specify server here
 ERROR:  invalid option "server"
-HINT:  Valid options in this context are: user, password, sslpassword
 CREATE USER MAPPING FOR public SERVER fdtest OPTIONS (user :'USER');
 GRANT USAGE ON FOREIGN SERVER fdtest TO regress_dblink_user;
 GRANT EXECUTE ON FUNCTION dblink_connect_u(text, text) TO regress_dblink_user;
diff --git a/contrib/file_fdw/expected/file_fdw.out b/contrib/file_fdw/expected/file_fdw.out
index 261af1a8b5..36d76ba26c 100644
--- a/contrib/file_fdw/expected/file_fdw.out
+++ b/contrib/file_fdw/expected/file_fdw.out
@@ -166,7 +166,6 @@ ERROR:  invalid option "force_not_null"
 HINT:  There are no valid options in this context.
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (force_not_null '*'); -- ERROR
 ERROR:  invalid option "force_not_null"
-HINT:  Valid options in this context are: filename, program, format, header, delimiter, quote, escape, null, encoding
 -- force_null is not a

Re: postgres_fdw hint messages

[Tom Lane]

Michael Paquier  writes:
> On Fri, Sep 02, 2022 at 02:26:09PM -0700, Nathan Bossart wrote:
>> * I chose a Levenshtein distance of 5 as the threshold of closeness for the
>> hint messages.  This felt lenient, but it should hopefully still filter out
>> some of the more ridiculous suggestions.  However, it's still little more
>> than a wild guess, so if folks think the threshold needs to be higher or
>> lower, I'd readily change it.

> Hmm.  FWIW I would tend toward simplifying all this code and just drop
> all the hints rather than increasing the dependency to more
> levenshtein calculations in those error code paths, which is what
> Peter E has posted.

Personally I'm not a huge fan of this style of hint either.  However,
people seem to like the ones for misspelled column names, so I'm
betting there will be a majority in favor of this one too.

I think the distance limit of 5 is too loose though.  I see that
it accommodates examples like "passfile" for "password", which
seems great at first glance; but it also allows fundamentally
silly suggestions like "user" for "server" or "host" for "foo".
We'd need something smarter than Levenshtein if we want to offer
"passfile" for "password" without looking stupid on a whole lot
of other cases --- those words seem close, but they are close
semantically not textually.

regards, tom lane

Re: postgres_fdw hint messages

[Michael Paquier]

On Fri, Sep 02, 2022 at 02:26:09PM -0700, Nathan Bossart wrote:
> Here is a new patch.  Two notes:
> 
> * I considered whether to try to unite this new functionality with the
> existing stuff in parse_relation.c, but the existing code looked a bit too
> specialized.
> 
> * I chose a Levenshtein distance of 5 as the threshold of closeness for the
> hint messages.  This felt lenient, but it should hopefully still filter out
> some of the more ridiculous suggestions.  However, it's still little more
> than a wild guess, so if folks think the threshold needs to be higher or
> lower, I'd readily change it.

Hmm.  FWIW I would tend toward simplifying all this code and just drop
all the hints rather than increasing the dependency to more
levenshtein calculations in those error code paths, which is what
Peter E has posted.
--
Michael


signature.asc
Description: PGP signature

Re: postgres_fdw hint messages

[Nathan Bossart]

On Thu, Sep 01, 2022 at 04:31:20PM -0700, Nathan Bossart wrote:
> On Thu, Sep 01, 2022 at 07:08:49PM -0400, Tom Lane wrote:
>> (1) there probably needs to be some threshold of closeness, so we don't
>> offer "foobar" when the user wrote "huh"
> 
> Agreed.
> 
>> (2) there are several places doing this now, and there will no doubt
>> be more later, so we need to try to abstract the logic so it can be
>> shared.
> 
> Will do.

Here is a new patch.  Two notes:

* I considered whether to try to unite this new functionality with the
existing stuff in parse_relation.c, but the existing code looked a bit too
specialized.

* I chose a Levenshtein distance of 5 as the threshold of closeness for the
hint messages.  This felt lenient, but it should hopefully still filter out
some of the more ridiculous suggestions.  However, it's still little more
than a wild guess, so if folks think the threshold needs to be higher or
lower, I'd readily change it.

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com
>From c3c7793daf7e6b225605a44a1faead2f7678bca3 Mon Sep 17 00:00:00 2001
From: Nathan Bossart 
Date: Fri, 2 Sep 2022 14:03:26 -0700
Subject: [PATCH v2 1/1] Adjust assorted hint messages that list all valid
 options.

