Support parsing ALTER STATISTICS in PostgreSQL

[everly-gif]

Ref #17848 .
Sub-issue of #14015

Changes proposed in this pull request:

• Proofread ALTER STATISTICS grammar
• Support parsing ALTER STATISTICS in PostgreSQL
• Add tests

✅ Builds locally

[codecov-commenter]

Codecov Report

Merging #19842 (b109bbb) into master (84f9266) will decrease coverage by 0.00%.
The diff coverage is 66.66%.

@@             Coverage Diff              @@
##             master   #19842      +/-   ##
============================================
- Coverage     60.12%   60.11%   -0.01%     
- Complexity     2409     2410       +1     
============================================
  Files          3852     3855       +3     
  Lines         54936    54935       -1     
  Branches       7706     7706              
============================================
- Hits          33031    33026       -5     
- Misses        19070    19075       +5     
+ Partials       2835     2834       -1     

Impacted Files	Coverage Δ
...common/statement/ddl/AlterStatisticsStatement.java	0.00% <0.00%> (ø)
...gresql/ddl/PostgreSQLAlterStatisticsStatement.java	0.00% <0.00%> (ø)
...atement/impl/PostgreSQLDDLStatementSQLVisitor.java	85.35% <100.00%> (+0.03%)	⬆️
...l/parser/core/database/visitor/SQLVisitorRule.java	100.00% <100.00%> (ø)
...eterized/jaxb/cases/domain/SQLParserTestCases.java	99.29% <100.00%> (+<0.01%)	⬆️
...tatement/ddl/AlterStatisticsStatementTestCase.java	100.00% <100.00%> (ø)
...handler/distsql/ral/hint/enums/HintSourceType.java	0.00% <0.00%> (-42.86%)	⬇️
.../datasource/pool/creator/DataSourceReflection.java	71.42% <0.00%> (-7.15%)	⬇️
...sistRepositoryConfigurationYamlSwapperFactory.java	100.00% <0.00%> (ø)
...here/infra/yaml/schema/pojo/YamlIndexMetaData.java
... and 15 more

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[strongduanmu]

Why remove ifExists?

[everly-gif]

it doesn't exsits in the PostgreSQL dialect here
https://www.postgresql.org/docs/current/sql-alterstatistics.html

[strongduanmu]

it doesn't exsits in the PostgreSQL dialect here https://www.postgresql.org/docs/current/sql-alterstatistics.html

Can you check this grammar in PostgreSQL source code?

[everly-gif]

you mean the postgres gram.y file right?

AlterStatsStmt:
			ALTER STATISTICS any_name SET STATISTICS SignedIconst
				{
					AlterStatsStmt *n = makeNode(AlterStatsStmt);

					n->defnames = $3;
					n->missing_ok = false;
					n->stxstattarget = $6;
					$$ = (Node *) n;
				}
			| ALTER STATISTICS IF_P EXISTS any_name SET STATISTICS SignedIconst
				{
					AlterStatsStmt *n = makeNode(AlterStatsStmt);

					n->defnames = $5;
					n->missing_ok = true;
					n->stxstattarget = $8;
					$$ = (Node *) n;
				}
			;

There if exists is supported.

[strongduanmu]

Yes, document is sometimes inaccurate, and source code can give us better guidance.

[everly-gif]

thank you for this tip! will keep this in my mind for my next PRs . Ill revert the changes for DDLStatement.g4

[strongduanmu]

@everly-gif Another perfect pr. 👍