PostgreSQL: Parse optimizer hints in leading comments#2320
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iffyio merged 1 commit intoapache:mainfrom Apr 24, 2026
Merged
PostgreSQL: Parse optimizer hints in leading comments#2320iffyio merged 1 commit intoapache:mainfrom
iffyio merged 1 commit intoapache:mainfrom
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Enable comment-based optimizer hint parsing for the PostgreSQL dialect by overriding `supports_comment_optimizer_hint` to return `true`. PostgreSQL itself does not ship a built-in hint system, but the widely used `pg_hint_plan` extension (https://github.com/ossc-db/pg_hint_plan) introduces hints using the exact same `/*+ ... */` block-comment and `--+ ...` single-line-comment syntax already supported for MySQL and Oracle (apache#2162). Without this flag, parsing a `pg_hint_plan` statement such as: SELECT /*+ SeqScan(t) */ * FROM t; discards the hint as an ordinary comment, making it impossible for downstream tools (query rewriters, proxies, planners) built on `sqlparser-rs` to preserve or act on hints when targeting PostgreSQL. The parser side already handles this via `maybe_parse_optimizer_hint` across SELECT / INSERT / UPDATE / DELETE / MERGE, so no parser or AST changes are required — this is purely a dialect opt-in. The default remains `false`, so no other dialect is affected.
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LGTM! Thanks @altmannmarcelo!
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Enable comment-based optimizer hint parsing for the PostgreSQL dialect by overriding
supports_comment_optimizer_hintto returntrue.PostgreSQL itself does not ship a built-in hint system, but the widely used
pg_hint_planextension (https://github.com/ossc-db/pg_hint_plan) introduces hints using the exact same/*+ ... */block-comment and--+ ...single-line-comment syntax already supported for MySQL and Oracle (#2162). Without this flag, parsing apg_hint_planstatement such as:discards the hint as an ordinary comment, making it impossible for downstream tools (query rewriters, proxies, planners) built on
sqlparser-rsto preserve or act on hints when targeting PostgreSQL.The parser side already handles this via
maybe_parse_optimizer_hintacross SELECT / INSERT / UPDATE / DELETE / MERGE, so no parser or AST changes are required — this is purely a dialect opt-in. The default remainsfalse, so no other dialect is affected.