Instead of listing all valid options, we now try to provide one
that looks similar.  Since this may be useful elsewhere, this
change introduces a new set of functions that can be reused for
similar purposes.
---
 contrib/dblink/dblink.c   | 26 +++---
 contrib/dblink/expected/dblink.out|  2 +-
 contrib/file_fdw/expected/file_fdw.out|  2 -
 contrib/file_fdw/file_fdw.c   | 23 --
 .../postgres_fdw/expected/postgres_fdw.out|  4 +-
 contrib/postgres_fdw/option.c | 22 +++--
 src/backend/foreign/foreign.c | 25 --
 src/backend/utils/adt/varlena.c   | 82 +++
 src/include/utils/varlena.h   | 12 +++
 src/test/regress/expected/foreign_data.out|  8 +-
 10 files changed, 159 insertions(+), 47 deletions(-)

diff --git a/contrib/dblink/dblink.c b/contrib/dblink/dblink.c
index e323fdd0e6..c134f73adb 100644
--- a/contrib/dblink/dblink.c
+++ b/contrib/dblink/dblink.c
@@ -2008,27 +2008,31 @@ dblink_fdw_validator(PG_FUNCTION_ARGS)
 		{
 			/*
 			 * Unknown option, or invalid option for the context specified, so
-			 * complain about it.  Provide a hint with list of valid options
-			 * for the context.
+			 * complain about it.  Provide a hint with a valid option that
+			 * looks similar, if there is one.
 			 */
-			StringInfoData buf;
 			const PQconninfoOption *opt;
+			const char *closest_match;
+			ClosestMatchState match_state;
+			bool		has_valid_options = false;
 
-			initStringInfo(&buf);
+			initClosestMatch(&match_state, def->defname, 5);
 			for (opt = options; opt->keyword; opt++)
 			{
 if (is_valid_dblink_option(options, opt->keyword, context))
-	appendStringInfo(&buf, "%s%s",
-	 (buf.len > 0) ? ", " : "",
-	 opt->keyword);
+{
+	has_valid_options = true;
+	updateClosestMatch(&match_state, opt->keyword);
+}
 			}
+
+			closest_match = getClosestMatch(&match_state);
 			ereport(ERROR,
 	(errcode(ERRCODE_FDW_OPTION_NAME_NOT_FOUND),
 	 errmsg("invalid option \"%s\"", def->defname),
-	 buf.len > 0
-	 ? errhint("Valid options in this context are: %s",
-			   buf.data)
-	 : errhint("There are no valid options in this context.")));
+	 has_valid_options ? closest_match ?
+	 errhint("Did you mean \"%s\"?", closest_match) : 0 :
+	 errhint("There are no valid options in this context.")));
 		}
 	}
 
diff --git a/contrib/dblink/expected/dblink.out b/contrib/dblink/expected/dblink.out
index c7bde6ad07..2b874fc450 100644
--- a/contrib/dblink/expected/dblink.out
+++ b/contrib/dblink/expected/dblink.out
@@ -897,7 +897,7 @@ $d$;
 CREATE USER MAPPING FOR public SERVER fdtest
   OPTIONS (server 'localhost');  -- fail, can't specify server here
 ERROR:  invalid option "server"
-HINT:  Valid options in this context are: user, password, sslpassword
+HINT:  Did you mean "user"?
 CREATE USER MAPPING FOR public SERVER fdtest OPTIONS (user :'USER');
 GRANT USAGE ON FOREIGN SERVER fdtest TO regress_dblink_user;
 GRANT EXECUTE ON FUNCTION dblink_connect_u(text, text) TO regress_dblink_user;
diff --git a/contrib/file_fdw/expected/file_fdw.out b/contrib/file_fdw/expected/file_fdw.out
index 261af1a8b5..36d76ba26c 100644
--- a/contrib/file_fdw/expected/file_fdw.out
+++ b/contrib/file_fdw/expected/file_fdw.out
@@ -166,7 +166,6 @@ ERROR:  invalid option "force_not_null"
 HINT:  There are no valid options in this context.
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (force_not_null '*'); -- ERROR
 ERROR:  invalid option "force_not_null"
-HINT:  Valid options in this context are: filename, program, format, header, delimiter, quote, escape, null, encoding
 -- force_null is not allowed to be specified at any for

Re: postgres_fdw hint messages

[Nathan Bossart]

On Thu, Sep 01, 2022 at 07:08:49PM -0400, Tom Lane wrote:
> (1) there probably needs to be some threshold of closeness, so we don't
> offer "foobar" when the user wrote "huh"

Agreed.

