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/*-------------------------------------------------------------------------
*
* pg_statistic.h
* definition of the system "statistic" relation (pg_statistic)
* along with the relation's initial contents.
*
*
* Portions Copyright (c) 1996-2001, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $Id: pg_statistic.h,v 1.10 2001/01/24 19:43:22 momjian Exp $
*
* NOTES
* the genbki.sh script reads this file and generates .bki
* information from the DATA() statements.
*
*-------------------------------------------------------------------------
*/
#ifndef PG_STATISTIC_H
#define PG_STATISTIC_H
/* ----------------
* postgres.h contains the system type definintions and the
* CATALOG(), BOOTSTRAP and DATA() sugar words so this file
* can be read by both genbki.sh and the C compiler.
* ----------------
*/
/* ----------------
* pg_statistic definition. cpp turns this into
* typedef struct FormData_pg_statistic
* ----------------
*/
CATALOG(pg_statistic)
{
/* These fields form the unique key for the entry: */
Oid starelid; /* relation containing attribute */
int2 staattnum; /* attribute (column) stats are for */
Oid staop; /* '<' comparison op used for lo/hi vals */
/*
* Note: the current VACUUM code will never produce more than one
* entry per column, but in theory there could be multiple entries if
* a datatype has more than one useful ordering operator. Also, the
* current code will not write an entry unless it found at least one
* non-NULL value in the column; so the remaining fields will never be
* NULL.
*/
/*
* These fields contain the stats about the column indicated by the
* key
*/
float4 stanullfrac; /* the fraction of the entries that are
* NULL */
float4 stacommonfrac; /* the fraction that are the most common
* val */
/*
* THE REST OF THESE ARE VARIABLE LENGTH FIELDS. They cannot be
* accessed as C struct entries; you have to use the full field access
* machinery (heap_getattr) for them.
*
* All three of these are text representations of data values of the
* column's data type. To re-create the actual Datum, do
* datatypein(textout(givenvalue)).
*/
text stacommonval; /* most common non-null value in column */
text staloval; /* smallest non-null value in column */
text stahival; /* largest non-null value in column */
} FormData_pg_statistic;
/* ----------------
* Form_pg_statistic corresponds to a pointer to a tuple with
* the format of pg_statistic relation.
* ----------------
*/
typedef FormData_pg_statistic *Form_pg_statistic;
/* ----------------
* compiler constants for pg_statistic
* ----------------
*/
#define Natts_pg_statistic 8
#define Anum_pg_statistic_starelid 1
#define Anum_pg_statistic_staattnum 2
#define Anum_pg_statistic_staop 3
#define Anum_pg_statistic_stanullfrac 4
#define Anum_pg_statistic_stacommonfrac 5
#define Anum_pg_statistic_stacommonval 6
#define Anum_pg_statistic_staloval 7
#define Anum_pg_statistic_stahival 8
#endif /* PG_STATISTIC_H */
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