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Add +(pg_lsn,numeric) and -(pg_lsn,numeric) operators.

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By using these operators, the number of bytes can be added into and
subtracted from LSN.

Bump catalog version.

Author: Fujii Masao
Reviewed-by: Kyotaro Horiguchi, Michael Paquier, Asif Rehman
Discussion: https://postgr.es/m/ed9f7f74-e996-67f8-554a-52ebd3779b3b@oss.nttdata.com
This commit is contained in:
Fujii Masao
2020-06-30 23:55:07 +09:00
parent 324435eb14
commit 9bae7e4cde
10 changed files with 296 additions and 2 deletions
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69
src/backend/utils/adt/pg_lsn.c
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@@ -16,6 +16,7 @@
#include "funcapi.h"
#include "libpq/pqformat.h"
#include "utils/builtins.h"
#include "utils/numeric.h"
#include "utils/pg_lsn.h"
#define MAXPG_LSNLEN 17
@@ -248,3 +249,71 @@ pg_lsn_mi(PG_FUNCTION_ARGS)
return result;
}
/*
* Add the number of bytes to pg_lsn, giving a new pg_lsn.
* Must handle both positive and negative numbers of bytes.
*/
Datum
pg_lsn_pli(PG_FUNCTION_ARGS)
{
XLogRecPtr lsn = PG_GETARG_LSN(0);
Numeric nbytes = PG_GETARG_NUMERIC(1);
Datum num;
Datum res;
char buf[32];
if (numeric_is_nan(nbytes))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot add NaN to pg_lsn")));
/* Convert to numeric */
snprintf(buf, sizeof(buf), UINT64_FORMAT, lsn);
num = DirectFunctionCall3(numeric_in,
CStringGetDatum(buf),
ObjectIdGetDatum(0),
Int32GetDatum(-1));
/* Add two numerics */
res = DirectFunctionCall2(numeric_add,
NumericGetDatum(num),
NumericGetDatum(nbytes));
/* Convert to pg_lsn */
return DirectFunctionCall1(numeric_pg_lsn, res);
}
/*
* Subtract the number of bytes from pg_lsn, giving a new pg_lsn.
* Must handle both positive and negative numbers of bytes.
*/
Datum
pg_lsn_mii(PG_FUNCTION_ARGS)
{
XLogRecPtr lsn = PG_GETARG_LSN(0);
Numeric nbytes = PG_GETARG_NUMERIC(1);
Datum num;
Datum res;
char buf[32];
if (numeric_is_nan(nbytes))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot subtract NaN from pg_lsn")));
/* Convert to numeric */
snprintf(buf, sizeof(buf), UINT64_FORMAT, lsn);
num = DirectFunctionCall3(numeric_in,
CStringGetDatum(buf),
ObjectIdGetDatum(0),
Int32GetDatum(-1));
/* Subtract two numerics */
res = DirectFunctionCall2(numeric_sub,
NumericGetDatum(num),
NumericGetDatum(nbytes));
/* Convert to pg_lsn */
return DirectFunctionCall1(numeric_pg_lsn, res);
}