Support column_list in CONTAINS

[jaspal007]

Description

Specifies two or more columns, separated by commas. column_list must be enclosed in parentheses. Unless language_term is specified, the language of all columns of column_list must be the same.

Issues

Previously Babelfish did not support syntax for multiple columns for simple terms in contains clause, as a result it was not configured to run the CONTAINS clause queries that required multiple columns.

• To fix this issue we have to change the way babelfish accepts the column list and then implement a way to rewrite those multiple columns into a way PostgreSQL can process.

syntax for multiple columns in TSQL

SELECT * FROM table_name WHERE CONTAINS((column_list), <predicate>)
GO

Now this syntax needs to be rewritten as a PostgreSQL query

SELECT * FROM table_name WHERE to_tsvector('configuration', column1||' '""column2||' '||...) @@
to_tsquery('configuration', <predicate>)

• Previously at the entry point of where the TSQL queries were written, the sys.replace_special_chars_fts function accepted only one column as an argument of type text which caused following issue

Changes to fix the issues

• Made the TSQL syntax identifiable in Babelfish, by adding the rule in gram-tsql-rule.y for CONTAINS clause.
• Fixed the entry point issue, by changing the sys.replace_special_chars_fts function declaration to accept variable number of columns as arguments by using Postgres keyword VARIADIC
• Changed the declaration of TsqlExpressionContains and makeToTSVectorFuncCall to accept the passed list of columns.

Task: BABEL-4239
Authored-by: Jaspal Singh [email protected]
Signed-off-by: Jaspal Singh [email protected]

Issue resolved

BABEL-4239
Engine side PR link: Support column_list in CONTAINS #521

Test Scenarios Covered

Use case based -

Boundary conditions -

Arbitrary inputs -

Negative test cases -

Minor version upgrade tests -

Major version upgrade tests -

Performance tests -

Tooling impact -

Client tests -

Check List

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