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executor: track memory usage for merge join #6172

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merged 4 commits into from
Mar 31, 2018
Merged

executor: track memory usage for merge join #6172

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f3f6a5b
executor: track memory usage for merge join
zz-jason Mar 28, 2018
3966391
Merge branch 'master' of https://github.com/pingcap/tidb into dev/mem…
zz-jason Mar 30, 2018
0ca81c7
add session variable
zz-jason Mar 30, 2018
1c82e10
Merge branch 'master' into dev/mem/mergejoin
coocood Mar 31, 2018
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28 changes: 23 additions & 5 deletions executor/merge_join.go
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Original file line number Diff line number Diff line change
Expand Up @@ -18,6 +18,7 @@ import (
"github.com/pingcap/tidb/expression"
"github.com/pingcap/tidb/sessionctx/stmtctx"
"github.com/pingcap/tidb/util/chunk"
"github.com/pingcap/tidb/util/memory"
"golang.org/x/net/context"
)

Expand All @@ -43,6 +44,8 @@ type MergeJoinExec struct {

innerRows []chunk.Row
innerIter4Row chunk.Iterator

memTracker *memory.Tracker
}

type mergeJoinOuterTable struct {
Expand Down Expand Up @@ -75,6 +78,8 @@ type mergeJoinInnerTable struct {
curResultInUse bool
resultQueue []*chunk.Chunk
resourceQueue []*chunk.Chunk

memTracker *memory.Tracker
}

func (t *mergeJoinInnerTable) init(ctx context.Context, chk4Reader *chunk.Chunk) (err error) {
Expand All @@ -87,6 +92,7 @@ func (t *mergeJoinInnerTable) init(ctx context.Context, chk4Reader *chunk.Chunk)
t.curRow = t.curIter.End()
t.curResultInUse = false
t.resultQueue = append(t.resultQueue, chk4Reader)
t.memTracker.Consume(chk4Reader.MemoryUsage())
t.firstRow4Key, err = t.nextRow()
t.compareFuncs = make([]chunk.CompareFunc, 0, len(t.joinKeys))
for i := range t.joinKeys {
Expand Down Expand Up @@ -125,12 +131,15 @@ func (t *mergeJoinInnerTable) rowsWithSameKey() ([]chunk.Row, error) {
func (t *mergeJoinInnerTable) nextRow() (chunk.Row, error) {
if t.curRow == t.curIter.End() {
t.reallocReaderResult()
oldMemUsage := t.curResult.MemoryUsage()
err := t.reader.NextChunk(t.ctx, t.curResult)
// error happens or no more data.
if err != nil || t.curResult.NumRows() == 0 {
t.curRow = t.curIter.End()
return t.curRow, errors.Trace(err)
}
newMemUsage := t.curResult.MemoryUsage()
t.memTracker.Consume(newMemUsage - oldMemUsage)
t.curRow = t.curIter.Begin()
}
result := t.curRow
Expand All @@ -151,7 +160,9 @@ func (t *mergeJoinInnerTable) reallocReaderResult() {
// Create a new Chunk and append it to "resourceQueue" if there is no more
// available chunk in "resourceQueue".
if len(t.resourceQueue) == 0 {
t.resourceQueue = append(t.resourceQueue, t.reader.newChunk())
newChunk := t.reader.newChunk()
t.memTracker.Consume(newChunk.MemoryUsage())
t.resourceQueue = append(t.resourceQueue, newChunk)
}

// NOTE: "t.curResult" is always the last element of "resultQueue".
Expand All @@ -165,18 +176,25 @@ func (t *mergeJoinInnerTable) reallocReaderResult() {

// Close implements the Executor Close interface.
func (e *MergeJoinExec) Close() error {
if err := e.baseExecutor.Close(); err != nil {
return errors.Trace(err)
}
return nil
e.memTracker.Detach()
e.memTracker = nil

return errors.Trace(e.baseExecutor.Close())
}

// Open implements the Executor Open interface.
func (e *MergeJoinExec) Open(ctx context.Context) error {
if err := e.baseExecutor.Open(ctx); err != nil {
return errors.Trace(err)
}

e.prepared = false
e.memTracker = memory.NewTracker(e.id, e.ctx.GetSessionVars().MemQuotaMergeJoin)
e.memTracker.AttachTo(e.ctx.GetSessionVars().StmtCtx.MemTracker)

e.innerTable.memTracker = memory.NewTracker("innerTable", -1)
e.innerTable.memTracker.AttachTo(e.memTracker)
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Do we need to detach e.innerTable.memTracker?

