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07140ee024
to bool's.
359 lines
7.5 KiB
C
359 lines
7.5 KiB
C
/*-------------------------------------------------------------------------
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*
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* dest.c--
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* support for various communication destinations - see lib/H/tcop/dest.h
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*
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* 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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* $Header: /cvsroot/pgsql/src/backend/tcop/dest.c,v 1.20 1998/05/19 18:05:47 momjian Exp $
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*
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*-------------------------------------------------------------------------
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*/
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/*
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* INTERFACE ROUTINES
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* BeginCommand - prepare destination for tuples of the given type
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* EndCommand - tell destination that no more tuples will arrive
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* NullCommand - tell dest that an empty query string was recognized
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* ReadyForQuery - tell dest that we are ready for a new query
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*
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* NOTES
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* These routines do the appropriate work before and after
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* tuples are returned by a query to keep the backend and the
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* "destination" portals synchronized.
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*
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*/
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#include <stdio.h> /* for sprintf() */
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#include <string.h>
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#include "postgres.h"
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#include "access/htup.h"
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#include "libpq/libpq.h"
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#include "access/printtup.h"
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#include "utils/portal.h"
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#include "utils/palloc.h"
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#include "executor/executor.h"
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#include "tcop/dest.h"
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#include "catalog/pg_type.h"
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#include "utils/mcxt.h"
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#include "commands/async.h"
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static char CommandInfo[32] = {0};
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/* ----------------
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* output functions
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* ----------------
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*/
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static void
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donothing(HeapTuple tuple, TupleDesc attrdesc)
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{
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}
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extern void spi_printtup(HeapTuple tuple, TupleDesc tupdesc);
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void (*
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DestToFunction(CommandDest dest)) (HeapTuple, TupleDesc)
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{
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switch (dest)
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{
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case RemoteInternal:
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return printtup_internal;
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break;
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case Remote:
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return printtup;
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break;
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case Local:
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return be_printtup;
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break;
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case Debug:
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return debugtup;
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break;
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case SPI:
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return spi_printtup;
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break;
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case None:
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default:
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return donothing;
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break;
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}
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/*
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* never gets here, but DECstation lint appears to be stupid...
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*/
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return donothing;
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}
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/* ----------------
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* EndCommand - tell destination that no more tuples will arrive
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* ----------------
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*/
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void
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EndCommand(char *commandTag, CommandDest dest)
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{
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char buf[64];
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switch (dest)
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{
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case RemoteInternal:
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case Remote:
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/* ----------------
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* tell the fe that the query is over
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* ----------------
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*/
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pq_putnchar("C", 1);
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sprintf(buf, "%s%s", commandTag, CommandInfo);
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CommandInfo[0] = 0;
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pq_putstr(buf);
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break;
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case Local:
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case Debug:
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case None:
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default:
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break;
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}
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}
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/*
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* These are necessary to sync communications between fe/be processes doing
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* COPY rel TO stdout
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*
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* or
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*
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* COPY rel FROM stdin
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*
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* NOTE: the message code letters are changed at protocol version 2.0
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* to eliminate possible confusion with data tuple messages.
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*/
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void
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SendCopyBegin(void)
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{
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if (PG_PROTOCOL_MAJOR(FrontendProtocol) >= 2)
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pq_putnchar("H", 1); /* new way */
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else
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pq_putnchar("B", 1); /* old way */
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}
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void
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ReceiveCopyBegin(void)
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{
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if (PG_PROTOCOL_MAJOR(FrontendProtocol) >= 2)
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pq_putnchar("G", 1); /* new way */
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else
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pq_putnchar("D", 1); /* old way */
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/* We *must* flush here to ensure FE knows it can send. */
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pq_flush();
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}
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/* ----------------
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* NullCommand - tell dest that an empty query string was recognized
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*
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* In FE/BE protocol version 1.0, this hack is necessary to support
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* libpq's crufty way of determining whether a multiple-command
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* query string is done. In protocol 2.0 it's probably not really
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* necessary to distinguish empty queries anymore, but we still do it
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* for backwards compatibility with 1.0.
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* ----------------
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*/
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void
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NullCommand(CommandDest dest)
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{
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switch (dest)
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{
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case RemoteInternal:
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case Remote:
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{
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/* ----------------
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* tell the fe that we saw an empty query string
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* ----------------
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*/
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pq_putstr("I");
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}
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break;
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case Local:
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case Debug:
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case None:
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default:
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break;
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}
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}
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/* ----------------
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* ReadyForQuery - tell dest that we are ready for a new query
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*
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* The ReadyForQuery message is sent in protocol versions 2.0 and up
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* so that the FE can tell when we are done processing a query string.
