Implement the compatibility of explaintest with PostgreSQL

[hey-hoho]

Development Task

Description

ExplainTest is an independent test program. TiDB supports MySQL protocol natively. Now it needs to transform this part to be compatible with PostgreSQL protocol.

Task List

It mainly includes the following two parts:

• Client access protocol and connection mode

• Test case modification

This directory is in /cmd/explaintest.

The list of test cases is as follows:

• [ ] access_path_selection
• [ ] black_list
• [ ] explain_complex_stats
• [ ] explain_complex
• [ ] explain_easy_stats
• [ ] explain_easy
• [ ] explain_generate_column_substitute
• [ ] explain_indexmerge
• [ ] explain_join_stats
• [ ] explain_stats
• [ ] explain_union_scan
• [ ] explain-non-select-stmt
• [ ] explain
• [ ] generated_columns
• [ ] index_join
• [ ] partition_pruning
• [ ] select
• [ ] subquery
• [ ] topn_push_down
• [ ] topn_pushdown
• [ ] tpch
• [ ] window_function

Expected Results

All test cases can pass the test.