Hi Henson,
> Hi Tatsuo,
>
> Here are six incremental patches on top of v43.
>
> nocfbot-0001 through nocfbot-0004 are the same patches from the
> previous round (32-bit test fix, PREV/NEXT restriction, ALT lexical
> ordering, reluctant quantifiers).
>
> nocfbot-0005: Detect zero-consumption NFA cycles
>
> Adds a per-element visited bitmap to detect zero-consumption cycles
> during DFS epsilon expansion. Before each state's DFS, the bitmap
> is cleared; as nfa_advance_state() recurses through epsilon
> transitions, each elemIdx is marked visited. If the same elemIdx
> is reached again within the same DFS, it means an epsilon-only
> loop -- the state is freed immediately.
>
> The ad-hoc (count == 0 && min == 0) exit condition in
> nfa_advance_end() is removed. The FIXME test cases are resolved
> and renamed to "Zero-Consumption Cycle Detection".
>
> nocfbot-0006: Allow A{0} quantifier
>
> With cycle detection in place, this becomes straightforward.
> Lowers the {n} bound minimum from 1 to 0. A{0} is treated as an
> epsilon transition -- the variable is skipped entirely.
Great!
> Next I plan to work on test reorganization, cross-database result
> comparison, and a review pass over the NFA executor.
Looking forward to seeing next patches.
BTW, in create_windowagg_plan (createplan.c),
around:
/* Build RPR pattern and filter defineClause */
collectPatternVariables, filterDefineClause and buildRPRPattern are
called in a block without any if or any other conditional
statements. This is an unusual codiing style in PostgreSQL. I suggest
to fix this. Attached is a proposed patch for this.
Best regards,
--
Tatsuo Ishii
SRA OSS K.K.
English: http://www.sraoss.co.jp/index_en/
Japanese:http://www.sraoss.co.jp
diff --git a/src/backend/optimizer/plan/createplan.c
b/src/backend/optimizer/plan/createplan.c
index bbc2c7e71f4..e7aafc89700 100644
--- a/src/backend/optimizer/plan/createplan.c
+++ b/src/backend/optimizer/plan/createplan.c
@@ -2484,6 +2484,10 @@ create_windowagg_plan(PlannerInfo *root, WindowAggPath
*best_path)
Oid *ordOperators;
Oid *ordCollations;
ListCell *lc;
+ List *defineVariableList = NIL;
+ List *filteredDefineClause = NIL;
+ RPRPattern *compiledPattern = NULL;
+
/*
* Choice of tlist here is motivated by the fact that WindowAgg will be
@@ -2535,50 +2539,45 @@ create_windowagg_plan(PlannerInfo *root, WindowAggPath
*best_path)
}
/* Build RPR pattern and filter defineClause */
+ if (wc->rpPattern)
{
- List *defineVariableList = NIL;
- List *filteredDefineClause = NIL;
- RPRPattern *compiledPattern = NULL;
-
- if (wc->rpPattern)
- {
- List *patternVars;
+ List *patternVars;
- /*
- * Filter defineClause to include only variables used
in PATTERN.
- * This eliminates unnecessary DEFINE evaluations at
runtime.
- */
- patternVars = collectPatternVariables(wc->rpPattern);
- filteredDefineClause =
filterDefineClause(wc->defineClause,
-
patternVars,
-
&defineVariableList);
-
- compiledPattern = buildRPRPattern(wc->rpPattern,
-
defineVariableList,
-
wc->rpSkipTo,
-
wc->frameOptions);
- }
-
- /* And finally we can make the WindowAgg node */
- plan = make_windowagg(tlist,
- wc,
- partNumCols,
- partColIdx,
- partOperators,
- partCollations,
- ordNumCols,
- ordColIdx,
- ordOperators,
- ordCollations,
-
best_path->runCondition,
- wc->rpSkipTo,
- compiledPattern,
- filteredDefineClause,
- best_path->qual,
- best_path->topwindow,
- subplan);
+ /*
+ * Filter defineClause to include only variables used in
PATTERN. This
+ * eliminates unnecessary DEFINE evaluations at runtime.
+ */
+ patternVars = collectPatternVariables(wc->rpPattern);
+ filteredDefineClause = filterDefineClause(wc->defineClause,
+
patternVars,
+
&defineVariableList);
+
+ /* Compile and optimize RPR patterns */
+ compiledPattern = buildRPRPattern(wc->rpPattern,
+
defineVariableList,
+
wc->rpSkipTo,
+
wc->frameOptions);
}
+ /* And finally we can make the WindowAgg node */
+ plan = make_windowagg(tlist,
+ wc,
+ partNumCols,
+ partColIdx,
+ partOperators,
+ partCollations,
+ ordNumCols,
+ ordColIdx,
+ ordOperators,
+ ordCollations,
+ best_path->runCondition,
+ wc->rpSkipTo,
+ compiledPattern,
+ filteredDefineClause,
+ best_path->qual,
+ best_path->topwindow,
+ subplan);
+
copy_generic_path_info(&plan->plan, (Path *) best_path);
return plan;
