v50-0011-comparison-point-wording.patch

From 5bd608289c6fb912c1327df7280c8e06024a7c9d Mon Sep 17 00:00:00 2001
From: Henson Choi <assam258@gmail.com>
Date: Fri, 19 Jun 2026 13:04:00 +0900
Subject: [PATCH v50 20/29] Rename absorption "judgment point" to "comparison
 point" in comments

The absorption analysis comments described the ABSORBABLE element flag
as a "judgment point".  Use "comparison point" instead, which says more
directly what happens there: where consecutive iterations are compared.
This touches comments and the executor README only, across the planner,
executor, and EXPLAIN deparse, plus the rpr_base test comments; the
"equivalence judgment" wording and all identifiers are unchanged.

No change to behavior or to query output.
---
 src/backend/commands/explain.c         |  2 +-
 src/backend/executor/README.rpr        |  4 ++--
 src/backend/executor/execRPR.c         | 29 +++++++++++++-------------
 src/backend/optimizer/plan/rpr.c       | 14 ++++++-------
 src/include/optimizer/rpr.h            |  2 +-
 src/test/regress/expected/rpr_base.out |  6 +++---
 src/test/regress/sql/rpr_base.sql      |  6 +++---
 7 files changed, 32 insertions(+), 31 deletions(-)

diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c
index 423cf352125..b3fc324718d 100644
--- a/src/backend/commands/explain.c
+++ b/src/backend/commands/explain.c
@@ -2937,7 +2937,7 @@ append_rpr_quantifier(StringInfo buf, RPRPatternElement *elem)
 		appendStringInfoChar(buf, '?');
 	}
 
-	/* Append absorption markers: " for judgment point, ' for branch only */
+	/* Append absorption markers: " for comparison point, ' for branch only */
 	if (RPRElemIsAbsorbable(elem))
 	{
 		Assert(elem->max == RPR_QUANTITY_INF);
diff --git a/src/backend/executor/README.rpr b/src/backend/executor/README.rpr
index 713ad84e1d9..50d1ff87f7e 100644
--- a/src/backend/executor/README.rpr
+++ b/src/backend/executor/README.rpr
@@ -285,7 +285,7 @@ Element flags (1 byte, bitmask):
         absorption.
 
   0x08  RPR_ELEM_ABSORBABLE         (VAR, END)
-        Absorption judgment point.  Where to compare consecutive
+        Absorption comparison point.  Where to compare consecutive
         iterations for absorption.
           - Simple unbounded VAR (A+): set on the VAR itself
           - Unbounded GROUP ((A B)+): set on the END element only
@@ -1393,7 +1393,7 @@ XII-5. Execution Optimization Summary
     counts) combination through multiple paths. Additionally, for
     group absorption, nfa_match performs inline advance from bounded
     VARs (count >= max) within the absorbable region (ABSORBABLE_BRANCH)
-    through END chains to reach the judgment point (ABSORBABLE END).
+    through END chains to reach the comparison point (ABSORBABLE END).
     This process can also produce duplicate states reaching the same END.
     nfa_add_state_unique() blocks duplicate addition of identical states
     in both cases.
diff --git a/src/backend/executor/execRPR.c b/src/backend/executor/execRPR.c
index 099b81aeb81..90e3a068f04 100644
--- a/src/backend/executor/execRPR.c
+++ b/src/backend/executor/execRPR.c
@@ -578,7 +578,7 @@ nfa_update_absorption_flags(RPRNFAContext *ctx)
 	/*
 	 * Iterate through all states to check absorption status. Uses
 	 * state->isAbsorbable which tracks if state is in absorbable region. This
-	 * is different from RPRElemIsAbsorbable(elem) which checks judgment
+	 * is different from RPRElemIsAbsorbable(elem) which checks comparison
 	 * point.
 	 */
 	for (state = ctx->states; state != NULL; state = state->next)
@@ -625,8 +625,8 @@ nfa_states_covered(RPRPattern *pattern, RPRNFAContext *older, RPRNFAContext *new
 		depth = elem->depth;
 
