From 7ef5f5fb324096c7822c922ad59fd7fdd76f57b1 Mon Sep 17 00:00:00 2001 From: Etsuro Fujita Date: Wed, 30 Aug 2023 17:45:00 +0900 Subject: [PATCH] Doc: Improve documentation for creating custom scan paths. This improves the documentation related to parallel query a little bit. Reviewed by Richard Guo. Discussion: https://postgr.es/m/CAPmGK159eJShAR4ek4Db8oHD4%2BZ18zwJkisEWkqRN-80BdDGFQ%40mail.gmail.com --- doc/src/sgml/custom-scan.sgml | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/doc/src/sgml/custom-scan.sgml b/doc/src/sgml/custom-scan.sgml index 836776b27bd..a200d502cdd 100644 --- a/doc/src/sgml/custom-scan.sgml +++ b/doc/src/sgml/custom-scan.sgml @@ -38,8 +38,8 @@ A custom scan provider will typically add paths for a base relation by setting the following hook, which is called after the core code has generated all the access paths it can for the relation (except for - Gather paths, which are made after this call so that they can use - partial paths added by the hook): + Gather and Gather Merge paths, which are made after this call so that + they can use partial paths added by the hook): typedef void (*set_rel_pathlist_hook_type) (PlannerInfo *root, RelOptInfo *rel, @@ -53,9 +53,10 @@ extern PGDLLIMPORT set_rel_pathlist_hook_type set_rel_pathlist_hook; Although this hook function can be used to examine, modify, or remove paths generated by the core system, a custom scan provider will typically confine itself to generating CustomPath objects and adding - them to rel using add_path. The custom scan - provider is responsible for initializing the CustomPath - object, which is declared like this: + them to rel using add_path, or + add_partial_path if they are partial paths. The + custom scan provider is responsible for initializing the + CustomPath object, which is declared like this: typedef struct CustomPath { -- 2.39.5