nocfbot-0003-alt-lexical-order.txt
text/plain
Filename: nocfbot-0003-alt-lexical-order.txt
Type: text/plain
Part: 2
Message:
Re: Row pattern recognition
From cbf4da013b2cb0ffe2a1496e7f9467f1dc02997f Mon Sep 17 00:00:00 2001
From: Henson Choi <assam258@gmail.com>
Date: Fri, 20 Feb 2026 09:18:21 +0900
Subject: [PATCH 03/10] Fix ALT lexical ordering via DFS early termination,
remove altPriority
---
src/backend/executor/nodeWindowAgg.c | 169 +++++++++-------------
src/include/nodes/execnodes.h | 7 -
src/test/regress/expected/rpr_base.out | 2 +-
src/test/regress/expected/rpr_explain.out | 40 +++++
src/test/regress/expected/rpr_nfa.out | 92 ++++--------
src/test/regress/sql/rpr_explain.sql | 24 +++
src/test/regress/sql/rpr_nfa.sql | 70 +++------
7 files changed, 186 insertions(+), 218 deletions(-)
diff --git a/src/backend/executor/nodeWindowAgg.c b/src/backend/executor/nodeWindowAgg.c
index 9b2c4b6a1d7..96b2cd4b9c4 100644
--- a/src/backend/executor/nodeWindowAgg.c
+++ b/src/backend/executor/nodeWindowAgg.c
@@ -265,8 +265,7 @@ static RPRNFAState *nfa_state_alloc(WindowAggState *winstate);
static void nfa_state_free(WindowAggState *winstate, RPRNFAState *state);
static void nfa_state_free_list(WindowAggState *winstate, RPRNFAState *list);
static RPRNFAState *nfa_state_create(WindowAggState *winstate, int16 elemIdx,
- int16 altPriority, int32 *counts,
- bool sourceAbsorbable);
+ int32 *counts, bool sourceAbsorbable);
static bool nfa_states_equal(WindowAggState *winstate, RPRNFAState *s1,
RPRNFAState *s2);
static bool nfa_add_state_unique(WindowAggState *winstate, RPRNFAContext *ctx,
@@ -5188,14 +5187,14 @@ nfa_state_free_list(WindowAggState *winstate, RPRNFAState *list)
/*
* nfa_state_create
*
- * Create a new state with given elemIdx, altPriority and counts.
+ * Create a new state with given elemIdx and counts.
* isAbsorbable is computed immediately: inherited AND new element's flag.
* Monotonic property: once false, stays false through all transitions.
*
* Caller is responsible for linking the returned state.
*/
static RPRNFAState *
-nfa_state_create(WindowAggState *winstate, int16 elemIdx, int16 altPriority,
+nfa_state_create(WindowAggState *winstate, int16 elemIdx,
int32 *counts, bool sourceAbsorbable)
{
RPRPattern *pattern = winstate->rpPattern;
@@ -5204,7 +5203,6 @@ nfa_state_create(WindowAggState *winstate, int16 elemIdx, int16 altPriority,
RPRPatternElement *elem = &pattern->elements[elemIdx];
state->elemIdx = elemIdx;
- state->altPriority = altPriority;
if (counts != NULL && maxDepth > 0)
memcpy(state->counts, counts, sizeof(int32) * maxDepth);
@@ -5249,7 +5247,7 @@ nfa_states_equal(WindowAggState *winstate, RPRNFAState *s1, RPRNFAState *s2)
*
* Add a state to ctx->states at the END, only if no duplicate exists.
* Returns true if state was added, false if duplicate found (state is freed).
- * Earlier states have lower altPriority (lexical order), so existing wins.
+ * Earlier states have better lexical order (DFS traversal order), so existing wins.
*/
static bool
nfa_add_state_unique(WindowAggState *winstate, RPRNFAContext *ctx, RPRNFAState *state)
@@ -5286,96 +5284,42 @@ nfa_add_state_unique(WindowAggState *winstate, RPRNFAContext *ctx, RPRNFAState *
/*
* nfa_add_matched_state
*
- * Record a matched state following SQL standard semantics.
