Refactoring the filtering conditions in the current ExecNode from an expression tree to an array can simplify the process of adding runtime filters. It eliminates the need for complex merge operations and removes the requirement for the frontend to combine expressions into a single entity.
By representing the filtering conditions as an array, each condition can be treated individually, making it easier to add runtime filters without the need for complex merging logic. The array can store the individual conditions, and the runtime filter logic can iterate through the array to apply the filters as needed.
This refactoring simplifies the codebase, improves readability, and reduces the complexity associated with handling filtering conditions and adding runtime filters. It separates the conditions into discrete entities, enabling more straightforward manipulation and management within the execution node.
Co-authored-by: yiguolei <yiguolei@gmail.com>
Currently, exec node save exprcontext**, but the object is in object pool, the code is very unclear. we could just use exprcontext*.
Currently, there are some useless includes in the codebase. We can use a tool named include-what-you-use to optimize these includes. By using a strict include-what-you-use policy, we can get lots of benefits from it.
remove duplicate type definition in function context
remove unused method in function context
not need stale state in vexpr context because vexpr is stateless and function context saves state and they are cloned.
remove useless slot_size in all tuple or slot descriptor.
remove doris_udf namespace, it is useless.
remove some unused macro definitions.
init v_conjuncts in vscanner, not need write the same code in every scanner.
using unique ptr to manage function context since it could only belong to a single expr context.
Issue Number: close #xxx
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Co-authored-by: yiguolei <yiguolei@gmail.com>
Support new table value function `iceberg_meta("table" = "ctl.db.tbl", "query_type" = "snapshots")`
we can use the sql `select * from iceberg_meta("table" = "ctl.db.tbl", "query_type" = "snapshots")` to get snapshots info of a table. The other iceberg metadata will be supported later when needed.
One of the usage:
Before we use following sql to time travel:
`select * from ice_table FOR TIME AS OF "2022-10-10 11:11:11"`;
`select * from ice_table FOR VERSION AS OF "snapshot_id"`;
we can use the snapshots metadata to get the `committed time` or `snapshot_id`,
and then, we can use it as the time or version in time travel clause
