Wrong column type for PLAN_HINT in statements summary

[xhebox]

Bug Report

tidb/pkg/infoschema/tables.go

Line 1393 in d6db1e8

{name: stmtsummary.PlanHint, tp: mysql.TypeVarchar, size: 64, comment: "Sampled plan hint"},

It should be text, PLAN_HINT may be large. I encountered this when developing workload repository.

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4. What is your TiDB version? (Required)

master-09-13

[henrybw]

/assign

[tiancaiamao]

Do you mean size: 64 is too small for this column?
Maybe notice that enlarge value might cause chunk size too big and increase the Go GC burden.
Ref #28339

[xhebox]

Do you mean size: 64 is too small for this column? Maybe notice that enlarge value might cause chunk size too big and increase the Go GC burden. Ref #28339

Yeah, it is too small. There is no good workaround, since it will output much longer texts than the column definition. This works because that we don't check column types for internal mem table like this one.