- * Lexical order (lower altPriority) wins first. Among same lexical order,
- * longer match wins (greedy).
+ * Record a state that reached FIN, replacing any previous match.
*
- * FIXME: altPriority is a single value that only tracks the last ALT choice.
- * For patterns with repeated or nested ALTs like (A|B)+, this cannot correctly
- * implement SQL standard lexical order, which requires comparing the full path
- * from left to right. For example:
- * Pattern: (A | B)+
- * Path "A B A" vs "B A B"
- * Current: compares last choice (A vs B) → altPriority 10 vs 20
- * Correct: should compare first choice (A < B) → "A B A" wins
- *
- * A classifier structure tracking the entire ALT path is required for correct
- * implementation. Without it, patterns with repeated or nested ALTs will
- * produce incorrect match selection.
+ * For SKIP PAST LAST ROW, also prune subsequent contexts whose start row
+ * falls within the match range, as they cannot produce output rows.
*/
static void
nfa_add_matched_state(WindowAggState *winstate, RPRNFAContext *ctx,
RPRNFAState *state, int64 matchEndRow)
{
- bool shouldUpdate = false;
+ if (ctx->matchedState != NULL)
+ nfa_state_free(winstate, ctx->matchedState);
- if (ctx->matchedState == NULL)
- shouldUpdate = true;
- else if (state->altPriority < ctx->matchedState->altPriority)
- shouldUpdate = true; /* Better lexical order wins */
- else if (state->altPriority == ctx->matchedState->altPriority &&
- matchEndRow > ctx->matchEndRow)
- shouldUpdate = true; /* Same lexical order, longer wins */
+ ctx->matchedState = state;
+ state->next = NULL;
+ ctx->matchEndRow = matchEndRow;
- if (shouldUpdate)
+ /* Prune contexts that started within this match's range */
+ if (winstate->rpSkipTo == ST_PAST_LAST_ROW)
{
- /* Free old matchedState if exists */
- if (ctx->matchedState != NULL)
- nfa_state_free(winstate, ctx->matchedState);
+ RPRNFAContext *nextCtx;
+ int64 skippedLen;
- /* Take ownership of the new state */
- ctx->matchedState = state;
- state->next = NULL;
- ctx->matchEndRow = matchEndRow;
-
- /*----------
- * SKIP PAST LAST ROW: eagerly prune contexts within match range.
- *
- * This function is called whenever a FIN state is reached, including
- * during greedy matching when intermediate (shorter) matches are
- * found. Each time we update matchEndRow (whether extending a greedy
- * match or finding a new match), we can prune pending contexts that
- * started within the current match range.
- *
- * SKIP PAST LAST ROW uses lexical order (matchStartRow). Therefore,
- * any pending context that started at or before matchEndRow can never
- * produce a valid output row - it would be skipped anyway per SQL
- * standard.
