Fengttt spill doit.

[fengttt]

User description

What type of PR is this?

• API-change
• BUG
• Improvement
• Documentation
• Feature
• Test and CI
• Code Refactoring

Which issue(s) this PR fixes:

issue #3433

What this PR does / why we need it:

HashAgg spill. Refactor group and merge group code. Now if agg group mem usage
reached a threshold, we will spill to disk and read it back.

merge group is simply spill to network, and read it back from network.

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PR Type

Bug fix, Enhancement, Tests

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Description

• Implements comprehensive HashAgg spill-to-disk functionality with memory management and multi-pass support

• Adds new Group and MergeGroup operators with state machine architecture (Build/Eval/End states) for handling group-by and aggregation operations

• Implements bucket-based partitioning and spill file I/O with serialization/deserialization of aggregation state

• Adds distinct value tracking and serialization support across all aggregation functions (COUNT, SUM, AVG, MEDIAN, GROUP_CONCAT, APPROX_COUNT, window functions, etc.)

• Refactors batch serialization to use flexible ExtraBuf1 and ExtraBuf2 fields instead of direct Aggs field storage

• Migrates MergeGroup operator from separate mergegroup package to unified group package

• Adds reader-based vector and batch deserialization for streaming I/O support

• Implements AllGroupHash() method across all hash map implementations for spill bucket computation

• Adds utility functions for primitive type serialization/deserialization in encoding module

• Fixes hash code slice allocation logic and spill file service type handling

• Updates window operator to use colexec.ExprEvalVector instead of group.ExprEvalVector

• Adds MarshalBinary() methods to aggregation context types for serialization support

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Diagram Walkthrough

flowchart LR
  A["Input Batches"] -->|"Build Phase"| B["Group Operator<br/>Hash Table"]
  B -->|"Memory Exceeded"| C["Spill to Disk<br/>Bucket Partitioning"]
  C -->|"Serialize"| D["Spill Files"]
  D -->|"Load & Merge"| E["MergeGroup Operator"]
  E -->|"Deserialize"| F["Aggregation Results"]
  B -->|"Eval Phase"| G["Aggregation Exec<br/>Distinct Tracking"]
  G -->|"End Phase"| F
  H["Distinct Hash"] -->|"Serialize"| I["Extra Buffers"]
  I -->|"Deserialize"| J["Merged Results"]

