Support show and describe statement

[penghuo]

Related Issue:

#404

Description of changes

1. Add the support of SHOW and DESCRIBE.
2. Add orderedTable in the SymbotTable to keep the eleement ordered in the array. The reasons is when executing SELECT * FROM TABEL the * should be expanded following the order defined by TABLE schema.

Breaking Change

In the legacy engine, if the index has alias, the index name will be returned instead of the alias name. e.g.

PUT demo_index/alias/demo_alias

SHOW TABLES LIKE demo_alias

The demo_index will be returned as table name instead of demo_alias. In the new engine, we change to retrun the alias name, in the example, the demo_alias will be returned.

Todo

The current implementation doesn't existly follow the semantic definition of LIKE operator. Ideally, the operand of LIKE operator shoud be string literal to represent the match pattern. But the legacy engine use identifier in this case, e.g. SHOW TABLES LIKE %. For backward compability reason, we still support it now, but it will be deprecated soon.

To Reviewer

I briefly describe the changed files in each module.

1. core. add the orderedTable.
2. docs. no breaking change. the fields order chagned.
3. elasticsearch. the major change to implement show and describe.
4. integ-test. only one breaking change in MetaDataQueriesIT which has been reimplemented in AdminIT which only run with new engine.
5. protocol. remove the legecy type convert to type class.
6. sql. front end change for show/describe.

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov]

Codecov Report

Merging #907 (5b74a44) into develop (f16f21a) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@             Coverage Diff             @@
##             develop     #907    +/-   ##
===========================================
  Coverage      99.85%   99.86%            
- Complexity      2149     2190    +41     
===========================================
  Files            216      222     +6     
  Lines           4851     5028   +177     
  Branches         323      326     +3     
===========================================
+ Hits            4844     5021   +177     
  Misses             5        5            
  Partials           2        2            

Impacted Files	Coverage Δ	Complexity Δ
...orelasticsearch/sql/storage/TableScanOperator.java	100.00% <ø> (ø)	3.00 <0.00> (ø)
...forelasticsearch/sql/analysis/TypeEnvironment.java	100.00% <100.00%> (ø)	10.00 <1.00> (ø)
...elasticsearch/sql/analysis/symbol/SymbolTable.java	100.00% <100.00%> (ø)	17.00 <4.00> (+3.00)
...roforelasticsearch/sql/data/type/ExprCoreType.java	100.00% <100.00%> (ø)	10.00 <1.00> (+1.00)
...distroforelasticsearch/sql/data/type/ExprType.java	100.00% <100.00%> (ø)	7.00 <1.00> (+1.00)
...roforelasticsearch/sql/utils/SystemIndexUtils.java	100.00% <100.00%> (ø)	5.00 <5.00> (?)
.../elasticsearch/client/ElasticsearchNodeClient.java	100.00% <100.00%> (ø)	18.00 <2.00> (+2.00)
.../elasticsearch/client/ElasticsearchRestClient.java	100.00% <100.00%> (ø)	10.00 <2.00> (+2.00)
...elasticsearch/data/type/ElasticsearchDataType.java	100.00% <100.00%> (ø)	4.00 <1.00> (+1.00)
...csearch/executor/ElasticsearchExecutionEngine.java	100.00% <100.00%> (ø)	5.00 <0.00> (ø)
... and 18 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update f16f21a...5b74a44. Read the comment docs.

[dai-chen]

LGTM. Thanks! Could you check if any change needed to avoid this SHOW/DESCRIBE explain issue in new engine? #404

And could you also check if these 2 can be supported now?

1. #324: Filter by TABLE_CAT, TABLE_SCHEM and TABLE_TYPE
2. #238: Support for <catalog>.<table>

[penghuo]

LGTM. Thanks! Could you check if any change needed to avoid this SHOW/DESCRIBE explain issue in new engine? #404

And could you also check if these 2 can be supported now?

1. Extend support for SHOW query to apply filter on TABLE_CAT, TABLE_SCHEM and TABLE_TYPE #324: Filter by TABLE_CAT, TABLE_SCHEM and TABLE_TYPE
2. <catalog>.<table> syntax not supported #238: Support for <catalog>.<table>

• The SHOW/DESCRIBE explain throws exception #404 has been addressed.
• The Extend support for SHOW query to apply filter on TABLE_CAT, TABLE_SCHEM and TABLE_TYPE #324, <catalog>.<table> syntax not supported #238, we didn't support catalog now.