- *
- * Example (greedy matching in progress):
- * Pattern: START UP+
- * Rows: 1 2 3 4 5
- * Context A starts at row 1:
- * - Matches START UP (rows 1-2) → matchEndRow=2 → prune Context B(row 2)
- * - Matches START UP UP (rows 1-3) → matchEndRow=3 → prune Context C(row 3)
- * - Continues greedy extension while pruning incrementally
- *----------
- */
- if (winstate->rpSkipTo == ST_PAST_LAST_ROW)
+ while (ctx->next != NULL &&
+ ctx->next->matchStartRow <= matchEndRow)
{
- RPRNFAContext *nextCtx;
- int64 skippedLen;
-
- while (ctx->next != NULL &&
- ctx->next->matchStartRow <= matchEndRow)
- {
- nextCtx = ctx->next;
- ctx->next = ctx->next->next;
+ nextCtx = ctx->next;
+ ctx->next = ctx->next->next;
- Assert(nextCtx->lastProcessedRow >= nextCtx->matchStartRow);
- skippedLen = nextCtx->lastProcessedRow - nextCtx->matchStartRow + 1;
- nfa_record_context_skipped(winstate, skippedLen);
+ Assert(nextCtx->lastProcessedRow >= nextCtx->matchStartRow);
+ skippedLen = nextCtx->lastProcessedRow - nextCtx->matchStartRow + 1;
+ nfa_record_context_skipped(winstate, skippedLen);
- nfa_context_free(winstate, nextCtx);
- }
- if (ctx->next == NULL)
- winstate->nfaContextTail = ctx;
+ nfa_context_free(winstate, nextCtx);
}
- }
- else
- {
- /* This state didn't win, free it */
- nfa_state_free(winstate, state);
+ if (ctx->next == NULL)
+ winstate->nfaContextTail = ctx;
}
}
@@ -6124,8 +6068,7 @@ nfa_route_to_elem(WindowAggState *winstate, RPRNFAContext *ctx,
RPRNFAState *skipState;
skipState = nfa_state_create(winstate, nextElem->next,
- state->altPriority, state->counts,
- state->isAbsorbable);
+ state->counts, state->isAbsorbable);
nfa_advance_state(winstate, ctx, skipState, currentPos, initialAdvance);
}
}
@@ -6138,8 +6081,7 @@ nfa_route_to_elem(WindowAggState *winstate, RPRNFAContext *ctx,
/*
* nfa_advance_alt
*
- * Handle ALT element: expand all branches in lexical order (DFS).
- * Sets altPriority to element index to preserve lexical order for match selection.
+ * Handle ALT element: expand all branches in lexical order via DFS.
*/
static void
nfa_advance_alt(WindowAggState *winstate, RPRNFAContext *ctx,
@@ -6163,13 +6105,12 @@ nfa_advance_alt(WindowAggState *winstate, RPRNFAContext *ctx,
if (first)
{
state->elemIdx = altIdx;
- state->altPriority = altIdx;
newState = state;
first = false;
}
else
{
- newState = nfa_state_create(winstate, altIdx, altIdx,
+ newState = nfa_state_create(winstate, altIdx,
state->counts, state->isAbsorbable);
}
@@ -6204,7 +6145,7 @@ nfa_advance_begin(WindowAggState *winstate, RPRNFAContext *ctx,
/* Optional group: create skip path (but don't route yet) */
if (elem->min == 0)
{
- skipState = nfa_state_create(winstate, elem->jump, state->altPriority,
+ skipState = nfa_state_create(winstate, elem->jump,
state->counts, state->isAbsorbable);
}
@@ -6286,21 +6227,15 @@ nfa_advance_end(WindowAggState *winstate, RPRNFAContext *ctx,
* Between min and max (with at least one iteration) - can exit or
* loop
*/
- RPRElemIdx exitAltPriority;
RPRNFAState *exitState;
RPRPatternElement *jumpElem;
RPRPatternElement *nextElem;
- /* Preserve altPriority for greedy extension */
- exitAltPriority = state->altPriority;
- if (ctx->matchedState != NULL)
- exitAltPriority = ctx->matchedState->altPriority;
-
/*
* Create exit state first (need original counts before modifying
* state)
*/
- exitState = nfa_state_create(winstate, elem->next, exitAltPriority,
+ exitState = nfa_state_create(winstate, elem->next,
state->counts, state->isAbsorbable);
exitState->counts[depth] = 0;
nextElem = &elements[exitState->elemIdx];
@@ -6349,7 +6284,7 @@ nfa_advance_var(WindowAggState *winstate, RPRNFAContext *ctx,
RPRNFAState *loopState;
RPRPatternElement *nextElem;
- loopState = nfa_state_create(winstate, state->elemIdx, state->altPriority,
+ loopState = nfa_state_create(winstate, state->elemIdx,
state->counts, state->isAbsorbable);
nfa_add_state_unique(winstate, ctx, loopState);
@@ -6358,6 +6293,20 @@ nfa_advance_var(WindowAggState *winstate, RPRNFAContext *ctx,
state->elemIdx = elem->next;
nextElem = &elements[state->elemIdx];
+ /*
+ * When a quantified VAR (e.g., A+) exits directly to an outer END,
+ * increment the END's iteration count. Simple VARs (min=max=1)
+ * handle this via inline advance in nfa_match, but quantified VARs
+ * bypass that path. Only increment when the VAR actually consumed
+ * rows (count > 0) to preserve cycle prevention for zero-progress
+ * loops.