> (2) there are several places doing this now, and there will no doubt
> be more later, so we need to try to abstract the logic so it can be
> shared.

Will do.

I'm also considering checking whether the user-provided string is longer
than MAX_LEVENSHTEIN_STRLEN so that we can avoid the ERROR from
varstr_levenshtein().  Or perhaps varstr_levenshtein() could indicate that
the string is too long without ERROR-ing (e.g., by returning -1).  If the
user-provided string is too long, we'd just omit the hint.

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com

Re: postgres_fdw hint messages

[Tom Lane]

Nathan Bossart  writes:
> On Fri, Aug 26, 2022 at 12:35:38PM -0400, Tom Lane wrote:
>> I vote for just dropping all these hints for now, while leaving the
>> door open for anyone who wants to write closest-match-offering code.

> Here is a quickly-hacked-together proof-of-concept for using Levenshtein
> distances to determine which option to include in the hint.  Would
> something like this suffice?  If so, I will work on polishing it up a bit.

Seems reasonable to me, but

(1) there probably needs to be some threshold of closeness, so we don't
offer "foobar" when the user wrote "huh"

(2) there are several places doing this now, and there will no doubt
be more later, so we need to try to abstract the logic so it can be
shared.

regards, tom lane

Re: postgres_fdw hint messages

[Nathan Bossart]

On Fri, Aug 26, 2022 at 12:35:38PM -0400, Tom Lane wrote:
> Peter also mentioned the possibility of "did you mean" with a closest
> match offered.  That seems like a reasonable idea if someone
> is motivated to create the code, which I'm not.
> 
> I vote for just dropping all these hints for now, while leaving the
> door open for anyone who wants to write closest-match-offering code.

Here is a quickly-hacked-together proof-of-concept for using Levenshtein
distances to determine which option to include in the hint.  Would
something like this suffice?  If so, I will work on polishing it up a bit.

-- 
Nathan Bossart
Amazon Web Services: https://aws.amazon.com
diff --git a/contrib/dblink/dblink.c b/contrib/dblink/dblink.c
index e323fdd0e6..7fe42cb732 100644
--- a/contrib/dblink/dblink.c
+++ b/contrib/dblink/dblink.c
@@ -2006,28 +2006,31 @@ dblink_fdw_validator(PG_FUNCTION_ARGS)
 
 		if (!is_valid_dblink_option(options, def->defname, context))
 		{
-			/*
-			 * Unknown option, or invalid option for the context specified, so
-			 * complain about it.  Provide a hint with list of valid options
-			 * for the context.
-			 */
-			StringInfoData buf;
-			const PQconninfoOption *opt;
+			int	min_dist = -1;
+			char *hint = NULL;
 
