PHOENIX-7873: Incorporate HBASE-29974 filter seek hints (compat-2.6.6 module) [5.3]

[shubham-roy]

What changes were proposed in this pull request?

Backport of PHOENIX-7873 to the 5.3 branch. Incorporates the new HBase filter seek-hint methods — getSkipHint / getHintForRejectedRow, added to
Filter by HBASE-29974 and propagated through composite filters by
HBASE-30150 — into Phoenix's wrapper filters, so a wrapped delegate's seek hint is no longer
swallowed.

Identical to the master PR except for the new module pom's parent version (5.3.2-SNAPSHOT). Because these Filter methods exist only in HBase 2.6.6+,
this follows the PHOENIX-7731 precedent (commit 0d71499104) and adds a new version-gated compat module phoenix-hbase-compat-2.6.6 (a copy of
phoenix-hbase-compat-2.6.4) where the gated @Overrides live. Older compat modules are untouched.

• New module phoenix-hbase-compat-2.6.6 — verbatim copy of 2.6.4, plus the two seek-hint forwarding overrides:
  • CompatDelegateFilter — unconditional forwarding to the delegate.
  • CompatPagingFilter — null-guarded forwarding (falls back to super when there is no delegate).
• DelegateFilter re-parented from FilterBase to CompatDelegateFilter, so it and its subclasses (AllVersionsIndexRebuildFilter,
  UnverifiedRowFilter) inherit the forwarding. PagingFilter already extends CompatPagingFilter (unchanged).
• Build wiring (root pom.xml): new module in <modules>; hbase-2.6.5.runtime.version split out; the 2.6 family profile repointed to the 2.6.6
  module; a new pinned hbase.profile=2.6.5 profile for the displaced 2.6.5 line; 5 dependencyManagement entries; enforcer beanshell clause; assembly
  coverage dependency.

Class hierarchy after this change:

FilterBase (HBase)
  └─ CompatDelegateFilter   (phoenix-hbase-compat-2.6.6: forwards getSkipHint/getHintForRejectedRow)
       └─ DelegateFilter    (phoenix-core-client)
            ├─ AllVersionsIndexRebuildFilter
            └─ UnverifiedRowFilter

FilterBase (HBase)
  └─ CompatPagingFilter     (phoenix-hbase-compat-2.6.6: null-guarded forwarding)
       └─ PagingFilter       (phoenix-core-client)

⚠️ Draft — blocked on HBase 2.6.6 GA. HBase 2.6.6 is not yet GA on Maven Central (the JIRAs are merged and present in tag 2.6.6RC0, but no
2.6.6-hadoop3 artifact is published). This branch pins 2.6.6-SNAPSHOT, which only resolves against a locally-installed HBase build. Two
2.6.6-SNAPSHOT markers (root pom.xml <hbase-2.6.runtime.version> and phoenix-hbase-compat-2.6.6/pom.xml <hbase26.compat.version>, both carrying
TODO(PHOENIX-7873) comments) must flip to 2.6.6-hadoop3 at GA before merge.

Why are the changes needed?

HBASE-29974 lets a Filter return a seek hint when it skips/rejects a row so the scanner can jump ahead instead of scanning cell-by-cell, and HBASE-30150
makes composite filters propagate that hint. Phoenix's wrapper filters (DelegateFilter, PagingFilter) extend FilterBase, whose default
implementations of these methods return no hint. As a result, when one of these wrappers wraps a delegate that does produce a seek hint, the hint is
swallowed and the scan loses the skip optimization. Forwarding the hint from the delegate restores that optimization for wrapped filters on HBase 2.6.6+.

Does this PR introduce any user-facing change?

No functional/result change. This is a scan-performance behavior change that only takes effect on HBase 2.6.6+: wrapped delegate filters can now
contribute seek hints instead of having them swallowed. Query results are unchanged; only how efficiently the scanner skips rows/cells differs. Against
all currently released Phoenix/HBase versions there is no observable change, since the methods do not exist before HBase 2.6.6.

How was this patch tested?

Verified locally (JDK 8) against a locally-installed HBase 2.6.6-SNAPSHOT, on the 5.3 branch:

• -Dhbase.profile=2.6 build — phoenix-hbase-compat-2.6.6 + phoenix-core-client + phoenix-core compile; new forwarding unit tests pass
  (CompatDelegateFilterTest, CompatPagingFilterTest) plus the structural test.
• Default profile (HBase 2.5.x) build — no regression; the profile-safe structural test (DelegateFilterStructureTest, instanceof-only) compiles
  and passes where the new Filter methods are absent, proving the version gating.
• Pinned -Dhbase.profile=2.6.5 build — the displaced 2.6.4 module still compiles against 2.6.5-hadoop3; enforcer passes.
• Spotless clean on all changed files.

Was this patch authored or co-authored using generative AI tooling?

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