Mark database semconv as release candidate

[trask]

Fixes #964
Fixes #965

Changes

Mark database semconv as release candidate

Using the notes/briefs to mark attributes/enum values as "release candidate" pending #1096

[trask]

need to define db.namespace

[trask]

need to define db.namespace

[trask]

need to define db.namespace

[trask]

from https://www.postgresql.org/docs/current/manage-ag-overview.html:

the full hierarchy is: cluster, database, schema, table (or some other kind of object, such as a function).

[trask]

Cluster name

From https://www.postgresql.org/docs/16/runtime-config-logging.html#RUNTIME-CONFIG-LOGGING-PROC-TITLE

name that identifies this database cluster (instance) for various purposes. The cluster name appears in the process title for all server processes in this cluster.

I don't believe the cluster name is used when connecting to a database, and so unlikely to be available to instrumentation.

I'd suggest we leave this out for now, can always add it as optional prefix in the future if we find use case and better understanding of it.

[trask]

In postgres, client has searchpath which is one or more "current" schemas

https://www.postgresql.org/docs/current/ddl-schemas.html/l

The first schema named in the search path is called the current schema

db.namespace could be defined as database.currentschema

Example 1

• db.namespace = mydatabase.myschema
• db.query.text = select * from mytable
• db.collection.name = mytable

Example 2

• db.namespace = mydatabase.myschema
• db.query.text = select * from myschema.mytable
• db.collection.name = myschema.mytable

Example 3

• db.namespace = mydatabase.myschema
• db.query.text = select * from myschema2.mytable
• db.collection.name = myschema2.mytable

Example 1 (db namespace doesn't know schema):

• db.namespace = mydatabase
• db.query.text = select * from mytable
• db.collection.name = mytable

Example 2 (db namespace doesn't know schema):

• db.namespace = mydatabase
• db.query.text = select * from myschema.mytable
• db.collection.name = myschema.mytable

Example 3 (db namespace doesn't know schema):

• db.namespace = mydatabase
• db.query.text = select * from myschema2.mytable
• db.collection.name = myschema2.mytable

[trask]

In https://github.com/open-telemetry/semantic-conventions/blob/main/docs/database/sql.md:

If instrumentation cannot reliably determine the current database name, it SHOULD NOT set db.namespace.

Consider relaxing this to "best effort".

If a database system has multiple namespace components

Consider mentioning schema as an example component.