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pingcap · Dec 19, 2019 · 729e4c4 · 729e4c4
1 parent 1400ce5
commit 729e4c4
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/util/stmtsummary/statement_summary.go b/util/stmtsummary/statement_summary.go
@@ -48,6 +48,8 @@ type stmtSummaryByDigestKey struct {
 }
 
 // Hash implements SimpleLRUCache.Key.
+// Only when current SQL is `commit` do we record `prevSQL`. Otherwise, `prevSQL` is empty.
+// `prevSQL` is included in the key To distinguish different transactions.
 func (key *stmtSummaryByDigestKey) Hash() []byte {
 	if len(key.hash) == 0 {
 		key.hash = make([]byte, 0, len(key.schemaName)+len(key.digest)+len(key.prevDigest))