[GEOT-7230] Implement a HINT parameter as part of the HANA plug-in

[stefanuhrig]

This pull request adds a new "SELECT Hint" parameter to the HANA JDBC plugin.

SELECT Hints are appended to SELECT queries, embedded in the string

        WITH HINT( <SELECT Hints> )

Setting SELECT Hints enables a user to configure HANA specific query hints that will be considered during query plan generation.

Checklist

• I have read the contribution guidelines.
• I have sent a Contribution Licence Agreement (not required for small changes, e.g., fixing typos in documentation).
• First PR targets the main branch (backports managed later; ignore for branch specific issues).
• Avoid Java 9+ split packages.
• All the build checks are green (see automated QA checks).

For core and extension modules:

• New unit tests have been added covering the changes.
• Documentation has been updated (if change is visible to end users).
• There is an issue in GeoTools Jira (except for changes not visible to end users).
• Commit message(s) must be in the form [GEOT-XYZW] Title of the Jira ticket.
• Bug fixes and small new features are presented as a single commit.
• The commit targets a single objective (if multiple focuses cannot be avoided, each one is in its own commit, and has a separate ticket describing it).

[florsc]

In the documentation it says the fifth parameter is for example input. Should be put ESTIMATION_SAMPLES(0) and NO_HASH_JOIN in there?

[stefanuhrig]

I initially did this, but then realized that the GeoServer connection dialog uses the sample to pre-populate the textbox. Hence, I reverted it to null.

[florsc]

Is there an M missing in ESTIMATION_SAPLES(0)?

[stefanuhrig]

Yes, fixed it.

[geoserver-bot]

The backport to 28.x failed:

The process '/usr/bin/git' failed with exit code 128

stderr

error: commit 02e8192e63c9b71e8fd4ca013429d8ffe4c4474c is a merge but no -m option was given.
fatal: cherry-pick failed

stdout

Auto-merging modules/plugin/jdbc/jdbc-hana/src/main/java/org/geotools/data/hana/HanaDialect.java
[backport-4064-to-28.x e1bb602eaf] [GEOT-7230] Implement a HINT parameter as part of the HANA plug-in
 Author: Stefan Uhrig <stefan.uhrig@sap.com>
 Date: Thu Oct 13 17:29:43 2022 +0200
 5 files changed, 149 insertions(+), 32 deletions(-)
 create mode 100644 modules/plugin/jdbc/jdbc-hana/src/test/java/org/geotools/data/hana/HanaSelectHintOnlineTest.java

To backport manually, run these commands in your terminal:

# Fetch latest updates from GitHub
git fetch
# Create a new working tree
git worktree add .worktrees/backport-28.x 28.x
# Navigate to the new working tree
cd .worktrees/backport-28.x
# Create a new branch
git switch --create backport-4064-to-28.x
# Cherry-pick the merged commit of this pull request and resolve the conflicts
git cherry-pick 0f98e73346b98a67dd2e0acf596b79982eae7471,02e8192e63c9b71e8fd4ca013429d8ffe4c4474c,ffc51f5c06535fef254993138cf336975774d308
# Push it to GitHub
git push --set-upstream origin backport-4064-to-28.x
# Go back to the original working tree
cd ../..
# Delete the working tree
git worktree remove .worktrees/backport-28.x

Then, create a pull request where the base branch is 28.x and the compare/head branch is backport-4064-to-28.x.