feat: projeciton not work

[fengys1996]

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[chatgpt-codex-connector]

💡 Codex Review

greptimedb/src/mito2/src/read/flat_projection.rs

Lines 117 to 118 in e0e67da

	let read_cols =
	build_read_columns(metadata, &projection_input.nested_paths, &read_column_ids)?;

Include predicate paths when pruning nested read columns

read_column_ids can contain extra columns required by pushed-down filters (from ScanRegion::build_read_column_ids), but this call builds ReadColumns using only projection_input.nested_paths. When a query projects one subfield (e.g. j.a) and filters on another subfield under the same root column (e.g. j.b), the reader will prune to only j.a, and later filter evaluation runs on incomplete data, which can drop matching rows or produce incorrect results. We need to merge filter-required nested paths (or disable nested pruning for predicate-referenced roots) before constructing ReadColumns.

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[fengys1996]

@codex review

[chatgpt-codex-connector]

💡 Codex Review

greptimedb/src/mito2/src/read/flat_projection.rs

Line 120 in 4fa9cbf

build_read_columns(metadata, &projection_input.nested_paths, &read_column_ids)?;

Merge predicate subfields into nested read paths

Building read columns from projection_input.nested_paths here can prune away nested fields that are only referenced by filters: scan_region::build_read_column_ids adds predicate-required root columns, but it does not add predicate subpaths, so a query like SELECT j.a ... WHERE j.b = ... can read only j.a and evaluate the predicate on incomplete data, yielding incorrect results. Either merge predicate nested paths before build_read_columns or disable nested pruning for predicate-referenced roots.

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