+ */
+ if (RPRElemIsEnd(nextElem) && count > 0)
+ {
+ if (state->counts[nextElem->depth] < RPR_COUNT_MAX)
+ state->counts[nextElem->depth]++;
+ }
+
nfa_route_to_elem(winstate, ctx, state, nextElem, currentPos, initialAdvance);
}
else if (canLoop)
@@ -6374,6 +6323,13 @@ nfa_advance_var(WindowAggState *winstate, RPRNFAContext *ctx,
state->elemIdx = elem->next;
nextElem = &elements[state->elemIdx];
+ /* See comment above: increment outer END count for quantified VARs */
+ if (RPRElemIsEnd(nextElem) && count > 0)
+ {
+ if (state->counts[nextElem->depth] < RPR_COUNT_MAX)
+ state->counts[nextElem->depth]++;
+ }
+
nfa_route_to_elem(winstate, ctx, state, nextElem, currentPos, initialAdvance);
}
}
@@ -6382,9 +6338,7 @@ nfa_advance_var(WindowAggState *winstate, RPRNFAContext *ctx,
* nfa_advance_state
*
* Recursively process a single state through epsilon transitions.
- * Uses DFS traversal to maintain lexical order: lower altPriority paths
- * are fully processed before higher altPriority paths, ensuring states
- * are added to ctx->states in lexical order.
+ * DFS traversal ensures states are added to ctx->states in lexical order.
*/
static void
nfa_advance_state(WindowAggState *winstate, RPRNFAContext *ctx,
@@ -6443,13 +6397,26 @@ nfa_advance(WindowAggState *winstate, RPRNFAContext *ctx, int64 currentPos,
ctx->states = NULL; /* Will rebuild */
- /* Process each state in order */
+ /* Process each state in lexical order (DFS order from previous advance) */
while (states != NULL)
{
+ RPRNFAState *savedMatchedState = ctx->matchedState;
+
state = states;
states = states->next;
state->next = NULL;
nfa_advance_state(winstate, ctx, state, currentPos, initialAdvance);
+
+ /*
+ * Early termination: if a FIN was newly reached in this advance,
+ * remaining old states have worse lexical order and can be pruned.
+ * Only check for new FIN arrivals (not ones from previous rows).
+ */
+ if (ctx->matchedState != savedMatchedState && states != NULL)
+ {
+ nfa_state_free_list(winstate, states);
+ break;
+ }
}
}
diff --git a/src/include/nodes/execnodes.h b/src/include/nodes/execnodes.h
index cd6f794f62b..9a1561fce7e 100644
--- a/src/include/nodes/execnodes.h
+++ b/src/include/nodes/execnodes.h
@@ -2523,21 +2523,14 @@ typedef enum WindowAggStatus
* RPRNFAState - single NFA state for pattern matching
*
* counts[] tracks repetition counts at each nesting depth.
- * altPriority tracks lexical order for alternation (lower = earlier alternative).
*
* isAbsorbable tracks if state is in absorbable region (ABSORBABLE_BRANCH).
* Monotonic property: once false, stays false (can't re-enter region).