-			initStringInfo(&buf);
-			for (opt = options; opt->keyword; opt++)
+			for (const PQconninfoOption *opt = options; opt->keyword; opt++)
 			{
 if (is_valid_dblink_option(options, opt->keyword, context))
-	appendStringInfo(&buf, "%s%s",
-	 (buf.len > 0) ? ", " : "",
-	 opt->keyword);
+{
+	int dist;
+
+	dist = varstr_levenshtein(def->defname, strlen(def->defname),
+			  opt->keyword, strlen(opt->keyword),
+			  1, 1, 1, false);
+	if (min_dist == -1 || dist < min_dist)
+	{
+		min_dist = dist;
+		hint = opt->keyword;
+	}
+}
 			}
+
 			ereport(ERROR,
 	(errcode(ERRCODE_FDW_OPTION_NAME_NOT_FOUND),
 	 errmsg("invalid option \"%s\"", def->defname),
-	 buf.len > 0
-	 ? errhint("Valid options in this context are: %s",
-			   buf.data)
+	 hint != NULL
+	 ? errhint("Did you mean \"%s\"?", hint)
 	 : errhint("There are no valid options in this context.")));
 		}
 	}
diff --git a/contrib/dblink/expected/dblink.out b/contrib/dblink/expected/dblink.out
index c7bde6ad07..2b874fc450 100644
--- a/contrib/dblink/expected/dblink.out
+++ b/contrib/dblink/expected/dblink.out
@@ -897,7 +897,7 @@ $d$;
 CREATE USER MAPPING FOR public SERVER fdtest
   OPTIONS (server 'localhost');  -- fail, can't specify server here
 ERROR:  invalid option "server"
-HINT:  Valid options in this context are: user, password, sslpassword
+HINT:  Did you mean "user"?
 CREATE USER MAPPING FOR public SERVER fdtest OPTIONS (user :'USER');
 GRANT USAGE ON FOREIGN SERVER fdtest TO regress_dblink_user;
 GRANT EXECUTE ON FUNCTION dblink_connect_u(text, text) TO regress_dblink_user;
diff --git a/contrib/file_fdw/expected/file_fdw.out b/contrib/file_fdw/expected/file_fdw.out
index 261af1a8b5..b780b1a13c 100644
--- a/contrib/file_fdw/expected/file_fdw.out
+++ b/contrib/file_fdw/expected/file_fdw.out
@@ -166,7 +166,7 @@ ERROR:  invalid option "force_not_null"
 HINT:  There are no valid options in this context.
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (force_not_null '*'); -- ERROR
 ERROR:  invalid option "force_not_null"
-HINT:  Valid options in this context are: filename, program, format, header, delimiter, quote, escape, null, encoding
+HINT:  Did you mean "format"?
 -- force_null is not allowed to be specified at any foreign object level:
 ALTER FOREIGN DATA WRAPPER file_fdw OPTIONS (ADD force_null '*'); -- ERROR
 ERROR:  invalid option "force_null"
@@ -179,7 +179,7 @@ ERROR:  invalid option "force_null"
 HINT:  There are no valid options in this context.
 CREATE FOREIGN TABLE tbl () SERVER file_server OPTIONS (force_null '*'); -- ERROR
 ERROR:  invalid option "force_null"
-HINT:  Valid options in this context are: filename, program, format, header, delimiter, quote, escape, null, encoding
+HINT:  Did you mean "null"?
 -- basic query tests
 SELECT * FROM agg_text WHERE b > 10.0 ORDER BY a;
   a  |   b
diff --git a/contrib/file_fdw/file_fdw.c b/contrib/file_fdw/file_fdw.c
index 4773cadec0..49dec5b7bf 100644
--- a/contrib/file_fdw/file_fdw.c
+++ b/contrib/file_fdw/file_fdw.c
@@ -37,6 +37,7 @@
 #include "utils/memutils.h"
 #include "utils/rel.h"
 #include "utils/sampling.h"
+#include "utils/varlena.h"
 
 PG_MODULE_MAGIC;
 
@@ -213,27 +214,31 @@ file_fdw_validator(PG_FUNCTION_ARGS)
 
 		if (!is_valid_option(def->defname, catalog))
 		{
-			const struct FileFdwOption *opt;
-			StringInfoData buf;
+			int min_dist = -1;
+			const char *hint = NULL;
 
-			/*
-			 * Unknown option specified, complain about it. Provide a hint
-			 * with list of valid options for the object.
-			 */
-			initStringInfo(&buf);
-			for (opt = valid_options; opt->optname; opt++)
+			for (const struct FileFdwOption *opt = valid_options; opt->

Re: postgres_fdw hint messages

[Peter Eisentraut]

On 25.08.22 15:42, Peter Eisentraut wrote:
It's also questionable how useful this hint is in its current form, 
considering how long it is and that the options are in an 
implementation-dependent order.


Possible changes:



- Remove all the hints like this from foreign data commands.


It appears that there was a strong preference toward this solution, so 
that's what I implemented in the updated patch set.


(Considering the hints that are removed in the tests cases, I don't 
think this loses any value.  What might be useful in practice instead is 
something like "the option you specified on this foreign server should 
actually be specified on a user mapping or foreign table", but this 
would take a fair amount of code to cover a reasonable set of cases, so 
I'll leave this as a future exercise.)From c079cf33ad8033875a6e18b9cff06e47330007ac Mon Sep 17 00:00:00 2001
From: Peter Eisentraut 
Date: Thu, 25 Aug 2022 15:31:10 +0200
Subject: [PATCH v2 1/2] postgres_fdw: Remove useless DO block in test