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*
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* Note that by flushing the stdio buffer here, we can avoid doing it
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* most other places and thus reduce the number of separate packets sent.
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* ----------------
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*/
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void
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ReadyForQuery(CommandDest dest)
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{
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switch (dest)
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{
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case RemoteInternal:
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case Remote:
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{
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if (PG_PROTOCOL_MAJOR(FrontendProtocol) >= 2)
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pq_putnchar("Z", 1);
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/* Flush output at end of cycle in any case. */
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pq_flush();
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}
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break;
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case Local:
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case Debug:
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case None:
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default:
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break;
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}
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}
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/* ----------------
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* BeginCommand - prepare destination for tuples of the given type
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* ----------------
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*/
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void
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BeginCommand(char *pname,
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int operation,
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TupleDesc tupdesc,
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bool isIntoRel,
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bool isIntoPortal,
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char *tag,
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CommandDest dest)
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{
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PortalEntry *entry;
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AttributeTupleForm *attrs = tupdesc->attrs;
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int natts = tupdesc->natts;
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int i;
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char *p;
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switch (dest)
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{
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case RemoteInternal:
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case Remote:
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/* ----------------
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* if this is a "retrieve portal" query, just return
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* because nothing needs to be sent to the fe.
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* ----------------
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*/
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CommandInfo[0] = 0;
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if (isIntoPortal)
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return;
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/* ----------------
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* if portal name not specified for remote query,
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* use the "blank" portal.
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* ----------------
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*/
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if (pname == NULL)
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pname = "blank";
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/* ----------------
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* send fe info on tuples we're about to send
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* ----------------
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*/
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pq_putnchar("P", 1);/* new portal.. */
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pq_putstr(pname); /* portal name */
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/* ----------------
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* if this is a retrieve, then we send back the tuple
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* descriptor of the tuples. "retrieve into" is an
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* exception because no tuples are returned in that case.
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* ----------------
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*/
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if (operation == CMD_SELECT && !isIntoRel)
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{
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pq_putnchar("T", 1); /* type info to follow.. */
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pq_putint(natts, 2); /* number of attributes in tuples */
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for (i = 0; i < natts; ++i)
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{
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pq_putstr(attrs[i]->attname.data); /* if 16 char name
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* oops.. */
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pq_putint((int) attrs[i]->atttypid, sizeof(attrs[i]->atttypid));
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pq_putint(attrs[i]->attlen, sizeof(attrs[i]->attlen));
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if (PG_PROTOCOL_MAJOR(FrontendProtocol) >= 2)
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pq_putint(attrs[i]->atttypmod, sizeof(attrs[i]->atttypmod));
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}
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}
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break;
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case Local:
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/* ----------------
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* prepare local portal buffer for query results
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* and setup result for PQexec()
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* ----------------
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*/
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entry = be_currentportal();
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if (pname != NULL)
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pbuf_setportalinfo(entry, pname);
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if (operation == CMD_SELECT && !isIntoRel)
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{
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be_typeinit(entry, tupdesc, natts);
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p = (char *) palloc(strlen(entry->name) + 2);
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p[0] = 'P';
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strcpy(p + 1, entry->name);
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}
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else
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{
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p = (char *) palloc(strlen(tag) + 2);
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p[0] = 'C';
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strcpy(p + 1, tag);
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}
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entry->result = p;
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break;
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case Debug:
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/* ----------------
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* show the return type of the tuples
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* ----------------
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*/
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if (pname == NULL)
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pname = "blank";
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showatts(pname, tupdesc);
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break;
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case None:
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default:
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break;
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}
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}
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void
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UpdateCommandInfo(int operation, Oid lastoid, uint32 tuples)
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{
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switch (operation)
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{
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case CMD_INSERT:
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if (tuples > 1)
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lastoid = InvalidOid;
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sprintf(CommandInfo, " %u %u", lastoid, tuples);
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break;
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case CMD_DELETE:
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case CMD_UPDATE:
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sprintf(CommandInfo, " %u", tuples);
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break;
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default:
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CommandInfo[0] = 0;
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}
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return;
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}
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