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No, innerTable.memTracker is a child of e.memTracker, e.memTracker is detached in Close.


return nil
}

Expand Down
5 changes: 5 additions & 0 deletions sessionctx/variable/session.go
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Expand Up @@ -283,6 +283,8 @@ type SessionVars struct {
MemQuotaQuery int64
// MemQuotaHashJoin defines the memory quota for a hash join executor.
MemQuotaHashJoin int64
// MemQuotaMergeJoin defines the memory quota for a merge join executor.
MemQuotaMergeJoin int64
// MemQuotaSort defines the memory quota for a sort executor.
MemQuotaSort int64
// MemQuotaTopn defines the memory quota for a top n executor.
Expand Down Expand Up @@ -323,6 +325,7 @@ func NewSessionVars() *SessionVars {
DMLBatchSize: DefDMLBatchSize,
MemQuotaQuery: DefTiDBMemQuotaQuery,
MemQuotaHashJoin: DefTiDBMemQuotaHashJoin,
MemQuotaMergeJoin: DefTiDBMemQuotaMergeJoin,
MemQuotaSort: DefTiDBMemQuotaSort,
MemQuotaTopn: DefTiDBMemQuotaTopn,
MemQuotaIndexLookupReader: DefTiDBMemQuotaIndexLookupReader,
Expand Down Expand Up @@ -501,6 +504,8 @@ func (s *SessionVars) SetSystemVar(name string, val string) error {
s.MemQuotaQuery = tidbOptInt64(val, DefTiDBMemQuotaQuery)
case TIDBMemQuotaHashJoin:
s.MemQuotaHashJoin = tidbOptInt64(val, DefTiDBMemQuotaHashJoin)
case TIDBMemQuotaMergeJoin:
s.MemQuotaMergeJoin = tidbOptInt64(val, DefTiDBMemQuotaMergeJoin)
case TIDBMemQuotaSort:
s.MemQuotaSort = tidbOptInt64(val, DefTiDBMemQuotaSort)
case TIDBMemQuotaTopn:
Expand Down
1 change: 1 addition & 0 deletions sessionctx/variable/sysvar.go
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Expand Up @@ -624,6 +624,7 @@ var defaultSysVars = []*SysVar{
{ScopeSession, TiDBMaxChunkSize, strconv.Itoa(DefMaxChunkSize)},
{ScopeSession, TIDBMemQuotaQuery, strconv.FormatInt(DefTiDBMemQuotaQuery, 10)},
{ScopeSession, TIDBMemQuotaHashJoin, strconv.FormatInt(DefTiDBMemQuotaHashJoin, 10)},
{ScopeSession, TIDBMemQuotaMergeJoin, strconv.FormatInt(DefTiDBMemQuotaMergeJoin, 10)},
{ScopeSession, TIDBMemQuotaSort, strconv.FormatInt(DefTiDBMemQuotaSort, 10)},
{ScopeSession, TIDBMemQuotaTopn, strconv.FormatInt(DefTiDBMemQuotaTopn, 10)},
{ScopeSession, TIDBMemQuotaIndexLookupReader, strconv.FormatInt(DefTiDBMemQuotaIndexLookupReader, 10)},
Expand Down
3 changes: 3 additions & 0 deletions sessionctx/variable/tidb_vars.go
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Expand Up @@ -116,12 +116,14 @@ const (
// The following session variables controls the memory quota during query execution.
// "tidb_mem_quota_query": control the memory quota of a query.
// "tidb_mem_quota_hashjoin": control the memory quota of "HashJoinExec".
// "tidb_mem_quota_mergejoin": control the memory quota of "MergeJoinExec".
// "tidb_mem_quota_sort": control the memory quota of "SortExec".
// "tidb_mem_quota_topn": control the memory quota of "TopNExec".
// "tidb_mem_quota_indexlookupreader": control the memory quota of "IndexLookUpExecutor".
// "tidb_mem_quota_indexlookupjoin": control the memory quota of "IndexLookUpJoin".
TIDBMemQuotaQuery = "tidb_mem_quota_query" // Bytes.
TIDBMemQuotaHashJoin = "tidb_mem_quota_hashjoin" // Bytes.
TIDBMemQuotaMergeJoin = "tidb_mem_quota_mergejoin" // Bytes.
TIDBMemQuotaSort = "tidb_mem_quota_sort" // Bytes.
TIDBMemQuotaTopn = "tidb_mem_quota_topn" // Bytes.
TIDBMemQuotaIndexLookupReader = "tidb_mem_quota_indexlookupreader" // Bytes.
Expand Down Expand Up @@ -153,6 +155,7 @@ const (
DefDMLBatchSize = 20000
DefTiDBMemQuotaQuery = 32 << 30 // 32GB.
DefTiDBMemQuotaHashJoin = 32 << 30 // 32GB.
DefTiDBMemQuotaMergeJoin = 32 << 30 // 32GB.
DefTiDBMemQuotaSort = 32 << 30 // 32GB.
DefTiDBMemQuotaTopn = 32 << 30 // 32GB.
DefTiDBMemQuotaIndexLookupReader = 32 << 30 // 32GB.
Expand Down