Loading

File Walkthrough

	Relevant files
Feature	4 files exec2.go New HashAgg spill implementation with state machine            pkg/sql/colexec/group/exec2.go Implements new HashAgg spill functionality with memory management and disk spillover Adds Prepare() and Call() methods for group operator state machine (Build/Eval/End states) Implements batch building with hash table insertion and aggregation filling Adds spill-to-disk mechanism with bucket-based partitioning and multi-pass support +530/-0  helper.go Spill file I/O and hash table helper functions                      pkg/sql/colexec/group/helper.go Implements ResHashRelated struct for hash table management with insert tracking Adds spillDataToDisk() to serialize group-by batches and aggregates to spill files Implements loadSpilledData() to deserialize and merge spilled data back into memory Adds helper functions for bucket computation and spill bucket traversal +424/-0  types2.go Group operator type definitions and container management  pkg/sql/colexec/group/types2.go Defines Group and MergeGroup operator types with spill memory configuration Implements container struct with hash table, group-by batches, and spill bucket management Adds evaluation methods for group-by and aggregation arguments Provides memory management and reset/free operations for operator lifecycle +363/-0  mergeGroup.go MergeGroup operator for partial result merging with spill pkg/sql/colexec/group/mergeGroup.go Implements MergeGroup operator for merging partial aggregation results Adds Prepare() and Call() methods with spill support during merge phase Deserializes aggregation expressions from batch metadata during first merge Handles both grouped and non-grouped aggregation merging with hash table insertion +243/-0
Enhancement	29 files result.go Add distinct tracking and spill serialization to aggregation results pkg/sql/colexec/aggexec/result.go Adds hasDistinct parameter to result initialization functions for distinct value tracking Implements serialization methods marshalToBuffers() and marshalChunkToBuffer() for spill support Adds deserialization from reader via unmarshalFromReader() for loading spilled data Adds distinctFill() and distinctMerge() methods to handle distinct aggregation during merge +193/-24 batch.go Batch serialization refactoring for spill support                pkg/container/batch/batch.go Replaces Aggs field serialization with ExtraBuf1 and ExtraBuf2 for flexible metadata storage Adds UnmarshalFromReader() method for streaming deserialization from I/O readers Simplifies MarshalBinary() to delegate to MarshalBinaryWithBuffer() Updates IsEmpty() check to only consider row count, not aggregates +80/-92  types.go Aggregation function serialization interface and helpers  pkg/sql/colexec/aggexec/types.go Adds interface methods SaveIntermediateResult(), SaveIntermediateResultOfChunk(), and UnmarshalFromReader() to AggFuncExec Implements generic marshaling helpers marshalRetAndGroupsToBuffer() and marshalChunkToBuffer() for spill serialization Adds AggFuncExecExpression serialization via MarshalToBuffer() and UnmarshalFromReader() Provides generic unmarshaling helper unmarshalFromReader() for deserialization +213/-0  concat.go GROUP_CONCAT distinct handling refactoring for spill          pkg/sql/colexec/aggexec/concat.go Moves distinct hash handling from groupConcatExec to result object via distinctFill() and distinctMerge() Implements SaveIntermediateResult() and SaveIntermediateResultOfChunk() for spill serialization Adds UnmarshalFromReader() for loading spilled group_concat state Updates initialization to pass hasDistinct flag to result object +53/-34  approx_count.go APPROX_COUNT spill serialization support                                  pkg/sql/colexec/aggexec/approx_count.go Implements SaveIntermediateResult() and SaveIntermediateResultOfChunk() for HyperLogLog sketch serialization Adds UnmarshalFromReader() to deserialize sketch groups from spilled data Updates initialization to pass hasDistinct flag (false) to result object Adds validation that distinct data is nil in marshal operations +58/-6    count.go COUNT aggregation distinct and spill serialization              pkg/sql/colexec/aggexec/count.go Moves distinct hash from countColumnExec to result object via distinctFill() Implements SaveIntermediateResult() and SaveIntermediateResultOfChunk() for spill serialization Adds UnmarshalFromReader() for loading spilled count state Updates countStarExec with spill serialization methods and validation +52/-26  window.go Window function spill serialization support                            pkg/sql/colexec/aggexec/window.go Implements SaveIntermediateResult() and SaveIntermediateResultOfChunk() for rank/dense_rank/row_number serialization Adds UnmarshalFromReader() to deserialize window function groups from spilled data Defines i64Slice type with MarshalBinary() for int64 slice serialization Updates initialization to pass hasDistinct=false to result object +55/-6    median.go MEDIAN aggregation spill serialization support                      pkg/sql/colexec/aggexec/median.go Implements SaveIntermediateResult() and SaveIntermediateResultOfChunk() for median value serialization Adds UnmarshalFromReader() to deserialize median groups from spilled data Moves distinct handling to result object initialization via hasDistinct parameter Removes separate distinctHash field from median executor +50/-6    fromFixedRetFixed.go Generic fixed-to-fixed aggregation spill support                  pkg/sql/colexec/aggexec/fromFixedRetFixed.go Implements SaveIntermediateResult() and SaveIntermediateResultOfChunk() for generic fixed-to-fixed aggregation serialization Adds UnmarshalFromReader() to deserialize