test_plan_advice.c File Reference

#include "postgres.h"
#include "access/xact.h"
#include "fmgr.h"
#include "optimizer/optimizer.h"
#include "pg_plan_advice.h"
#include "utils/guc.h"

Include dependency graph for test_plan_advice.c:

Go to the source code of this file.

Functions
static char *	test_plan_advice_advisor (PlannerGlobal *glob, Query *parse, const char *query_string, int cursorOptions, ExplainState *es)
static DefElem *	find_defelem_by_defname (List *deflist, char *defname)
void	_PG_init (void)

Variables
	PG_MODULE_MAGIC
static bool	in_recursion = false

Function Documentation

_PG_init()

void _PG_init

(

void

)

Definition at line 42 of file test_plan_advice.c.

{
    void        (*add_advisor_fn) (pg_plan_advice_advisor_hook hook);
 
    /*
     * Ask pg_plan_advice to get advice strings from test_plan_advice_advisor
     */
    add_advisor_fn =
        load_external_function("pg_plan_advice", "pg_plan_advice_add_advisor",
                               true, NULL);
 
    (*add_advisor_fn) (test_plan_advice_advisor);
}

References fb(), load_external_function(), and test_plan_advice_advisor().

find_defelem_by_defname()

static DefElem * find_defelem_by_defname ( List *  deflist, char *  defname  )

static

Definition at line 134 of file test_plan_advice.c.

{
    foreach_node(DefElem, item, deflist)
    {
        if (strcmp(item->defname, defname) == 0)
            return item;
    }
 
    return NULL;
}

References fb(), and foreach_node.

Referenced by test_plan_advice_advisor().

test_plan_advice_advisor()

static char * test_plan_advice_advisor ( PlannerGlobal *  glob, Query *  parse, const char *  query_string, int  cursorOptions, ExplainState *  es  )

static

Definition at line 61 of file test_plan_advice.c.

{
    PlannedStmt *pstmt;
    int         save_nestlevel = 0;
    DefElem    *pgpa_item;
    DefElem    *advice_string_item;
 
    /*
     * Since this function is called from the planner and triggers planning,
     * we need a recursion guard.
     */
    if (in_recursion)
        return NULL;
 
    PG_TRY();
    {
        in_recursion = true;
 
        /*
         * Planning can trigger expression evaluation, which can result in
         * sending NOTICE messages or other output to the client. To avoid
         * that, we set client_min_messages = ERROR in the hopes of getting
         * the same output with and without this module.
         *
         * We also need to set pg_plan_advice.always_store_advice_details so
         * that pg_plan_advice will generate an advice string, since the whole
         * point of this function is to get access to that.
         */
        save_nestlevel = NewGUCNestLevel();
        set_config_option("client_min_messages", "error",
                          PGC_SUSET, PGC_S_SESSION,
                          GUC_ACTION_SAVE, true, 0, false);
        set_config_option("pg_plan_advice.always_store_advice_details", "true",
                          PGC_SUSET, PGC_S_SESSION,
                          GUC_ACTION_SAVE, true, 0, false);
 
        /*
         * Replan. We must copy the Query, because the planner modifies it.
         * (As noted elsewhere, that's unfortunate; perhaps it will be fixed
         * some day.)
         */
        pstmt = planner(copyObject(parse), query_string, cursorOptions,
                        glob->boundParams, es);
    }
    PG_FINALLY();
    {
        in_recursion = false;
    }
    PG_END_TRY();
 
    /* Roll back any GUC changes */
    if (save_nestlevel > 0)
        AtEOXact_GUC(false, save_nestlevel);
 
    /* Extract and return the advice string */
    pgpa_item = find_defelem_by_defname(pstmt->extension_state,
                                        "pg_plan_advice");
    if (pgpa_item == NULL)
        elog(ERROR, "extension state for pg_plan_advice not found");
    advice_string_item = find_defelem_by_defname((List *) pgpa_item->arg,
                                                 "advice_string");
    if (advice_string_item == NULL)
        elog(ERROR,
             "advice string for pg_plan_advice not found in extension state");
    return strVal(advice_string_item->arg);
}

References AtEOXact_GUC(), copyObject, elog, ERROR, PlannedStmt::extension_state, fb(), find_defelem_by_defname(), GUC_ACTION_SAVE, in_recursion, NewGUCNestLevel(), parse(), PG_END_TRY, PG_FINALLY, PG_TRY, PGC_S_SESSION, PGC_SUSET, planner(), set_config_option(), and strVal.

Referenced by _PG_init().

Variable Documentation

in_recursion

bool in_recursion = false

static

Definition at line 29 of file test_plan_advice.c.

Referenced by test_plan_advice_advisor().

PG_MODULE_MAGIC

PG_MODULE_MAGIC

Definition at line 27 of file test_plan_advice.c.