- *
- * Absorption comparison uses elemIdx and counts[depth] directly because:
- * - VAR elements consume a row, forcing states to wait for next row
- * - END loop puts states at group start with iteration count preserved
- * - At row end, comparable states are at the same position (elemIdx)
*/
typedef struct RPRNFAState
{
struct RPRNFAState *next; /* next state in linked list */
int16 elemIdx; /* current pattern element index */
- int16 altPriority; /* lexical order priority (lower = preferred) */
bool isAbsorbable; /* true if state is in absorbable region */
int32 counts[FLEXIBLE_ARRAY_MEMBER]; /* repetition counts by depth */
} RPRNFAState;
diff --git a/src/test/regress/expected/rpr_base.out b/src/test/regress/expected/rpr_base.out
index 1d42af15980..d317ec70c8d 100644
--- a/src/test/regress/expected/rpr_base.out
+++ b/src/test/regress/expected/rpr_base.out
@@ -3703,7 +3703,7 @@ WINDOW w AS (
ORDER BY id;
id | val | cnt
----+-----+-----
- 1 | 10 | 0
+ 1 | 10 | 3
2 | 20 | 0
3 | 30 | 0
4 | 40 | 0
diff --git a/src/test/regress/expected/rpr_explain.out b/src/test/regress/expected/rpr_explain.out
index bfe4ee2ba7d..dacb8d6907f 100644
--- a/src/test/regress/expected/rpr_explain.out
+++ b/src/test/regress/expected/rpr_explain.out
@@ -676,6 +676,46 @@ WINDOW w AS (
-> Function Scan on generate_series s (actual rows=100.00 loops=1)
(9 rows)
+DROP VIEW rpr_v;
+-- Early termination: first ALT branch (A) reaches FIN immediately,
+-- pruning second branch (A B+) before it can accumulate B repetitions.
+CREATE TEMP VIEW rpr_v AS
+SELECT count(*) OVER w
+FROM generate_series(1, 100) AS s(v)
+WINDOW w AS (
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ PATTERN ((A | A B)+)
+ DEFINE A AS v = 1, B AS v > 1
+);
+SELECT line FROM unnest(string_to_array(pg_get_viewdef('rpr_v'), E'\n')) AS line WHERE line ~ 'PATTERN';
+ line
+-------------------------
+ PATTERN ((a | a b)+)
+(1 row)
+
+SELECT rpr_explain_filter('
+EXPLAIN (ANALYZE, BUFFERS OFF, COSTS OFF, TIMING OFF, SUMMARY OFF)
+SELECT count(*) OVER w
+FROM generate_series(1, 100) AS s(v)
+WINDOW w AS (
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ PATTERN ((A | A B)+)
+ DEFINE A AS v = 1, B AS v > 1
+);');
+ rpr_explain_filter
+-----------------------------------------------------------------------
+ WindowAgg (actual rows=100.00 loops=1)
+ Window: w AS (ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING)
+ Pattern: (a | a b)+
+ Storage: Memory Maximum Storage: NkB
+ NFA States: 5 peak, 204 total, 0 merged
+ NFA Contexts: 3 peak, 101 total, 99 pruned
+ NFA: 1 matched (len 1/1/1.0), 0 mismatched
+ -> Function Scan on generate_series s (actual rows=100.00 loops=1)
+(8 rows)
+
DROP VIEW rpr_v;
-- Nested quantifiers causing state growth
CREATE TEMP VIEW rpr_v AS
diff --git a/src/test/regress/expected/rpr_nfa.out b/src/test/regress/expected/rpr_nfa.out
index 46a463c2597..7d38d62ac31 100644
--- a/src/test/regress/expected/rpr_nfa.out
+++ b/src/test/regress/expected/rpr_nfa.out
@@ -1514,6 +1514,34 @@ WINDOW w AS (
4 | {_,_} | |
(4 rows)
+-- ALT lexical order takes priority over greedy (longer match).
+-- Row 1 matches both A and B; A wins by lexical order (match 1-1).