group contexts from spilled data Updates initialization to pass hasDistinct flag to result object Adds validation that distinct data is nil in marshal operations +33/-4    fromFixedRetBytes.go Add spill support and distinct handling to fixed-to-bytes aggregator pkg/sql/colexec/aggexec/fromFixedRetBytes.go Added imports for bytes, io, and moerr packages Modified marshal() to handle a new dist return value from marshalToBytes() with validation Added three new methods: SaveIntermediateResult(), SaveIntermediateResultOfChunk(), and UnmarshalFromReader() for spill support Updated unmarshal() to pass nil for distinct parameter Modified init() to pass info.IsDistinct() flag to initAggResultWithBytesTypeResult() and removed separate distinct hash initialization +35/-13  fromBytesRetFixed.go Add spill support to bytes-to-fixed aggregator                      pkg/sql/colexec/aggexec/fromBytesRetFixed.go Added imports for bytes, io, and moerr packages Modified marshal() to handle new dist return value with validation Added three new methods: SaveIntermediateResult(), SaveIntermediateResultOfChunk(), and UnmarshalFromReader() for spill support Updated unmarshal() to pass nil for distinct parameter Modified init() to pass false for distinct flag to initAggResultWithFixedTypeResult() +31/-3    fromBytesRetBytes.go Add spill support to bytes-to-bytes aggregator                      pkg/sql/colexec/aggexec/fromBytesRetBytes.go Added imports for bytes, io, and moerr packages Modified marshal() to handle new dist return value with validation Updated unmarshal() to pass nil for distinct parameter Added three new methods: SaveIntermediateResult(), SaveIntermediateResultOfChunk(), and UnmarshalFromReader() for spill support Modified init() to pass false for distinct flag to initAggResultWithBytesTypeResult() +34/-3    encoding.go Add I/O utility functions for type serialization                  pkg/container/types/encoding.go Added import for mpool package Added utility functions for reading/writing primitive types and bytes: WriteSizeBytes(), ReadInt64(), WriteInt64(), ReadBool(), ReadInt32(), WriteInt32(), ReadInt32AsInt(), ReadByte(), ReadByteAsInt(), ReadType(), ReadSizeBytes() These functions support serialization/deserialization with optional memory pool allocation +104/-0  vector.go Add reader-based vector deserialization method                      pkg/container/vector/vector.go Added io import Added new method UnmarshalWithReader() that deserializes a vector from an io.Reader with support for memory pool allocation Reads vector metadata (class, type, length) and data buffers (data, area, nsp) sequentially from reader +56/-0    var_pop.go Add MarshalBinary methods to var_pop aggregation contexts pkg/sql/plan/function/agg/var_pop.go Reordered imports to place math before other imports Added MarshalBinary() method to aggVarPopGroupContext, aggVarPopOfDecimalGroupContext, and aggVarPopOfDecimalCommonContext types +5/-1      evalExpression.go Add ExprEvalVector type for expression evaluation                pkg/sql/colexec/evalExpression.go Added new ExprEvalVector struct type with fields for executors, vectors, and types Added MakeEvalVector() function to create and initialize ExprEvalVector from plan expressions Added Free() and ResetForNextQuery() methods to ExprEvalVector for resource management +40/-0    avg.go Add MarshalBinary methods to avg aggregation contexts        pkg/sql/plan/function/agg/avg.go Added MarshalBinary() method to aggAvgContext type Added MarshalBinary() method to aggAvgDecimalCommonCtx type Reformatted method signatures for alignment +5/-3      distinct.go Add reader-based deserialization for distinct hash              pkg/sql/colexec/aggexec/distinct.go Added marshalToBuffers() method to serialize distinct hash maps based on flags Refactored unmarshal() to delegate to new unmarshalFromReader() method Added unmarshalFromReader() method to deserialize from io.Reader instead of byte slice +15/-0    avg_tw_result.go Add MarshalBinary methods to avg_tw_result contexts            pkg/sql/plan/function/agg/avg_tw_result.go Added MarshalBinary() method to AvgTwResultContext type Added MarshalBinary() method to AvgTwResultDecimalContext type +2/-1      avg_tw_cache.go Add MarshalBinary methods to avg_tw_cache contexts              pkg/sql/plan/function/agg/avg_tw_cache.go Added MarshalBinary() method to AvgTwCacheContext type Added MarshalBinary() method to AvgTwCacheDecimalContext type +3/-0      sum.go Add MarshalBinary method to sum aggregation context            pkg/sql/plan/function/agg/sum.go Added MarshalBinary() method to aggSumDecimal type Reformatted method signatures for alignment +3/-2      types.go Add AllGroupHash method to HashMap interface                          pkg/common/hashmap/types.go Added AllGroupHash() method signature to HashMap interface Method returns all (group, hashCode) pairs as a slice of uint64 +2/-0      string_hash_map.go Implement AllGroupHash for StringHashMap                                  pkg/container/hashtable/string_hash_map.go Added AllGroupHash() method implementation that returns hash codes for all mapped groups +12/-0    int64_hash_map.go Implement AllGroupHash for Int64HashMap                                    pkg/container/hashtable/int64_hash_map.go Added AllGroupHash() method implementation that returns hash codes for all mapped groups +12/-0    aggContext.go Add method to retrieve group contexts for marshalling        pkg/sql/colexec/aggexec/aggContext.go Added getGroupContextBinaryMarshaller() method to retrieve group contexts for binary marshalling +7/-0      aggMethod.go Add MarshalBinary to AggCanMarshal interface                          pkg/sql/colexec/aggexec/aggMethod.go Added MarshalBinary() ([]byte, error) method signature to AggCanMarshal interface +1/-0      inthashmap.go Implement AllGroupHash for IntHashMap                                        pkg/common/hashmap/inthashmap.go Added AllGroupHash() method that delegates to underlying hash map implementation +4/-0      strhashmap.go Implement AllGroupHash for StrHashMap                                        pkg/common/hashmap/strhashmap.go Added AllGroupHash() method that delegates to underlying hash map implementation +4/-0      bitmap.go Add MarshalBinary method to bitmap aggregation context      pkg/sql/plan/function/agg/bitmap.go Added MarshalBinary() method to aggBitmapGroupContext type +1/-0
