explain with broker buffer

weed/query/engine/aggregations.go

@@ -331,6 +331,11 @@ func (comp *AggregationComputer) computeGlobalMax(spec AggregationSpec, dataSour
 
 // executeAggregationQuery handles SELECT queries with aggregation functions
 func (e *SQLEngine) executeAggregationQuery(ctx context.Context, hybridScanner *HybridMessageScanner, aggregations []AggregationSpec, stmt *sqlparser.Select) (*QueryResult, error) {
+	return e.executeAggregationQueryWithPlan(ctx, hybridScanner, aggregations, stmt, nil)
+}
+
+// executeAggregationQueryWithPlan handles SELECT queries with aggregation functions and populates execution plan
+func (e *SQLEngine) executeAggregationQueryWithPlan(ctx context.Context, hybridScanner *HybridMessageScanner, aggregations []AggregationSpec, stmt *sqlparser.Select, plan *QueryExecutionPlan) (*QueryResult, error) {
 	// Parse WHERE clause for filtering
 	var predicate func(*schema_pb.RecordValue) bool
 	var err error
@@ -373,11 +378,44 @@ func (e *SQLEngine) executeAggregationQuery(ctx context.Context, hybridScanner *
 	}
 
 	// Execute the hybrid scan to get all matching records
-	results, err := hybridScanner.Scan(ctx, hybridScanOptions)
+	var results []HybridScanResult
+	if plan != nil {
+		// EXPLAIN mode - capture broker buffer stats
+		var stats *HybridScanStats
+		results, stats, err = hybridScanner.ScanWithStats(ctx, hybridScanOptions)
 		if err != nil {
 			return &QueryResult{Error: err}, err
 		}
 
+		// Populate plan with broker buffer information
+		if stats != nil {
+			plan.BrokerBufferQueried = stats.BrokerBufferQueried
+			plan.BrokerBufferMessages = stats.BrokerBufferMessages
+			plan.BufferStartIndex = stats.BufferStartIndex
+
+			// Add broker_buffer to data sources if buffer was queried
+			if stats.BrokerBufferQueried {
+				// Check if broker_buffer is already in data sources
+				hasBrokerBuffer := false
+				for _, source := range plan.DataSources {
+					if source == "broker_buffer" {
+						hasBrokerBuffer = true
+						break
+					}
+				}
+				if !hasBrokerBuffer {
+					plan.DataSources = append(plan.DataSources, "broker_buffer")
+				}
+			}
+		}
+	} else {
+		// Normal mode - just get results
+		results, err = hybridScanner.Scan(ctx, hybridScanOptions)
+		if err != nil {
+			return &QueryResult{Error: err}, err
+		}
+	}
+
 	// Compute aggregations
 	aggResults := e.computeAggregations(results, aggregations)
 

weed/query/engine/engine.go

@@ -306,6 +306,14 @@ func (e *SQLEngine) buildHierarchicalPlan(plan *QueryExecutionPlan, err error) [
 			stats = append(stats, fmt.Sprintf("Rows Processed: %d", plan.TotalRowsProcessed))
 		}
 
+		// Broker buffer information
+		if plan.BrokerBufferQueried {
+			stats = append(stats, fmt.Sprintf("Broker Buffer Queried: Yes (%d messages)", plan.BrokerBufferMessages))
+			if plan.BufferStartIndex > 0 {
+				stats = append(stats, fmt.Sprintf("Buffer Start Index: %d (deduplication enabled)", plan.BufferStartIndex))
+			}
+		}
+
 		for i, stat := range stats {
 			if hasMoreAfterStats {
 				// More sections after Statistics, so use │   prefix
@@ -375,6 +383,8 @@ func (e *SQLEngine) formatDataSource(source string) string {
 		return "Parquet Files (full scan)"
 	case "live_logs":
 		return "Live Log Files"
+	case "broker_buffer":
+		return "Broker Buffer (real-time)"
 	default:
 		return source
 	}
@@ -441,8 +451,52 @@ func (e *SQLEngine) executeSelectStatementWithPlan(ctx context.Context, stmt *sq
 		}
 	}
 