+WITH test_alt_lexical_order AS (
+ SELECT * FROM (VALUES
+ (1, ARRAY['A','B']), -- A and B both match
+ (2, ARRAY['_','C']) -- only C matches (would continue B C)
+ ) AS t(id, flags)
+)
+SELECT id, flags,
+ first_value(id) OVER w AS match_start,
+ last_value(id) OVER w AS match_end
+FROM test_alt_lexical_order
+WINDOW w AS (
+ ORDER BY id
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ PATTERN ((A | B C)+)
+ DEFINE
+ A AS 'A' = ANY(flags),
+ B AS 'B' = ANY(flags),
+ C AS 'C' = ANY(flags)
+);
+ id | flags | match_start | match_end
+----+-------+-------------+-----------
+ 1 | {A,B} | 1 | 1
+ 2 | {_,C} | |
+(2 rows)
+
-- ============================================================
-- Deep Nested Groups
-- ============================================================
@@ -2403,66 +2431,6 @@ WINDOW w AS (
-- ============================================================
-- FIXME Issues - Known Limitations
-- ============================================================
--- FIXME 1 - altPriority lexical order
-WITH test_alt_priority_repeated AS (
- SELECT * FROM (VALUES
- (1, ARRAY['A','B']), -- Both A and B match
- (2, ARRAY['A','B']),
- (3, ARRAY['A','B'])
- ) AS t(id, flags)
-)
-SELECT id, flags,
- first_value(id) OVER w AS match_start,
- last_value(id) OVER w AS match_end
-FROM test_alt_priority_repeated
-WINDOW w AS (
- ORDER BY id
- ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
- AFTER MATCH SKIP TO NEXT ROW
- PATTERN ((A | B)+)
- DEFINE
- A AS 'A' = ANY(flags),
- B AS 'B' = ANY(flags)
-);
- id | flags | match_start | match_end
-----+-------+-------------+-----------
- 1 | {A,B} | 1 | 3
- 2 | {A,B} | 2 | 3
- 3 | {A,B} | 3 | 3
-(3 rows)
-
--- FIXME 1 - Nested ALT lexical order
-WITH test_alt_priority_nested AS (
- SELECT * FROM (VALUES
- (1, ARRAY['A','B']),
- (2, ARRAY['C','D']),
- (3, ARRAY['A','B']),
- (4, ARRAY['C','D'])
- ) AS t(id, flags)
-)
-SELECT id, flags,
- first_value(id) OVER w AS match_start,
- last_value(id) OVER w AS match_end
-FROM test_alt_priority_nested
-WINDOW w AS (
- ORDER BY id
- ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
- AFTER MATCH SKIP TO NEXT ROW
- PATTERN (((A | B) (C | D))+)
- DEFINE
- A AS 'A' = ANY(flags),
- B AS 'B' = ANY(flags),
- C AS 'C' = ANY(flags),
- D AS 'D' = ANY(flags)
-);
- id | flags | match_start | match_end
-----+-------+-------------+-----------
- 1 | {A,B} | 1 | 4
- 2 | {C,D} | |
- 3 | {A,B} | 3 | 4
- 4 | {C,D} | |
-(4 rows)
-
-- FIXME 2 - Cycle prevention at count > 0
WITH test_cycle_nonzero AS (
SELECT * FROM (VALUES
@@ -2516,8 +2484,8 @@ WINDOW w AS (
);
id | flags | match_start | match_end
----+-------+-------------+-----------
- 1 | {A} | 1 | 2
- 2 | {B} | 2 | 2
+ 1 | {A} | 1 | 3
+ 2 | {B} | 2 | 3
3 | {A} | 3 | 3
4 | {C} | |
(4 rows)
diff --git a/src/test/regress/sql/rpr_explain.sql b/src/test/regress/sql/rpr_explain.sql
index ea8c39b991e..d017a2292d2 100644
--- a/src/test/regress/sql/rpr_explain.sql
+++ b/src/test/regress/sql/rpr_explain.sql
@@ -451,6 +451,30 @@ WINDOW w AS (
);');
DROP VIEW rpr_v;
+-- Early termination: first ALT branch (A) reaches FIN immediately,
+-- pruning second branch (A B+) before it can accumulate B repetitions.