 		/*
-		 * Only compare at absorption judgment points (RPR_ELEM_ABSORBABLE).
-		 * Judgment points are where count-dominance guarantees the newer
+		 * Only compare at absorption comparison points (RPR_ELEM_ABSORBABLE).
+		 * Comparison points are where count-dominance guarantees the newer
 		 * context's future matches are a subset of the older's.
 		 */
 		if (!RPRElemIsAbsorbable(elem))
@@ -782,7 +782,8 @@ nfa_eval_var_match(WindowAggState *winstate, RPRPatternElement *elem,
  *     previous advance when count >= min was satisfied)
  *
  * For VARs that reached max count followed by END:
- *   - Advance through the END-element chain to the absorption judgment point
+ *   - Advance through the END-element chain to the absorption
+ *     comparison point
  *   - Only deterministic exits (count >= max, max != INF) are handled
  *   - Chains through END elements while count >= max (must-exit path)
  *
@@ -800,7 +801,7 @@ nfa_match(WindowAggState *winstate, RPRNFAContext *ctx, bool *varMatched)
 	/*
 	 * Evaluate VAR elements against current row. For VARs that reach max
 	 * count with END next, advance through the chain of END elements inline
-	 * so absorb phase can compare states at judgment points.
+	 * so absorb phase can compare states at comparison points.
 	 */
 	for (state = ctx->states; state != NULL; state = nextState)
 	{
@@ -831,7 +832,7 @@ nfa_match(WindowAggState *winstate, RPRNFAContext *ctx, bool *varMatched)
 
 				/*
 				 * For VAR at max count with END next, advance through END
-				 * chain to reach the absorption judgment point.  Only
+				 * chain to reach the absorption comparison point.  Only
 				 * deterministic exits (count >= max, max finite) are handled;
 				 * unbounded VARs stay for advance phase.
 				 *
@@ -841,10 +842,10 @@ nfa_match(WindowAggState *winstate, RPRNFAContext *ctx, bool *varMatched)
 				 * to the next outer END.  The loop below walks this chain.
 				 *
 				 * ABSORBABLE_BRANCH marks elements inside the absorbable
-				 * region; ABSORBABLE marks the outermost judgment point where
-				 * count-dominance is evaluated.  We chain through BRANCH
-				 * elements until reaching the ABSORBABLE point or an element
-				 * that can still loop (count < max).
+				 * region; ABSORBABLE marks the outermost comparison point
+				 * where count-dominance is evaluated.  We chain through
+				 * BRANCH elements until reaching the ABSORBABLE point or an
+				 * element that can still loop (count < max).
 				 */
 				if (RPRElemIsAbsorbableBranch(elem) &&
 					!RPRElemIsAbsorbable(elem) &&
@@ -876,7 +877,7 @@ nfa_match(WindowAggState *winstate, RPRNFAContext *ctx, bool *varMatched)
 
 					/*
 					 * Chain through END elements within the absorbable region
-					 * (ABSORBABLE_BRANCH) until reaching the judgment point
+					 * (ABSORBABLE_BRANCH) until reaching the comparison point
 					 * (ABSORBABLE).  Continue only on must-exit path (count
 					 * >= max) with END next.
 					 */
@@ -892,9 +893,9 @@ nfa_match(WindowAggState *winstate, RPRNFAContext *ctx, bool *varMatched)
 						/*
 						 * Exit this intermediate group: clear its own count
 						 * (count-clear policy).  It sits below the absorbable
-						 * judgment point, so it is excluded from the
-						 * dominance comparison; the judgment point where the
-						 * chain stops keeps its count.
+						 * comparison point, so it is excluded from the
+						 * dominance comparison; the comparison point where
+						 * the chain stops keeps its count.
 						 */
 						state->counts[endDepth] = 0;
 
