executor: use sys session to build view for info_schema.columns
retrieval (#33946)
#34252
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cherry-pick #33946 to release-5.3
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# In tidb repo: git pr https://github.com/pingcap/tidb/pull/34252
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What problem does this PR solve?
Issue Number: close #32459
Problem Summary:
From the panic cases related to
information_schema.columns
we encountered recently, the stack is like:All of these stacks have the common function:
tryFillViewColumnType
andfetchBuildSideRows
.tryFillViewColumnType
is used to extract the field type of a view ininformation_schema.columns
.fetchBuildSideRows
is used by HashJoinExec to get the build side of the result. It is run concurrently withfetchProbeSideChunks
to speed up the query.As explained in #32618, the root cause is: the goroutines created by
HashJoinExec
concurrently accessed a field in the same session.What is changed and how it works?
This PR uses a system session to
tryFillViewColumnType
, preventing the same session is accessed concurrently.Check List
Tests
Side effects
Documentation
Release note
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