+CREATE TEMP VIEW rpr_v AS
+SELECT count(*) OVER w
+FROM generate_series(1, 100) AS s(v)
+WINDOW w AS (
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ PATTERN ((A | A B)+)
+ DEFINE A AS v = 1, B AS v > 1
+);
+SELECT line FROM unnest(string_to_array(pg_get_viewdef('rpr_v'), E'\n')) AS line WHERE line ~ 'PATTERN';
+SELECT rpr_explain_filter('
+EXPLAIN (ANALYZE, BUFFERS OFF, COSTS OFF, TIMING OFF, SUMMARY OFF)
+SELECT count(*) OVER w
+FROM generate_series(1, 100) AS s(v)
+WINDOW w AS (
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ PATTERN ((A | A B)+)
+ DEFINE A AS v = 1, B AS v > 1
+);');
+DROP VIEW rpr_v;
+
-- Nested quantifiers causing state growth
CREATE TEMP VIEW rpr_v AS
SELECT count(*) OVER w
diff --git a/src/test/regress/sql/rpr_nfa.sql b/src/test/regress/sql/rpr_nfa.sql
index 9573d1dab3b..e9894cfa691 100644
--- a/src/test/regress/sql/rpr_nfa.sql
+++ b/src/test/regress/sql/rpr_nfa.sql
@@ -1079,6 +1079,29 @@ WINDOW w AS (
D AS 'D' = ANY(flags)
);
+-- ALT lexical order takes priority over greedy (longer match).
+-- Row 1 matches both A and B; A wins by lexical order (match 1-1).
+WITH test_alt_lexical_order AS (
+ SELECT * FROM (VALUES
+ (1, ARRAY['A','B']), -- A and B both match
+ (2, ARRAY['_','C']) -- only C matches (would continue B C)
+ ) AS t(id, flags)
+)
+SELECT id, flags,
+ first_value(id) OVER w AS match_start,
+ last_value(id) OVER w AS match_end
+FROM test_alt_lexical_order
+WINDOW w AS (
+ ORDER BY id
+ ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
+ AFTER MATCH SKIP PAST LAST ROW
+ PATTERN ((A | B C)+)
+ DEFINE
+ A AS 'A' = ANY(flags),
+ B AS 'B' = ANY(flags),
+ C AS 'C' = ANY(flags)
+);
+
-- ============================================================
-- Deep Nested Groups
-- ============================================================
@@ -1772,53 +1795,6 @@ WINDOW w AS (
-- FIXME Issues - Known Limitations
-- ============================================================
--- FIXME 1 - altPriority lexical order
-WITH test_alt_priority_repeated AS (
- SELECT * FROM (VALUES
- (1, ARRAY['A','B']), -- Both A and B match
- (2, ARRAY['A','B']),
- (3, ARRAY['A','B'])
- ) AS t(id, flags)
-)
-SELECT id, flags,
- first_value(id) OVER w AS match_start,
- last_value(id) OVER w AS match_end
-FROM test_alt_priority_repeated
-WINDOW w AS (
- ORDER BY id
- ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
- AFTER MATCH SKIP TO NEXT ROW
- PATTERN ((A | B)+)
- DEFINE
- A AS 'A' = ANY(flags),
- B AS 'B' = ANY(flags)
-);
-
--- FIXME 1 - Nested ALT lexical order
-WITH test_alt_priority_nested AS (
- SELECT * FROM (VALUES
- (1, ARRAY['A','B']),
- (2, ARRAY['C','D']),
- (3, ARRAY['A','B']),
- (4, ARRAY['C','D'])
- ) AS t(id, flags)
-)
-SELECT id, flags,
- first_value(id) OVER w AS match_start,
- last_value(id) OVER w AS match_end
-FROM test_alt_priority_nested
-WINDOW w AS (
- ORDER BY id
- ROWS BETWEEN CURRENT ROW AND UNBOUNDED FOLLOWING
- AFTER MATCH SKIP TO NEXT ROW
- PATTERN (((A | B) (C | D))+)
- DEFINE
- A AS 'A' = ANY(flags),
- B AS 'B' = ANY(flags),
- C AS 'C' = ANY(flags),
- D AS 'D' = ANY(flags)
-);
-
-- FIXME 2 - Cycle prevention at count > 0
WITH test_cycle_nonzero AS (
SELECT * FROM (VALUES
--
2.50.1 (Apple Git-155)