database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-07 00:36:50 +03:00
Code Activity

Reimplement NUMERIC datatype using base-10000 arithmetic; also improve

Browse Source 
some of the algorithms for higher functions.  I see about a factor of ten
speedup on the 'numeric' regression test, but it's unlikely that that test
is representative of real-world applications.
initdb forced due to change of on-disk representation for NUMERIC.
This commit is contained in:
Tom Lane
2003-03-21 01:58:05 +00:00
parent 5ae424529b
commit d72f6c7503
6 changed files with 1590 additions and 960 deletions
Download Patch File Download Diff File Expand all files Collapse all files

38
src/include/utils/numeric.h
View File

@ -1,15 +1,16 @@
/* ----------
/*-------------------------------------------------------------------------
*
* numeric.h
* Definitions for the exact numeric data type of Postgres
*
* Definitions for the exact numeric data type of Postgres
* Original coding 1998, Jan Wieck. Heavily revised 2003, Tom Lane.
*
* 1998 Jan Wieck
* Copyright (c) 1998-2003, PostgreSQL Global Development Group
*
* $Id: numeric.h,v 1.16 2002/10/02 19:21:26 tgl Exp $
* $Id: numeric.h,v 1.17 2003/03/21 01:58:05 tgl Exp $
*
* ----------
*-------------------------------------------------------------------------
*/
#ifndef _PG_NUMERIC_H_
#define _PG_NUMERIC_H_
@ -34,12 +35,6 @@
*/
#define NUMERIC_MIN_SIG_DIGITS 16
/*
* Standard number of extra digits carried internally while doing
* inexact calculations.
*/
#define NUMERIC_EXTRA_DIGITS 4
/*
* Sign values and macros to deal with packing/unpacking n_sign_dscale
@ -51,30 +46,29 @@
#define NUMERIC_DSCALE_MASK 0x3FFF
#define NUMERIC_SIGN(n) ((n)->n_sign_dscale & NUMERIC_SIGN_MASK)
#define NUMERIC_DSCALE(n) ((n)->n_sign_dscale & NUMERIC_DSCALE_MASK)
#define NUMERIC_IS_NAN(n) (NUMERIC_SIGN(n) != NUMERIC_POS && \
NUMERIC_SIGN(n) != NUMERIC_NEG)
#define NUMERIC_IS_NAN(n) (NUMERIC_SIGN(n) != NUMERIC_POS && \
NUMERIC_SIGN(n) != NUMERIC_NEG)
/*
* The Numeric data type stored in the database
*
* NOTE: by convention, values in the packed form have been stripped of
* all leading and trailing zeroes (except there will be a trailing zero
* in the last byte, if the number of digits is odd). In particular,
* if the value is zero, there will be no digits at all! The weight is
* arbitrary in that case, but we normally set it to zero.
* all leading and trailing zero digits (where a "digit" is of base NBASE).
* In particular, if the value is zero, there will be no digits at all!
* The weight is arbitrary in that case, but we normally set it to zero.
*/
typedef struct NumericData
{
int32 varlen; /* Variable size */
int32 varlen; /* Variable size (std varlena header) */
int16 n_weight; /* Weight of 1st digit */
uint16 n_rscale; /* Result scale */
uint16 n_sign_dscale; /* Sign + display scale */
unsigned char n_data[1]; /* Digit data (2 decimal digits/byte) */
char n_data[1]; /* Digits (really array of NumericDigit) */
} NumericData;
typedef NumericData *Numeric;
#define NUMERIC_HDRSZ (sizeof(int32) + sizeof(uint16) * 3)
#define NUMERIC_HDRSZ (sizeof(int32) + sizeof(int16) + sizeof(uint16))
/*