-	// Execute the query
+	// Execute the query (handle aggregations specially for plan tracking)
-	result, err := e.executeSelectStatement(ctx, stmt)
+	var result *QueryResult
+	var err error
+
+	if hasAggregations {
+		// Extract table information for aggregation execution
+		var database, tableName string
+		if len(stmt.From) == 1 {
+			if table, ok := stmt.From[0].(*sqlparser.AliasedTableExpr); ok {
+				if tableExpr, ok := table.Expr.(sqlparser.TableName); ok {
+					tableName = tableExpr.Name.String()
+					if tableExpr.Qualifier.String() != "" {
+						database = tableExpr.Qualifier.String()
+					}
+				}
+			}
+		}
+
+		// Use current database if not specified
+		if database == "" {
+			database = e.catalog.currentDatabase
+			if database == "" {
+				database = "default"
+			}
+		}
+
+		// Create hybrid scanner for aggregation execution
+		var filerClient filer_pb.FilerClient
+		if e.catalog.brokerClient != nil {
+			filerClient, err = e.catalog.brokerClient.GetFilerClient()
+			if err != nil {
+				return &QueryResult{Error: err}, err
+			}
+		}
+
+		hybridScanner, err := NewHybridMessageScanner(filerClient, e.catalog.brokerClient, database, tableName)
+		if err != nil {
+			return &QueryResult{Error: err}, err
+		}
+
+		// Execute aggregation query with plan tracking
+		result, err = e.executeAggregationQueryWithPlan(ctx, hybridScanner, aggregations, stmt, plan)
+	} else {
+		// Regular SELECT query
+		result, err = e.executeSelectStatement(ctx, stmt)
+	}
 
 	if err == nil && result != nil {
 		// Extract table name for use in execution strategy determination

weed/query/engine/hybrid_message_scanner.go

@@ -111,7 +111,15 @@ type HybridScanResult struct {
 	Values    map[string]*schema_pb.Value // Column name -> value
 	Timestamp int64                       // Message timestamp (_ts_ns)
 	Key       []byte                      // Message key (_key)
-	Source    string                      // "live_log" or "parquet_archive"
+	Source    string                      // "live_log" or "parquet_archive" or "in_memory_broker"
+}
+
+// HybridScanStats contains statistics about data sources scanned
+type HybridScanStats struct {
+	BrokerBufferQueried  bool
+	BrokerBufferMessages int
+	BufferStartIndex     int64
+	PartitionsScanned    int
 }
 
 // ParquetColumnStats holds statistics for a single column from parquet metadata
@@ -137,7 +145,14 @@ type ParquetFileStats struct {
 // 2. Applies filtering at the lowest level for efficiency
 // 3. Handles schema evolution transparently
 func (hms *HybridMessageScanner) Scan(ctx context.Context, options HybridScanOptions) ([]HybridScanResult, error) {
+	results, _, err := hms.ScanWithStats(ctx, options)
+	return results, err
+}
+
+// ScanWithStats reads messages and returns scan statistics for execution plans
+func (hms *HybridMessageScanner) ScanWithStats(ctx context.Context, options HybridScanOptions) ([]HybridScanResult, *HybridScanStats, error) {
 	var results []HybridScanResult
+	stats := &HybridScanStats{}
 
 	// Get all partitions for this topic
 	// RESOLVED TODO: Implement proper partition discovery via MQ broker
@@ -147,14 +162,27 @@ func (hms *HybridMessageScanner) Scan(ctx context.Context, options HybridScanOpt
 		partitions = []topic.Partition{{RangeStart: 0, RangeStop: 1000}}
 	}
 
+	stats.PartitionsScanned = len(partitions)
+
 	for _, partition := range partitions {
-		partitionResults, err := hms.scanPartitionHybrid(ctx, partition, options)
+		partitionResults, partitionStats, err := hms.scanPartitionHybridWithStats(ctx, partition, options)
 		if err != nil {
-			return nil, fmt.Errorf("failed to scan partition %v: %v", partition, err)
+			return nil, stats, fmt.Errorf("failed to scan partition %v: %v", partition, err)
 		}
 
 		results = append(results, partitionResults...)
 