---
 contrib/postgres_fdw/expected/postgres_fdw.out | 8 +---
 contrib/postgres_fdw/sql/postgres_fdw.sql  | 6 +-
 2 files changed, 2 insertions(+), 12 deletions(-)

diff --git a/contrib/postgres_fdw/expected/postgres_fdw.out 
b/contrib/postgres_fdw/expected/postgres_fdw.out
index 7bf35602b0..a42c9720c3 100644
--- a/contrib/postgres_fdw/expected/postgres_fdw.out
+++ b/contrib/postgres_fdw/expected/postgres_fdw.out
@@ -9621,15 +9621,9 @@ ERROR:  password is required
 DETAIL:  Non-superusers must provide a password in the user mapping.
 -- If we add a password to the connstr it'll fail, because we don't allow 
passwords
 -- in connstrs only in user mappings.
-DO $d$
-BEGIN
-EXECUTE $$ALTER SERVER loopback_nopw OPTIONS (ADD password 
'dummypw')$$;
-END;
-$d$;
+ALTER SERVER loopback_nopw OPTIONS (ADD password 'dummypw');
 ERROR:  invalid option "password"
 HINT:  Valid options in this context are: service, passfile, channel_binding, 
connect_timeout, dbname, host, hostaddr, port, options, application_name, 
keepalives, keepalives_idle, keepalives_interval, keepalives_count, 
tcp_user_timeout, sslmode, sslcompression, sslcert, sslkey, sslrootcert, 
sslcrl, sslcrldir, sslsni, requirepeer, ssl_min_protocol_version, 
ssl_max_protocol_version, gssencmode, krbsrvname, gsslib, target_session_attrs, 
use_remote_estimate, fdw_startup_cost, fdw_tuple_cost, extensions, updatable, 
truncatable, fetch_size, batch_size, async_capable, parallel_commit, 
keep_connections
-CONTEXT:  SQL statement "ALTER SERVER loopback_nopw OPTIONS (ADD password 
'dummypw')"
-PL/pgSQL function inline_code_block line 3 at EXECUTE
 -- If we add a password for our user mapping instead, we should get a different
 -- error because the password wasn't actually *used* when we run with trust 
auth.
 --
diff --git a/contrib/postgres_fdw/sql/postgres_fdw.sql 
b/contrib/postgres_fdw/sql/postgres_fdw.sql
index 42735ae78a..63581a457d 100644
--- a/contrib/postgres_fdw/sql/postgres_fdw.sql
+++ b/contrib/postgres_fdw/sql/postgres_fdw.sql
@@ -2886,11 +2886,7 @@ CREATE FOREIGN TABLE pg_temp.ft1_nopw (
 -- If we add a password to the connstr it'll fail, because we don't allow 
passwords
 -- in connstrs only in user mappings.
 
-DO $d$
-BEGIN
-EXECUTE $$ALTER SERVER loopback_nopw OPTIONS (ADD password 
'dummypw')$$;
-END;
-$d$;
+ALTER SERVER loopback_nopw OPTIONS (ADD password 'dummypw');
 
 -- If we add a password for our user mapping instead, we should get a different
 -- error because the password wasn't actually *used* when we run with trust 
auth.
-- 
2.37.1

From eef24034a75e674e7e4a929557906395eab7673f Mon Sep 17 00:00:00 2001
From: Peter Eisentraut 
Date: Tue, 30 Aug 2022 09:08:53 +0200
Subject: [PATCH v2 2/2] Remove hints from FDW's invalid option errors

The FDWs provided in tree all had code to list valid options in an
error message hint if an invalid option was given to a
forein-data-related command.  These lists have in some cases gotten
extremely bulky, and in general they don't really help the user
correct their command.  (They might help in case of typos, but not if
there is a semantic misunderstanding about how the foreign-data setup
should be configured.)  So per discussion, remove these hints.

Discussion: 
https://www.postgresql.org/message-id/flat/b1f9f399-3a1a-b554-283f-4ae7f34608e2%40enterprisedb.com
---
 contrib/dblink/dblink.c   | 24 +--
 contrib/dblink/expected/dblink.out|  2 --
 contrib/file_fdw/expected/file_fdw.out|  8 ---
 contrib/file_fdw/file_fdw.c   | 23 +-
 .../postgres_fdw/expected/postgres_fdw.out|  3 ---
 contrib/postgres_fdw/option.c | 23 +-
 src/backend/foreign/foreign.c | 19 +--
 src/test/regress/expected/foreign_data.out|  5 
 8 files changed, 4 insertions(+), 103 deletions(-)

diff --git a/contrib/dblink/dblink.c b/contrib/d

Re: postgres_fdw hint messages

[Tom Lane]

