pgpa_planner.h

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/*-------------------------------------------------------------------------
 *
 * pgpa_planner.h
 *    planner integration for pg_plan_advice
 *
 * Copyright (c) 2016-2026, PostgreSQL Global Development Group
 *
 *    contrib/pg_plan_advice/pgpa_planner.h
 *
 *-------------------------------------------------------------------------
 */
#ifndef PGPA_PLANNER_H
#define PGPA_PLANNER_H
 
#include "pgpa_identifier.h"
 
extern void pgpa_planner_install_hooks(void);
 
/*
 * Per-PlannerInfo information that we gather during query planning.
 */
typedef struct pgpa_planner_info
{
    /* Plan name taken from the corresponding PlannerInfo; NULL at top level. */
    char       *plan_name;
 
    /*
     * If the corresponding PlannerInfo has an alternative_root, then this is
     * the plan name from that PlannerInfo; otherwise, it is the same as
     * plan_name.
     *
     * is_alternative_plan is set to true for every pgpa_planner_info that
     * shares an alternative_plan_name with at least one other, and to false
     * otherwise.
     */
    char       *alternative_plan_name;
    bool        is_alternative_plan;
 
    /* Relation identifiers computed for baserels at this query level. */
    pgpa_identifier *rid_array;
    int         rid_array_size;
 
    /*
     * If has_rtoffset is true, then rtoffset is the offset required to align
     * RTIs for this query level with RTIs from the final, flattened
     * rangetable. If has_rtoffset is false, then this subquery's range table
     * wasn't copied, or was only partially copied, into the final range
     * table. (Note that we can't determine the rtoffset values until the
     * final range table actually exists; before that time, has_rtoffset will
     * be false everywhere except at the top level.)
     */
    bool        has_rtoffset;
    Index       rtoffset;
 
    /*
     * List of Bitmapset objects. Each represents the relid set of a relation
     * that the planner considers making unique during semijoin planning.
     *
     * When generating advice, we should emit either SEMIJOIN_UNIQUE advice or
     * SEMIJOIN_NON_UNIQUE advice for each semijoin depending on whether we
     * chose to implement it as a semijoin or whether we instead chose to make
     * the nullable side unique and then perform an inner join. When the
     * make-unique strategy is not chosen, it's not easy to tell from the
     * final plan tree whether it was considered. That's awkward, because we
     * don't want to emit useless SEMIJOIN_NON_UNIQUE advice when there was no
     * decision to be made. This list lets the plan tree walker know in which
     * cases that approach was considered, so that it doesn't have to guess.
     */
    List       *sj_unique_rels;
} pgpa_planner_info;
 
/*
 * When set to a value greater than zero, indicates that advice should be
 * generated during query planning even in the absence of obvious reasons to
 * do so. See pg_plan_advice_request_advice_generation().
 */
extern int  pgpa_planner_generate_advice;
 
#endif