TLA  Line data    Source code

       1                 : /*-------------------------------------------------------------------------
       2                 :  *
       3                 :  * tablesample.c
       4                 :  *        Support functions for TABLESAMPLE feature
       5                 :  *
       6                 :  * Portions Copyright (c) 1996-2023, PostgreSQL Global Development Group
       7                 :  * Portions Copyright (c) 1994, Regents of the University of California
       8                 :  *
       9                 :  *
      10                 :  * IDENTIFICATION
      11                 :  *        src/backend/access/tablesample/tablesample.c
      12                 :  *
      13                 :  * -------------------------------------------------------------------------
      14                 :  */
      15                 : 
      16                 : #include "postgres.h"
      17                 : 
      18                 : #include "access/tsmapi.h"
      19                 : 
      20                 : 
      21                 : /*
      22                 :  * GetTsmRoutine --- get a TsmRoutine struct by invoking the handler.
      23                 :  *
      24                 :  * This is a convenience routine that's just meant to check for errors.
      25                 :  */
      26                 : TsmRoutine *
      27 CBC         512 : GetTsmRoutine(Oid tsmhandler)
      28                 : {
      29                 :     Datum       datum;
      30                 :     TsmRoutine *routine;
      31                 : 
      32             512 :     datum = OidFunctionCall1(tsmhandler, PointerGetDatum(NULL));
      33             512 :     routine = (TsmRoutine *) DatumGetPointer(datum);
      34                 : 
      35             512 :     if (routine == NULL || !IsA(routine, TsmRoutine))
      36 UBC           0 :         elog(ERROR, "tablesample handler function %u did not return a TsmRoutine struct",
      37                 :              tsmhandler);
      38                 : 
      39 CBC         512 :     return routine;
      40                 : }