Tests	4 files result_test.go Test updates for distinct parameter in result functions    pkg/sql/colexec/aggexec/result_test.go Updates test calls to pass hasDistinct parameter to result initialization functions Updates marshalToBytes() calls to handle third return value for distinct data Updates unmarshalFromBytes() calls to pass nil for distinct data parameter Fixes import ordering (testing import moved to top) +17/-14  remoterun_test.go Update test to use group.MergeGroup                                            pkg/sql/compile/remoterun_test.go Removed import of mergegroup package Changed &mergegroup.MergeGroup{} to &group.MergeGroup{} in test data +1/-18    batch_test.go Update batch tests for extra buffer fields                              pkg/container/batch/batch_test.go Reordered imports to place testing before other imports Added assertions in test to verify ExtraBuf1 and ExtraBuf2 fields are preserved during marshal/unmarshal Removed aggregation function setup from newBatch() helper Added initialization of ExtraBuf1 and ExtraBuf2 fields in test batch +9/-3      aggFrame_test.go Add MarshalBinary method to test context                                  pkg/sql/colexec/aggexec/aggFrame_test.go Added MarshalBinary() method to avgDemoCtx test type Reformatted method signatures for alignment +4/-3
Refactoring	7 files window.go Window operator refactoring for expression evaluation        pkg/sql/colexec/window/window.go Changes aggVecs and orderVecs from group.ExprEvalVector to colexec.ExprEvalVector Replaces ctr.bat.Aggs with ctr.batAggs to separate batch data from aggregation state Updates MakeEvalVector() calls to use colexec package instead of group package Removes dependency on group package for expression evaluation +12/-13  remoterun.go Migrate MergeGroup from mergegroup to group package            pkg/sql/compile/remoterun.go Removed import of mergegroup package Changed *mergegroup.MergeGroup references to *group.MergeGroup Updated mergegroup.NewArgument() call to group.NewArgumentMergeGroup() Updated function signatures for EncodeMergeGroup() and DecodeMergeGroup() to use *group.MergeGroup +5/-6      scope.go Migrate MergeGroup references and simplify optimization logic pkg/sql/compile/scope.go Removed import of mergegroup package Changed findMergeGroup() return type from *mergegroup.MergeGroup to *group.MergeGroup Updated type assertion from *mergegroup.MergeGroup to *group.MergeGroup Simplified aggOptimize() logic by removing the assignment of PartialResults and PartialResultTypes to mergeGroup +3/-7      types.go Refactor window container to use colexec.ExprEvalVector    pkg/sql/colexec/window/types.go Reordered imports to place colexec before aggexec Removed import of group package Added batAggs field to container struct for storing aggregation functions Changed orderVecs and aggVecs types from []group.ExprEvalVector to []colexec.ExprEvalVector Updated freeAggFun() to use ctr.batAggs instead of ctr.bat.Aggs +7/-6      operator.go Migrate MergeGroup construction to group package                  pkg/sql/compile/operator.go Removed import of mergegroup package Changed constructMergeGroup() return type from *mergegroup.MergeGroup to *group.MergeGroup Updated mergegroup.NewArgument() call to group.NewArgumentMergeGroup() +2/-3      compile.go Update MergeGroup type reference in compile                            pkg/sql/compile/compile.go Removed import of mergegroup package Changed *mergegroup.MergeGroup type assertion to *group.MergeGroup in compileProjection() method +1/-2      types.go Replace Aggs field with extra buffer fields in Batch          pkg/container/batch/types.go Removed import of aggexec package Replaced Aggs []aggexec.AggFuncExec field with ExtraBuf1 []byte and ExtraBuf2 []byte fields Reformatted struct field alignment +3/-4
Formatting	2 files buffer.go Reorder imports for consistency                                                    pkg/container/pSpool/buffer.go Reordered imports to place sync before other imports +2/-7      copy.go Reorder imports for consistency                                                    pkg/container/pSpool/copy.go Reordered imports to place math before other imports +2/-4
Bug fix	2 files process.go Update spill file service to return LocalFS type                  pkg/vm/process/process.go Added import for moerr package Changed GetSpillFileService() return type from fileservice.MutableFileService to *fileservice.LocalFS Added type assertion and validation to ensure spillfs is a *fileservice.LocalFS instance +10/-2    index_util.go Fix hash code slice allocation logic                                          pkg/sql/util/index_util.go Fixed hash code slice capacity check from rowCount > cap(hashCode) to rowCount > len(hashCode) Added else clause to slice hashCode to exact rowCount when capacity is sufficient +3/-1
Additional files	9 files exec.go +0/-503  exec_test.go +0/-600  execctx.go +0/-419  execctx_test.go +0/-96    types.go +0/-240  exec.go +0/-221  exec_test.go +0/-219  types.go +0/-101  top.go +0/-1

