fix: update filter predicates for min/max aggregates only if bounds change (#20380)

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- Part of #20324 (dynamic filter update overhead for aggregates)

## Rationale for this change

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Right now `AggregateStream::maybe_update_dyn_filter()` unconditionally
updates filter predicates after every batch even without any change.
Which triggers predicate rebuilds for file pruners even though we
converge towards the bounds quite early on.

## What changes are included in this PR?

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We only conditionally update filter predicates if the bounds change.

## Are these changes tested?

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The existing test suits pass. The existing clickbench regression shows
virtually no change.

<details>
  <summary>Benchmark Results</summary>
The existing benchmarks don't reproduce this as it gets the data from
stats. So we can use a trick like `"EventDate" + 0` to force full table
scan.
 
  ```sql
  SET datafusion.execution.parquet.binary_as_string = true;
  SET datafusion.execution.parquet.pushdown_filters = false;

CREATE EXTERNAL TABLE hits STORED AS PARQUET LOCATION
'benchmarks/data/hits_partitioned';
CREATE VIEW hits_view AS SELECT "EventDate" + 0 AS "EventDate" FROM
hits;

  -- Warmup
  SELECT MIN("EventDate"), MAX("EventDate") FROM hits_view;

  -- dyn_off x5: hard-coded filter, dynamic filter disabled
SET datafusion.optimizer.enable_aggregate_dynamic_filter_pushdown =
false;
SELECT MIN("EventDate"), MAX("EventDate") FROM hits_view WHERE
"EventDate" > 0 AND "EventDate" < 99999999;
SELECT MIN("EventDate"), MAX("EventDate") FROM hits_view WHERE
"EventDate" > 0 AND "EventDate" < 99999999;
SELECT MIN("EventDate"), MAX("EventDate") FROM hits_view WHERE
"EventDate" > 0 AND "EventDate" < 99999999;
SELECT MIN("EventDate"), MAX("EventDate") FROM hits_view WHERE
"EventDate" > 0 AND "EventDate" < 99999999;
SELECT MIN("EventDate"), MAX("EventDate") FROM hits_view WHERE
"EventDate" > 0 AND "EventDate" < 99999999;

  -- dyn_on x5: dynamic filter enabled
SET datafusion.optimizer.enable_aggregate_dynamic_filter_pushdown =
true;
  SELECT MIN("EventDate"), MAX("EventDate") FROM hits_view;
  SELECT MIN("EventDate"), MAX("EventDate") FROM hits_view;
  SELECT MIN("EventDate"), MAX("EventDate") FROM hits_view;
  SELECT MIN("EventDate"), MAX("EventDate") FROM hits_view;
  SELECT MIN("EventDate"), MAX("EventDate") FROM hits_view;
  ```

  ### Before (baseline)

  | Iteration | dyn_off | dyn_on |
  |-----------|---------|--------|
  | 1 | 39ms | 44ms |
  | 2 | 39ms | 44ms |
  | 3 | 40ms | 44ms |
  | 4 | 39ms | 45ms |
  | 5 | 38ms | 45ms |
  | **Avg** | **39.0ms** | **44.4ms** |

We can see that that it's a little slow to execute with dynamic filters
on.

  ### After (this PR)

  | Iteration | dyn_off | dyn_on |
  |-----------|---------|--------|
  | 1 | 40ms | 33ms |
  | 2 | 41ms | 32ms |
  | 3 | 40ms | 32ms |
  | 4 | 42ms | 32ms |
  | 5 | 39ms | 31ms |
  | **Avg** | **40.4ms** | **32.0ms** |

  And we get approx 20% boost with the patch (in my local setup)

  </details>

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---------

Co-authored-by: Adrian Garcia Badaracco <1755071+adriangb@users.noreply.github.com>

Author: notashes

datafusion/physical-plan/src/aggregates/no_grouping.rs

@@ -161,6 +161,8 @@ impl AggregateStreamInner {
             return Ok(());
         };
 
+        let mut bounds_changed = false;
+
         for acc_info in &filter_state.supported_accumulators_info {
             let acc =
                 self.accumulators
@@ -176,20 +178,27 @@ impl AggregateStreamInner {
             let current_bound = acc.evaluate()?;
             {
                 let mut bound = acc_info.shared_bound.lock();
-                match acc_info.aggr_type {
+                let new_bound = match acc_info.aggr_type {
                     DynamicFilterAggregateType::Max => {
-                        *bound = scalar_max(&bound, &current_bound)?;
+                        scalar_max(&bound, &current_bound)?
                     }
                     DynamicFilterAggregateType::Min => {
-                        *bound = scalar_min(&bound, &current_bound)?;
+                        scalar_min(&bound, &current_bound)?
                     }
+                };
+                if new_bound != *bound {
+                    *bound = new_bound;
+                    bounds_changed = true;
                 }
             }
         }
 
-        // Step 2: Sync the dynamic filter physical expression with reader
-        let predicate = self.build_dynamic_filter_from_accumulator_bounds()?;
-        filter_state.filter.update(predicate)?;
+        // Step 2: Sync the dynamic filter physical expression with reader,
+        // but only if any bound actually changed.
+        if bounds_changed {
+            let predicate = self.build_dynamic_filter_from_accumulator_bounds()?;
+            filter_state.filter.update(predicate)?;
+        }
 
         Ok(())
     }