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[update][Connector]oracle list database optimization

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### Check list * [x] When executing the "SELECT NAME FROM V $ DataBase" statement, there may be no authority, but you can return the current connected database

[connector-file-local][feature] add save mode function for localfile

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### Purpose of this pull request add save mode function for localfile ### Does this PR introduce _any_ user-facing change? NO ### How was this patch tested? add unit test...