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Add a pg_lsn data type, to represent an LSN.

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Robert Haas and Michael Paquier
This commit is contained in:
Robert Haas
2014-02-19 08:35:23 -05:00
parent a222f7fda6
commit 7d03a83f4d
14 changed files with 391 additions and 3 deletions
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180
src/backend/utils/adt/pg_lsn.c Normal file
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/*-------------------------------------------------------------------------
*
* pg_lsn.c
* Internal PostgreSQL LSN operations
*
* Portions Copyright (c) 1996-2011, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* IDENTIFICATION
* src/backend/utils/adt/pg_lsn.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "funcapi.h"
#include "libpq/pqformat.h"
#include "utils/builtins.h"
#include "utils/pg_lsn.h"
#define MAXPG_LSNLEN 17
#define MAXPG_LSNCOMPONENT 8
/*----------------------------------------------------------
* Formatting and conversion routines.
*---------------------------------------------------------*/
Datum
pg_lsn_in(PG_FUNCTION_ARGS)
{
char *str = PG_GETARG_CSTRING(0);
int len1, len2;
uint32 id, off;
XLogRecPtr result;
/* Sanity check input format. */
len1 = strspn(str, "0123456789abcdefABCDEF");
if (len1 < 1 || len1 > MAXPG_LSNCOMPONENT || str[len1] != '/')
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("invalid input syntax for transaction log location: \"%s\"", str)));
len2 = strspn(str + len1 + 1, "0123456789abcdefABCDEF");
if (len2 < 1 || len2 > MAXPG_LSNCOMPONENT || str[len1 + 1 + len2] != '\0')
ereport(ERROR,
(errcode(ERRCODE_INVALID_TEXT_REPRESENTATION),
errmsg("invalid input syntax for transaction log location: \"%s\"", str)));
/* Decode result. */
id = (uint32) strtoul(str, NULL, 16);
off = (uint32) strtoul(str + len1 + 1, NULL, 16);
result = (XLogRecPtr) ((uint64) id << 32) | off;
PG_RETURN_PG_LSN(result);
}
Datum
pg_lsn_out(PG_FUNCTION_ARGS)
{
XLogRecPtr lsn = (XLogRecPtr) PG_GETARG_PG_LSN(0);
char buf[MAXPG_LSNLEN + 1];
char *result;
uint32 id, off;
/* Decode ID and offset */
id = (uint32) (lsn >> 32);
off = (uint32) lsn;
snprintf(buf, sizeof buf, "%X/%X", id, off);
result = pstrdup(buf);
PG_RETURN_CSTRING(result);
}
Datum
pg_lsn_recv(PG_FUNCTION_ARGS)
{
StringInfo buf = (StringInfo) PG_GETARG_POINTER(0);
XLogRecPtr result;
result = pq_getmsgint64(buf);
PG_RETURN_PG_LSN(result);
}
Datum
pg_lsn_send(PG_FUNCTION_ARGS)
{
XLogRecPtr lsn = (XLogRecPtr) PG_GETARG_PG_LSN(0);
StringInfoData buf;
pq_begintypsend(&buf);
pq_sendint64(&buf, lsn);
PG_RETURN_BYTEA_P(pq_endtypsend(&buf));
}
/*----------------------------------------------------------
* Operators for PostgreSQL LSNs
*---------------------------------------------------------*/
Datum
pg_lsn_eq(PG_FUNCTION_ARGS)
{
XLogRecPtr lsn1 = (XLogRecPtr) PG_GETARG_PG_LSN(0);
XLogRecPtr lsn2 = (XLogRecPtr) PG_GETARG_PG_LSN(1);
PG_RETURN_BOOL(lsn1 == lsn2);
}
Datum
pg_lsn_ne(PG_FUNCTION_ARGS)
{
XLogRecPtr lsn1 = (XLogRecPtr) PG_GETARG_PG_LSN(0);
XLogRecPtr lsn2 = (XLogRecPtr) PG_GETARG_PG_LSN(1);
PG_RETURN_BOOL(lsn1 != lsn2);
}
Datum
pg_lsn_lt(PG_FUNCTION_ARGS)
{
XLogRecPtr lsn1 = (XLogRecPtr) PG_GETARG_PG_LSN(0);
XLogRecPtr lsn2 = (XLogRecPtr) PG_GETARG_PG_LSN(1);
PG_RETURN_BOOL(lsn1 < lsn2);
}
Datum
pg_lsn_gt(PG_FUNCTION_ARGS)
{
XLogRecPtr lsn1 = (XLogRecPtr) PG_GETARG_PG_LSN(0);
XLogRecPtr lsn2 = (XLogRecPtr) PG_GETARG_PG_LSN(1);
PG_RETURN_BOOL(lsn1 > lsn2);
}
Datum
pg_lsn_le(PG_FUNCTION_ARGS)
{
XLogRecPtr lsn1 = (XLogRecPtr) PG_GETARG_PG_LSN(0);
XLogRecPtr lsn2 = (XLogRecPtr) PG_GETARG_PG_LSN(1);
PG_RETURN_BOOL(lsn1 <= lsn2);
}
Datum
pg_lsn_ge(PG_FUNCTION_ARGS)
{
XLogRecPtr lsn1 = (XLogRecPtr) PG_GETARG_PG_LSN(0);
XLogRecPtr lsn2 = (XLogRecPtr) PG_GETARG_PG_LSN(1);
PG_RETURN_BOOL(lsn1 >= lsn2);
}
/*----------------------------------------------------------
* Arithmetic operators on PostgreSQL LSNs.
*---------------------------------------------------------*/
Datum
pg_lsn_mi(PG_FUNCTION_ARGS)
{
XLogRecPtr lsn1 = (XLogRecPtr) PG_GETARG_PG_LSN(0);
XLogRecPtr lsn2 = (XLogRecPtr) PG_GETARG_PG_LSN(1);
char buf[256];
Datum result;
/* Negative results are not allowed. */
if (lsn1 < lsn2)
ereport(ERROR,
(errcode(ERRCODE_NUMERIC_VALUE_OUT_OF_RANGE),
errmsg("transaction log location out of range")));
/* Convert to numeric. */
snprintf(buf, sizeof buf, UINT64_FORMAT, lsn1 - lsn2);
result = DirectFunctionCall3(numeric_in,
CStringGetDatum(buf),
ObjectIdGetDatum(0),
Int32GetDatum(-1));
return result;
}