Robert Haas  writes:
> On Thu, Aug 25, 2022 at 9:42 AM Peter Eisentraut
>  wrote:
>> HINT:  Valid options in this context are: service, passfile,
>> channel_binding, connect_timeout, dbname, host, hostaddr, port, options,
>> application_name, keepalives, keepalives_idle, keepalives_interval,
>> keepalives_count, tcp_user_timeout, sslmode, sslcompression, sslcert,
>> sslkey, sslrootcert, sslcrl, sslcrldir, sslsni, requirepeer,
>> ssl_min_protocol_version, ssl_max_protocol_version, gssencmode,
>> krbsrvname, gsslib, target_session_attrs, use_remote_estimate,
>> fdw_startup_cost, fdw_tuple_cost, extensions, updatable, truncatable,
>> fetch_size, batch_size, async_capable, parallel_commit, keep_connections
>> 
>> This annoys developers who are working on libpq connection options,
>> because any option added, removed, or changed causes this test to need
>> to be updated.
>> 
>> It's also questionable how useful this hint is in its current form,
>> considering how long it is and that the options are in an
>> implementation-dependent order.

> I think the place to list the legal options is in the documentation,
> not the HINT.

I think listing them in a hint is reasonable as long as the hint doesn't
get longer than a line or two.  This one is entirely out of hand, so
I agree with just dropping it.

Note that there is essentially identical code in dblink, file_fdw,
and backend/foreign/foreign.c.  Do we want to nuke them all?  Or
maybe make a policy decision to suppress such HINTs when there are
more than ~10 matches?  (The latter policy would likely eventually
end by always suppressing everything...)

Peter also mentioned the possibility of "did you mean" with a closest
match offered.  That seems like a reasonable idea if someone
is motivated to create the code, which I'm not.

I vote for just dropping all these hints for now, while leaving the
door open for anyone who wants to write closest-match-offering code.

regards, tom lane

Re: postgres_fdw hint messages

[Robert Haas]

On Thu, Aug 25, 2022 at 9:42 AM Peter Eisentraut
 wrote:
> The postgres_fdw tests contain this (as amended by patch 0001):
>
> ALTER SERVER loopback_nopw OPTIONS (ADD password 'dummypw');
> ERROR:  invalid option "password"
> HINT:  Valid options in this context are: service, passfile,
> channel_binding, connect_timeout, dbname, host, hostaddr, port, options,
> application_name, keepalives, keepalives_idle, keepalives_interval,
> keepalives_count, tcp_user_timeout, sslmode, sslcompression, sslcert,
> sslkey, sslrootcert, sslcrl, sslcrldir, sslsni, requirepeer,
> ssl_min_protocol_version, ssl_max_protocol_version, gssencmode,
> krbsrvname, gsslib, target_session_attrs, use_remote_estimate,
> fdw_startup_cost, fdw_tuple_cost, extensions, updatable, truncatable,
> fetch_size, batch_size, async_capable, parallel_commit, keep_connections
>
> This annoys developers who are working on libpq connection options,
> because any option added, removed, or changed causes this test to need
> to be updated.
>
> It's also questionable how useful this hint is in its current form,
> considering how long it is and that the options are in an
> implementation-dependent order.

I think the place to list the legal options is in the documentation,
not the HINT.

-- 
Robert Haas
EDB: http://www.enterprisedb.com

Re: postgres_fdw hint messages

[Ibrar Ahmed]

On Thu, Aug 25, 2022 at 6:42 PM Peter Eisentraut <
peter.eisentr...@enterprisedb.com> wrote:

> The postgres_fdw tests contain this (as amended by patch 0001):
>
> ALTER SERVER loopback_nopw OPTIONS (ADD password 'dummypw');
> ERROR:  invalid option "password"
> HINT:  Valid options in this context are: service, passfile,
> channel_binding, connect_timeout, dbname, host, hostaddr, port, options,
> application_name, keepalives, keepalives_idle, keepalives_interval,
> keepalives_count, tcp_user_timeout, sslmode, sslcompression, sslcert,
> sslkey, sslrootcert, sslcrl, sslcrldir, sslsni, requirepeer,
> ssl_min_protocol_version, ssl_max_protocol_version, gssencmode,
> krbsrvname, gsslib, target_session_attrs, use_remote_estimate,
> fdw_startup_cost, fdw_tuple_cost, extensions, updatable, truncatable,
> fetch_size, batch_size, async_capable, parallel_commit, keep_connections
>
> This annoys developers who are working on libpq connection options,
> because any option added, removed, or changed causes this test to need
> to be updated.
>
> It's also questionable how useful this hint is in its current form,
> considering how long it is and that the options are in an
> implementation-dependent order.
>
>
Thanks Peter, for looking at that; this HINT message is growing over time.

