Mark table_constraints_internal() function as parallel safe and set current_db_id for parallel workers

[sumitj824]

Description

The INFORMATION_SCHEMA_TSQL.TABLE_CONSTRAINTS_INTERNAL() function was recently introduced but not marked as PARALLEL SAFE. This prevented the query optimizer from utilizing parallel plans in queries involving this function, leading to suboptimal performance for certain operations.

By marking the function as PARALLEL SAFE, we enable the use of parallel query execution plans, which can significantly improve performance for large datasets.

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After the above change, we were getting test failures related to INFORMATION_SCHEMA_TSQL.TABLE_CONSTRAINTS views in Enforced Parallel Query mode. On further investigation, we found that we were communicating the logical database name to parallel workers and setting the current_db_name using logical database name (Ref: #2262) but we missed to set current_db_id which gets used by function like sys.db_id(), sys.db_name() etc. and due to that queries involving join using these function was resulting empty rows.

This commit resolves the issue by setting the current_db_id along with current_db_name in set_cur_db_name_for_parallel_worker() function.

Signed-off-by: Sumit Jaiswal [email protected]

Issues Resolved

Task: BABEL-5427

Performance Testing

Query:

SELECT 
    tc.TABLE_SCHEMA, 
    tc.TABLE_NAME, 
    kcu.COLUMN_NAME, 
    c.DATA_TYPE 
FROM 
    INFORMATION_SCHEMA.TABLE_CONSTRAINTS tc 
JOIN 
    INFORMATION_SCHEMA.KEY_COLUMN_USAGE kcu 
    ON tc.CONSTRAINT_SCHEMA = kcu.CONSTRAINT_SCHEMA 
    AND tc.CONSTRAINT_NAME = kcu.CONSTRAINT_NAME 
JOIN 
    INFORMATION_SCHEMA.COLUMNS c 
    ON kcu.TABLE_SCHEMA = c.TABLE_SCHEMA 
    AND kcu.TABLE_NAME = c.TABLE_NAME 
    AND kcu.COLUMN_NAME = c.COLUMN_NAME 
WHERE 
    tc.CONSTRAINT_TYPE = 'PRIMARY KEY';

Before : 50187 ms
After: 47285 ms

Check List

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[coveralls]

Pull Request Test Coverage Report for Build 12512251302

Details

• 3 of 3 (100.0%) changed or added relevant lines in 1 file are covered.
• 3 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.003%) to 74.867%

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Files with Coverage Reduction	New Missed Lines	%
contrib/babelfishpg_tsql/src/session.c	1	97.44%
contrib/babelfishpg_tds/src/backend/tds/tdscomm.c	2	76.03%

Totals
Change from base Build 12502173129:	-0.003%
Covered Lines:	46706
Relevant Lines:	62385

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💛 - Coveralls