170 lines
3.6 KiB
C
170 lines
3.6 KiB
C
/*-------------------------------------------------------------------------
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*
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* xid.c
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* POSTGRES transaction identifier and command identifier datatypes.
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*
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* Portions Copyright (c) 1996-2005, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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*
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* IDENTIFICATION
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* $PostgreSQL: pgsql/src/backend/utils/adt/xid.c,v 1.7 2004/12/31 22:01:22 pgsql Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#include "postgres.h"
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#include <limits.h>
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#include "access/xact.h"
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#include "libpq/pqformat.h"
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#include "utils/builtins.h"
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#define PG_GETARG_TRANSACTIONID(n) DatumGetTransactionId(PG_GETARG_DATUM(n))
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#define PG_RETURN_TRANSACTIONID(x) return TransactionIdGetDatum(x)
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#define PG_GETARG_COMMANDID(n) DatumGetCommandId(PG_GETARG_DATUM(n))
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#define PG_RETURN_COMMANDID(x) return CommandIdGetDatum(x)
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Datum
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xidin(PG_FUNCTION_ARGS)
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{
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char *str = PG_GETARG_CSTRING(0);
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PG_RETURN_TRANSACTIONID((TransactionId) strtoul(str, NULL, 0));
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}
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Datum
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xidout(PG_FUNCTION_ARGS)
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{
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TransactionId transactionId = PG_GETARG_TRANSACTIONID(0);
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/* maximum 32 bit unsigned integer representation takes 10 chars */
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char *str = palloc(11);
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snprintf(str, 11, "%lu", (unsigned long) transactionId);
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PG_RETURN_CSTRING(str);
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}
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/*
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* xidrecv - converts external binary format to xid
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*/
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Datum
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xidrecv(PG_FUNCTION_ARGS)
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{
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StringInfo buf = (StringInfo) PG_GETARG_POINTER(0);
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PG_RETURN_TRANSACTIONID((TransactionId) pq_getmsgint(buf, sizeof(TransactionId)));
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}
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/*
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* xidsend - converts xid to binary format
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*/
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Datum
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xidsend(PG_FUNCTION_ARGS)
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{
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TransactionId arg1 = PG_GETARG_TRANSACTIONID(0);
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StringInfoData buf;
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pq_begintypsend(&buf);
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pq_sendint(&buf, arg1, sizeof(arg1));
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PG_RETURN_BYTEA_P(pq_endtypsend(&buf));
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}
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/*
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* xideq - are two xids equal?
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*/
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Datum
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xideq(PG_FUNCTION_ARGS)
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{
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TransactionId xid1 = PG_GETARG_TRANSACTIONID(0);
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TransactionId xid2 = PG_GETARG_TRANSACTIONID(1);
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PG_RETURN_BOOL(TransactionIdEquals(xid1, xid2));
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}
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/*
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* xid_age - compute age of an XID (relative to current xact)
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*/
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Datum
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xid_age(PG_FUNCTION_ARGS)
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{
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TransactionId xid = PG_GETARG_TRANSACTIONID(0);
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TransactionId now = GetTopTransactionId();
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/* Permanent XIDs are always infinitely old */
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if (!TransactionIdIsNormal(xid))
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PG_RETURN_INT32(INT_MAX);
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PG_RETURN_INT32((int32) (now - xid));
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}
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/*****************************************************************************
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* COMMAND IDENTIFIER ROUTINES *
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*****************************************************************************/
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/*
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* cidin - converts CommandId to internal representation.
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*/
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Datum
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cidin(PG_FUNCTION_ARGS)
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{
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char *s = PG_GETARG_CSTRING(0);
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CommandId c;
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c = atoi(s);
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PG_RETURN_COMMANDID(c);
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}
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/*
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* cidout - converts a cid to external representation.
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*/
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Datum
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cidout(PG_FUNCTION_ARGS)
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{
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CommandId c = PG_GETARG_COMMANDID(0);
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char *result = (char *) palloc(16);
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snprintf(result, 16, "%u", (unsigned int) c);
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PG_RETURN_CSTRING(result);
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}
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/*
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* cidrecv - converts external binary format to cid
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*/
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Datum
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cidrecv(PG_FUNCTION_ARGS)
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{
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StringInfo buf = (StringInfo) PG_GETARG_POINTER(0);
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PG_RETURN_COMMANDID((CommandId) pq_getmsgint(buf, sizeof(CommandId)));
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}
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/*
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* cidsend - converts cid to binary format
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*/
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Datum
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cidsend(PG_FUNCTION_ARGS)
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{
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CommandId arg1 = PG_GETARG_COMMANDID(0);
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StringInfoData buf;
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pq_begintypsend(&buf);
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pq_sendint(&buf, arg1, sizeof(arg1));
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PG_RETURN_BYTEA_P(pq_endtypsend(&buf));
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}
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Datum
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cideq(PG_FUNCTION_ARGS)
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{
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CommandId arg1 = PG_GETARG_COMMANDID(0);
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CommandId arg2 = PG_GETARG_COMMANDID(1);
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PG_RETURN_BOOL(arg1 == arg2);
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}
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