diff --git a/src/backend/optimizer/plan/rpr.c b/src/backend/optimizer/plan/rpr.c
index 597a966c7b1..ebba8e50b1d 100644
--- a/src/backend/optimizer/plan/rpr.c
+++ b/src/backend/optimizer/plan/rpr.c
@@ -19,7 +19,7 @@
  *   complexity from O(n^2) to O(n) for patterns like A+ B.
  *
  *   The absorption analysis uses two element flags:
- *   - RPR_ELEM_ABSORBABLE: marks WHERE to compare (judgment point)
+ *   - RPR_ELEM_ABSORBABLE: marks WHERE to compare (comparison point)
  *   - RPR_ELEM_ABSORBABLE_BRANCH: marks the absorbable region
  *
  *   See computeAbsorbability() and the detailed comments before
@@ -1484,7 +1484,7 @@ finalizeRPRPattern(RPRPattern *result)
  *   than Ctx2's match (1 to current). So Ctx2 can be safely eliminated.
  *
  * Two Flags:
- *   1. RPR_ELEM_ABSORBABLE - "Absorption judgment point"
+ *   1. RPR_ELEM_ABSORBABLE - "Absorption comparison point"
  *      WHERE contexts can be compared for absorption.
  *      - Simple unbounded VAR (A+): the VAR element itself
  *      - Unbounded GROUP ((A B)+): the END element only
@@ -1506,20 +1506,20 @@ finalizeRPRPattern(RPRPattern *result)
  *                -> Both at END, comparable! Ctx1 absorbs Ctx2.
  *
  *   Contexts synchronize at END every group-length rows. Therefore:
- *   - ABSORBABLE marks END as judgment point (where to compare)
+ *   - ABSORBABLE marks END as comparison point (where to compare)
  *   - ABSORBABLE_BRANCH keeps state.isAbsorbable=true through A->B->END
  *
  * Pattern Examples:
  *
  *   Pattern: A+ B
- *   Element 0 (A): ABSORBABLE | ABSORBABLE_BRANCH  <- judgment point
+ *   Element 0 (A): ABSORBABLE | ABSORBABLE_BRANCH  <- comparison point
  *   Element 1 (B): (none)
  *   -> Compare at A every row. When contexts move to B, absorption stops.
  *
  *   Pattern: (A B)+ C
  *   Element 0 (A): ABSORBABLE_BRANCH
  *   Element 1 (B): ABSORBABLE_BRANCH
- *   Element 2 (END): ABSORBABLE | ABSORBABLE_BRANCH  <- judgment point
+ *   Element 2 (END): ABSORBABLE | ABSORBABLE_BRANCH  <- comparison point
  *   Element 3 (C): (none)
  *   -> Compare at END every 2 rows. When contexts move to C, absorption stops.
  *
@@ -1629,7 +1629,7 @@ isFixedLengthChildren(RPRPattern *pattern, RPRElemIdx idx, RPRDepth scopeDepth)
  *      All children must have min == max (recursively for nested subgroups).
  *      This is equivalent to unrolling to {1,1} VARs, e.g., (A B B)+ C.
  *      All elements within the group get ABSORBABLE_BRANCH.
- *      Only the unbounded END gets ABSORBABLE (judgment point).
+ *      Only the unbounded END gets ABSORBABLE (comparison point).
  *      Examples:
  *        (A B{2})+ C          - B{2} has min==max, step=3
  *        (A (B C){2} D)+ E    - nested {2} subgroup, step=6
@@ -1791,7 +1791,7 @@ computeAbsorbabilityRecursive(RPRPattern *pattern, RPRElemIdx startIdx,
  * decrease property required for safe absorption.
  *
  * This function sets two flags:
- *   RPR_ELEM_ABSORBABLE: Absorption judgment point
+ *   RPR_ELEM_ABSORBABLE: Absorption comparison point
  *     - Simple unbounded VAR: the VAR itself (e.g., A in A+)
  *     - Unbounded GROUP: the END element (e.g., END in (A B)+)
  *   RPR_ELEM_ABSORBABLE_BRANCH: All elements in absorbable region
diff --git a/src/include/optimizer/rpr.h b/src/include/optimizer/rpr.h
index 23763442b65..83d3cd29b07 100644
--- a/src/include/optimizer/rpr.h
+++ b/src/include/optimizer/rpr.h
@@ -53,7 +53,7 @@
  * optimizer/plan/rpr.c.
  */
 #define RPR_ELEM_ABSORBABLE_BRANCH	0x04	/* element in absorbable region */
-#define RPR_ELEM_ABSORBABLE			0x08	/* absorption judgment point */
+#define RPR_ELEM_ABSORBABLE			0x08	/* absorption comparison point */
 