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PR Compliance Guide 🔍

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Security Compliance
⚪	Insecure spill I/O Description: Spill files are created with predictable names (UUID + bucket index) and written without explicit fsync/sync or permission hardening, and error handling ignores Write return value, risking partial writes and potential data corruption or leakage if the spill file service maps to shared storage. helper.go [160-241] Referred Code return count, kth } func (ctr *container) spillDataToDisk(proc *process.Process, parentBkt *spillBucket) error { // we only allow to spill up to spillMaxPass passes. // each pass we take spillMaskBits bits from the hashCode, and use them as the index // to select the spill bucket. Default params, 32^3 = 32768 spill buckets -- if this // is still not enough, probably we cannot do much anyway, just fail the query. if parentBkt.lv >= spillMaxPass { return moerr.NewInternalError(proc.Ctx, "spill level too deep") } lv := parentBkt.lv + 1 // initialing spill structure. if len(parentBkt.again) == 0 { parentBkt.again = make([]spillBucket, spillNumBuckets) fnuuid, _ := uuid.NewV7() // log the spill file name. logutil.Infof("spilling data to disk, level %d, file %s", parentBkt.lv, fnuuid.String()) ... (clipped 61 lines)
	Untrusted input parsing Description: Loading spilled data does not validate sizes beyond trusting encoded lengths and lacks robust EOF checks, which could allow malformed spill files to cause excessive memory allocation or panic when reading from untrusted or corrupted storage. helper.go [309-370] Referred Code var next int var nextBkt *spillBucket for next = 0; next < len(bkt.again); next++ { nextBkt = bkt.again[next].nextToLoadBkt() if nextBkt != nil { break } } if nextBkt == nil { bkt.again = nil return nil } bkt.again = bkt.again[next:] return nextBkt } func (bkt *spillBucket) free(proc *process.Process) { if bkt.file != nil { ... (clipped 41 lines)
	Unbounded aggregation growth Description: GROUP_CONCAT concatenates unbounded strings without enforcing a maximum length, enabling potential memory exhaustion when processing large distinct sets or long separators. concat.go [146-155] Referred Code x, y := exec.ret.updateNextAccessIdx(groupIndex) exec.ret.setGroupNotEmpty(x, y) if need, err := exec.ret.distinctFill(x, y, vectors, row); err != nil || !need { return err } r := exec.ret.get() if len(r) > 0 { r = append(r, exec.separator...)
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PR Code Suggestions ✨