In my opinion, we should hide the complete message in case of an invalid
option. But
try to show dependent options; for example, if someone specify "sslcrl" and
that option
require some more options, then show the HINT of that options.

Possible changes:
>
> - Hide the hint from this particular test (done in the attached patches).
>
>

> - Keep the hint, but maybe make it sorted?
>
> - Remove all the hints like this from foreign data commands.
>
> - Don't show the hint when there are more than N valid options.
>
> - Do some kind of "did you mean" like we have for column names.
>
> Thoughts?



-- 
Ibrar Ahmed

Re: postgres_fdw hint messages

[Ranier Vilela]

Em qui., 25 de ago. de 2022 às 14:31, Ranier Vilela 
escreveu:

> >The postgres_fdw tests contain this (as amended by patch 0001):
>
> >ALTER SERVER loopback_nopw OPTIONS (ADD password 'dummypw');
> >ERROR: invalid option "password"
> >HINT: Valid options in this context are: service, passfile,
> >channel_binding, connect_timeout, dbname, host, hostaddr, port, options,
> >application_name, keepalives, keepalives_idle, keepalives_interval,
> >keepalives_count, tcp_user_timeout, sslmode, sslcompression, sslcert,
> >sslkey, sslrootcert, sslcrl, sslcrldir, sslsni, requirepeer,
> >ssl_min_protocol_version, ssl_max_protocol_version, gssencmode,
> >krbsrvname, gsslib, target_session_attrs, use_remote_estimate,
> >fdw_startup_cost, fdw_tuple_cost, extensions, updatable, truncatable,
> >fetch_size, batch_size, async_capable, parallel_commit, keep_connections
>
> >This annoys developers who are working on libpq connection options,
> >because any option added, removed, or changed causes this test to need
> >to be updated.
>
> >It's also questionable how useful this hint is in its current form,
> >considering how long it is and that the options are in an
> >implementation-dependent order.
>
> >Possible changes:
>
> >- Hide the hint from this particular test (done in the attached patches).
> +1
> I vote for this option.
> Less work for future developers changes, I think worth the effort.
>
> Anyway, in alphabetical order, it's a lot easier for users to read.
>
> Patch attached.
>
Little tweak in the comments.

regards,
Ranier Vilela

>
>


v1-0003-reorder-alphabetical-libpq-options.patch
Description: Binary data

re: postgres_fdw hint messages

[Ranier Vilela]

>The postgres_fdw tests contain this (as amended by patch 0001):

>ALTER SERVER loopback_nopw OPTIONS (ADD password 'dummypw');
>ERROR: invalid option "password"
>HINT: Valid options in this context are: service, passfile,
>channel_binding, connect_timeout, dbname, host, hostaddr, port, options,
>application_name, keepalives, keepalives_idle, keepalives_interval,
>keepalives_count, tcp_user_timeout, sslmode, sslcompression, sslcert,
>sslkey, sslrootcert, sslcrl, sslcrldir, sslsni, requirepeer,
>ssl_min_protocol_version, ssl_max_protocol_version, gssencmode,
>krbsrvname, gsslib, target_session_attrs, use_remote_estimate,
>fdw_startup_cost, fdw_tuple_cost, extensions, updatable, truncatable,
>fetch_size, batch_size, async_capable, parallel_commit, keep_connections

>This annoys developers who are working on libpq connection options,
>because any option added, removed, or changed causes this test to need
>to be updated.

>It's also questionable how useful this hint is in its current form,
>considering how long it is and that the options are in an
>implementation-dependent order.

>Possible changes:

>- Hide the hint from this particular test (done in the attached patches).
+1
I vote for this option.
Less work for future developers changes, I think worth the effort.

Anyway, in alphabetical order, it's a lot easier for users to read.

Patch attached.

regards,
Ranier Vilela


0003-reorder-alphabetical-libpq-options.patch
Description: Binary data