+		// Aggregate broker buffer stats
+		if partitionStats != nil {
+			if partitionStats.BrokerBufferQueried {
+				stats.BrokerBufferQueried = true
+			}
+			stats.BrokerBufferMessages += partitionStats.BrokerBufferMessages
+			if partitionStats.BufferStartIndex > 0 && (stats.BufferStartIndex == 0 || partitionStats.BufferStartIndex < stats.BufferStartIndex) {
+				stats.BufferStartIndex = partitionStats.BufferStartIndex
+			}
+		}
+
 		// Apply global limit across all partitions
 		if options.Limit > 0 && len(results) >= options.Limit {
 			results = results[:options.Limit]
@@ -162,18 +190,28 @@ func (hms *HybridMessageScanner) Scan(ctx context.Context, options HybridScanOpt
 		}
 	}
 
-	return results, nil
+	return results, stats, nil
 }
 
 // scanUnflushedData queries brokers for unflushed in-memory data using buffer_start deduplication
 func (hms *HybridMessageScanner) scanUnflushedData(ctx context.Context, partition topic.Partition, options HybridScanOptions) ([]HybridScanResult, error) {
+	results, _, err := hms.scanUnflushedDataWithStats(ctx, partition, options)
+	return results, err
+}
+
+// scanUnflushedDataWithStats queries brokers for unflushed data and returns statistics
+func (hms *HybridMessageScanner) scanUnflushedDataWithStats(ctx context.Context, partition topic.Partition, options HybridScanOptions) ([]HybridScanResult, *HybridScanStats, error) {
 	var results []HybridScanResult
+	stats := &HybridScanStats{}
 
 	// Skip if no broker client available
 	if hms.brokerClient == nil {
-		return results, nil
+		return results, stats, nil
 	}
 
+	// Mark that we attempted to query broker buffer
+	stats.BrokerBufferQueried = true
+
 	// Step 1: Get unflushed data from broker using buffer_start-based method
 	// This method uses buffer_start metadata to avoid double-counting with exact precision
 	unflushedEntries, err := hms.brokerClient.GetUnflushedMessages(ctx, hms.topic.Namespace, hms.topic.Name, partition, options.StartTimeNs)
@@ -182,7 +220,20 @@ func (hms *HybridMessageScanner) scanUnflushedData(ctx context.Context, partitio
 		if isDebugMode(ctx) {
 			fmt.Printf("Debug: Failed to get unflushed messages: %v\n", err)
 		}
-		return results, nil
+		// Reset queried flag on error
+		stats.BrokerBufferQueried = false
+		return results, stats, nil
+	}
+
+	// Capture stats for EXPLAIN
+	stats.BrokerBufferMessages = len(unflushedEntries)
+
+	// Debug logging for EXPLAIN mode
+	if isDebugMode(ctx) {
+		fmt.Printf("Debug: Broker buffer queried - found %d unflushed messages\n", len(unflushedEntries))
+		if len(unflushedEntries) > 0 {
+			fmt.Printf("Debug: Using buffer_start deduplication for precise real-time data\n")
+		}
 	}
 
 	// Step 2: Process unflushed entries (already deduplicated by broker)
@@ -251,7 +302,7 @@ func (hms *HybridMessageScanner) scanUnflushedData(ctx context.Context, partitio
 		fmt.Printf("Debug: Retrieved %d unflushed messages from broker\n", len(results))
 	}
 
