Codec preference is not considered leading to OID value decoding through `DayOfWeek`

[turneand]

Versions

• Driver: r2dbc-postgresql#1.1.0.RELEASE0
• Database: v17
• Java: 21
• OS: Windows + Linux

Current Behavior

We have some monitoring queries against the pg_stat_activity table and since upgrading to 1.1.0.RELEASE we're now erroring out with the message:

Invalid value for DayOfWeek: 16478

This occurs when reading the values for the "datid" and "usesysid" fields, which are both of the "oid" type

Table schema

n/a - the pg_stat_activity is a built-in table

SELECT * FROM pg_stat_activity

Steps to reproduce

Small snippet of code to read all of the columns from this table based on an existing ConnectionFactory

private static void execute(ConnectionFactory factory) {
  try {
    var result = Mono.usingWhen(Mono.fromDirect(factory.create()),
                                 con -> Mono.fromDirect(con.createStatement("SELECT * FROM pg_stat_activity LIMIT 10").execute())
                               .flatMapMany(rs -> rs.map((row, meta) -> {
                                      return meta.getColumnMetadatas().stream().map(x -> {
                                           try {
                                             var value = row.get(x.getName());
											 return value != null ? x.getName() + "=" + value : null;
										   } catch (Exception e) {
										     return x.getName() + "=" + e.getMessage();
										   }
									  }).filter(Objects::nonNull).toList();
									}))
									.collectList(), Connection::close, (con, t) -> con.close(), Connection::close)
									.block(Duration.ofSeconds(10));
	log.info("success - {}", result);
  } catch (Exception e) {
    log.error("error", e);
  }
}

Expected behavior/code

An oid should not be treated as a DayOfWeek
I can workaround for the moment by explicitly casting the two columns into a "text" type, but this should not be necessary.

Possible Solution

n/a

Additional context

Looks like this was a new capability added under #591

[mp911de]

Thanks for reaching out. Upon investigation, there are many other cases that fail from improper codec preference. The issue comes from relying on canDecode outcome as preference indicator. While many codecs can (and should) decode values from various Postgres types (OID, INT4, …), that doesn't necessary mean they should be preferred when decoding values to Object (Number and Temporal).

[mp911de]

There's now a new 1.1.1.BUILD-SNAPSHOT version available from Central snapshots. Care to verify whether the fix solves the problem on your side?

<repository>
  <id>central-portal-snapshots</id>
  <name>Central Portal Snapshots</name>
  <url>https://central.sonatype.com/repository/maven-snapshots/</url>
</repository>