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Category	Suggestion	Impact
Possible issue	Fix incorrect spill bucket calculation Fix the incorrect bitmask in the spill bucket calculation to ensure proper data distribution across buckets by using (1 << spillMaskBits) - 1. pkg/sql/colexec/group/helper.go [197-201] // compute spill bucket. hashCodes := ctr.hr.Hash.AllGroupHash() for i, hashCode := range hashCodes { - hashCodes[i] = (hashCode >> (64 - spillMaskBits*lv)) & (spillMaskBits - 1) + hashCodes[i] = (hashCode >> (64 - spillMaskBits*lv)) & ((1 << spillMaskBits) - 1) } Apply / Chat Suggestion importance[1-10]: 9 __ Why: The suggestion correctly identifies a critical bug in the spill bucket calculation where an incorrect bitmask (spillMaskBits - 1) would lead to poor data distribution, and provides the correct fix.	High
	Prevent panic from out-of-bounds access Correct the boundary check for group.GroupingFlag to prevent a potential panic from an out-of-bounds slice access. pkg/sql/colexec/group/types2.go [106-109] // FUBAR: check if the grouping flag length is too big, - if len(group.ctr.groupByEvaluate.Vec) >= len(group.GroupingFlag) { - return moerr.NewInternalErrorNoCtx("grouping flag length too big") + if len(group.ctr.groupByEvaluate.Vec) > len(group.GroupingFlag) { + return moerr.NewInternalErrorNoCtx("mismatch between grouping expressions and grouping flags") } Apply / Chat Suggestion importance[1-10]: 8 __ Why: The suggestion correctly identifies a logic error in a boundary check that could lead to a panic due to an out-of-bounds slice access and provides a correct fix.	Medium
	Handle potential error from write The WriteInt64 function should return the error from the underlying w.Write call instead of always returning nil. pkg/container/types/encoding.go [579-582] func WriteInt64(w io.Writer, v int64) error { - w.Write(EncodeInt64(&v)) - return nil + _, err := w.Write(EncodeInt64(&v)) + return err } Apply / Chat Suggestion importance[1-10]: 7 __ Why: The suggestion correctly identifies that an error from w.Write is ignored, which could lead to silent failures, and the proposed fix correctly propagates the error.	Medium
General	✅ Correctly free and clear aggregators Suggestion Impact: The commit changed loadSpilledData to stop using the ineffective loop variable nil assignment by replacing the cleanup with a call to ctr.resetForSpill(proc), and later reconstructing aggList and spillAggList. This achieves the intended effect of correctly freeing and resetting aggregators, albeit via a helper rather than explicit index loops and slice nil-ing. code diff: + // popped bkt must be freed. bkt := ctr.spillBkts.PopBack().Value + defer bkt.free(proc) + // reposition to the start of the file. bkt.file.Seek(0, io.SeekStart) - // reset data structures, - ctr.hr.Free0() - - // reset rowcount group by batches. - for _, gb := range ctr.groupByBatches { - gb.SetRowCount(0) - } - ctr.currBatchIdx = 0 - - // Free, will clean the resource and reuse the aggregation. - for _, ag := range ctr.aggList { - ag.Free() - } - for _, ag := range ctr.spillAggList { - ag.Free() - } - - gbBatch := ctr.createNewGroupByBatch(proc, ctr.groupByBatches[0].Vecs, aggBatchSize) + ctr.resetForSpill(proc) + ctr.aggList, err = ctr.makeAggList(proc, aggExprs) + if err != nil { + return false, err + } + ctr.spillAggList, err = ctr.makeAggList(proc, aggExprs) + if err != nil { + return false, err + } + + gbBatch := ctr.createNewGroupByBatch(proc, nil, aggBatchSize) + totalCnt := int64(0) for { Refactor the aggregator cleanup logic in loadSpilledData to correctly free resources and then set the entire slice to nil, removing the ineffective assignment to the loop variable. pkg/sql/colexec/group/helper.go [363-370] - for _, ag := range ctr.aggList { - ag.Free() - ag = nil + for i := range ctr.aggList { + ctr.aggList[i].Free() } - for _, ag := range ctr.spillAggList { - ag.Free() - ag = nil + ctr.aggList = nil + + for i := range ctr.spillAggList { + ctr.spillAggList[i].Free() } + ctr.spillAggList = nil [Suggestion processed] Suggestion importance[1-10]: 5 __ Why: The suggestion correctly points out that assigning nil to a loop variable is ineffective and misleading, proposing a cleaner way to free resources and clear the slices, which improves code clarity and correctness.	Low
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