-	return results, nil
+	return results, stats, nil
 }
 
 // convertDataMessageToRecord converts mq_pb.DataMessage to schema_pb.RecordValue
@@ -344,15 +395,29 @@ func (hms *HybridMessageScanner) discoverTopicPartitions(ctx context.Context) ([
 // 1. Unflushed in-memory data from brokers (REAL-TIME)
 // 2. Live logs + Parquet files from disk (FLUSHED/ARCHIVED)
 func (hms *HybridMessageScanner) scanPartitionHybrid(ctx context.Context, partition topic.Partition, options HybridScanOptions) ([]HybridScanResult, error) {
+	results, _, err := hms.scanPartitionHybridWithStats(ctx, partition, options)
+	return results, err
+}
+
+// scanPartitionHybridWithStats scans a specific partition and returns statistics
+func (hms *HybridMessageScanner) scanPartitionHybridWithStats(ctx context.Context, partition topic.Partition, options HybridScanOptions) ([]HybridScanResult, *HybridScanStats, error) {
 	var results []HybridScanResult
+	stats := &HybridScanStats{}
 
 	// STEP 1: Scan unflushed in-memory data from brokers (REAL-TIME)
-	unflushedResults, err := hms.scanUnflushedData(ctx, partition, options)
+	unflushedResults, unflushedStats, err := hms.scanUnflushedDataWithStats(ctx, partition, options)
 	if err != nil {
 		// Don't fail the query if broker scanning fails - just log and continue with disk data
+		if !isDebugMode(ctx) {
 			fmt.Printf("Warning: Failed to scan unflushed data from broker: %v\n", err)
+		}
 	} else {
 		results = append(results, unflushedResults...)
+		if unflushedStats != nil {
+			stats.BrokerBufferQueried = unflushedStats.BrokerBufferQueried
+			stats.BrokerBufferMessages = unflushedStats.BrokerBufferMessages
+			stats.BufferStartIndex = unflushedStats.BufferStartIndex
+		}
 	}
 
 	// STEP 2: Scan flushed data from disk (live logs + Parquet files)
@@ -436,7 +501,7 @@ func (hms *HybridMessageScanner) scanPartitionHybrid(ctx context.Context, partit
 		_, _, err = mergedReadFn(startPosition, stopTsNs, eachLogEntryFn)
 
 		if err != nil {
-			return nil, fmt.Errorf("flushed data scan failed: %v", err)
+			return nil, stats, fmt.Errorf("flushed data scan failed: %v", err)
 		}
 	}
 
@@ -458,7 +523,7 @@ func (hms *HybridMessageScanner) scanPartitionHybrid(ctx context.Context, partit
 		results = results[:options.Limit]
 	}
 
-	return results, nil
+	return results, stats, nil
 }
 
 // convertLogEntryToRecordValue converts a filer_pb.LogEntry to schema_pb.RecordValue

weed/query/engine/types.go

@@ -8,7 +8,7 @@ import (
 type QueryExecutionPlan struct {
 	QueryType           string
 	ExecutionStrategy   string                 `json:"execution_strategy"` // fast_path, full_scan, hybrid
-	DataSources         []string               `json:"data_sources"`       // parquet_files, live_logs
+	DataSources         []string               `json:"data_sources"`       // parquet_files, live_logs, broker_buffer
 	PartitionsScanned   int                    `json:"partitions_scanned"`
 	ParquetFilesScanned int                    `json:"parquet_files_scanned"`
 	LiveLogFilesScanned int                    `json:"live_log_files_scanned"`
@@ -18,6 +18,11 @@ type QueryExecutionPlan struct {
 	Aggregations        []string               `json:"aggregations,omitempty"`
 	ExecutionTimeMs     float64                `json:"execution_time_ms"`
 	Details             map[string]interface{} `json:"details,omitempty"`
+
+	// Broker buffer information
+	BrokerBufferQueried  bool  `json:"broker_buffer_queried"`
+	BrokerBufferMessages int   `json:"broker_buffer_messages"`
+	BufferStartIndex     int64 `json:"buffer_start_index,omitempty"`
 }
 
 // QueryResult represents the result of a SQL query execution