 /* Accessor macros for RPRPatternElement */
 #define RPRElemIsReluctant(e)			(((e)->flags & RPR_ELEM_RELUCTANT) != 0)
diff --git a/src/test/regress/expected/rpr_base.out b/src/test/regress/expected/rpr_base.out
index 80fabde514c..b385e972e7f 100644
--- a/src/test/regress/expected/rpr_base.out
+++ b/src/test/regress/expected/rpr_base.out
@@ -5472,9 +5472,9 @@ WINDOW w AS (ORDER BY id ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
 -- Absorption Flag Display Tests
 -- ============================================================
 -- Tests absorption marker display in EXPLAIN output
--- Markers: ' = branch element, " = judgment point
+-- Markers: ' = branch element, " = comparison point
 -- Files: explain.c (append_rpr_quantifier, deparse_rpr_pattern)
--- Simple VAR: A+ -> a+" (judgment point)
+-- Simple VAR: A+ -> a+" (comparison point)
 EXPLAIN (COSTS OFF)
 SELECT COUNT(*) OVER w FROM rpr_plan
 WINDOW w AS (ORDER BY id ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
@@ -5490,7 +5490,7 @@ WINDOW w AS (ORDER BY id ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
          ->  Seq Scan on rpr_plan
 (7 rows)
 
--- GROUP unbounded: (A B)+ -> (a' b')+" (branch + judgment)
+-- GROUP unbounded: (A B)+ -> (a' b')+" (branch + comparison)
 EXPLAIN (COSTS OFF)
 SELECT COUNT(*) OVER w FROM rpr_plan
 WINDOW w AS (ORDER BY id ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
diff --git a/src/test/regress/sql/rpr_base.sql b/src/test/regress/sql/rpr_base.sql
index 21840aa77be..af498fffb66 100644
--- a/src/test/regress/sql/rpr_base.sql
+++ b/src/test/regress/sql/rpr_base.sql
@@ -3254,16 +3254,16 @@ WINDOW w AS (ORDER BY id ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
 -- Absorption Flag Display Tests
 -- ============================================================
 -- Tests absorption marker display in EXPLAIN output
--- Markers: ' = branch element, " = judgment point
+-- Markers: ' = branch element, " = comparison point
 -- Files: explain.c (append_rpr_quantifier, deparse_rpr_pattern)
 
--- Simple VAR: A+ -> a+" (judgment point)
+-- Simple VAR: A+ -> a+" (comparison point)
 EXPLAIN (COSTS OFF)
 SELECT COUNT(*) OVER w FROM rpr_plan
 WINDOW w AS (ORDER BY id ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
              AFTER MATCH SKIP PAST LAST ROW PATTERN (A+) DEFINE A AS val > 0);
 
--- GROUP unbounded: (A B)+ -> (a' b')+" (branch + judgment)
+-- GROUP unbounded: (A B)+ -> (a' b')+" (branch + comparison)
 EXPLAIN (COSTS OFF)
 SELECT COUNT(*) OVER w FROM rpr_plan
 WINDOW w AS (ORDER BY id ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
-- 
2.50.1 (Apple Git-155)