Only query aurora_version() if aurora postgres extensions are available

[eric-weaver]

What does this PR do?

Currently the Postgres integration always calls aurora_version() to check if the database is running on AWS Aurora. If it's not, the query fails with a function not found error. This leads to query errors in database logs. To avoid calling a function that won't exist outside of AWS Aurora environment, we will now lookup available postgres extensions. If aurora related extensions are available, we can assume we're running in AWS and will verify by querying the aurora_version(). Changes were made to the VersionUtils.is_aurora() to cache the results of the first execution as this shouldn't change over the lifetime of the connection.

Running this query on Aurora Postgres will return the following extensions

SELECT * FROM pg_available_extension_versions WHERE name ILIKE '%aurora%' OR comment ILIKE '%aurora%';
       name        | version | installed | superuser | relocatable |    schema     | requires |                              comment                              
-------------------+---------+-----------+-----------+-------------+---------------+----------+-------------------------------------------------------------------
 rds_tools         | 1.0     | f         | t         | f           | rds_tools     |          | miscellaneous administrative functions for Aurora PostgreSQL
 aurora_stat_utils | 1.0     | f         | t         | f           |               |          | Statistics utility functions
 apg_plan_mgmt     | 2.1     | f         | t         | f           | apg_plan_mgmt |          | Amazon Aurora with PostgreSQL compatibility Query Plan Management
 apg_plan_mgmt     | 1.0.1   | f         | t         | f           | apg_plan_mgmt |          | Amazon Aurora with PostgreSQL compatibility Query Plan Management
 apg_plan_mgmt     | 1.0     | f         | t         | f           | apg_plan_mgmt |          | Amazon Aurora with PostgreSQL compatibility Query Plan Management
 apg_plan_mgmt     | 2.0     | f         | t         | f           | apg_plan_mgmt |          | Amazon Aurora with PostgreSQL compatibility Query Plan Management

Running it on non Aurora Postgres instances will return zero rows.

Motivation

Review checklist (to be filled by reviewers)

• Feature or bugfix MUST have appropriate tests (unit, integration, e2e)
• Add the qa/skip-qa label if the PR doesn't need to be tested during QA.
• If you need to backport this PR to another branch, you can add the backport/<branch-name> label to the PR and it will automatically open a backport PR once this one is merged

[nenadnoveljic]

How to speed up the test (minor nitpick):

• Use LIMIT 1 to stop scanning after the first row — enough to confirm it’s Aurora.
• Use fetchone instead of fetchall.
• Replace SELECT * with SELECT 1.

Not a blocker - approving the PR.

[eric-weaver]

Good call! Needed to fix linting errors on this anyway, so applied the suggested improvements and validated its working correctly on and off Aurora

Review from nenadnoveljic is dismissed. Related teams and files:

• database-monitoring-agent
  • postgres/datadog_checks/postgres/version_utils.py

Review from lu-zhengda is dismissed. Related teams and files:

• database-monitoring-agent
  • postgres/datadog_checks/postgres/version_utils.py

[codecov]

Codecov Report

Attention: Patch coverage is 30.76923% with 9 lines in your changes missing coverage. Please review.

Project coverage is 90.33%. Comparing base (40e4f36) to head (e37ec05).
Report is 4 commits behind head on master.

Additional details and impacted files

Flag	Coverage Δ
activemq	?
cassandra	?
confluent_platform	?
hive	?
hivemq	?
hudi	?
ignite	?
jboss_wildfly	?
kafka	?
postgres	93.18% <30.76%> (+3.50%)	⬆️
presto	?
solr	?
tomcat	?
weblogic	?

Flags with carried forward coverage won't be shown. Click here to find out more.

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.