test_copy_callbacks.c

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/*--------------------------------------------------------------------------
 *
 * test_copy_callbacks.c
 *      Code for testing COPY callbacks.
 *
 * Portions Copyright (c) 1996-2025, PostgreSQL Global Development Group
 * Portions Copyright (c) 1994, Regents of the University of California
 *
 * IDENTIFICATION
 *      src/test/modules/test_copy_callbacks/test_copy_callbacks.c
 *
 * -------------------------------------------------------------------------
 */
 
#include "postgres.h"
 
#include "access/table.h"
#include "commands/copy.h"
#include "fmgr.h"
#include "utils/rel.h"
 
PG_MODULE_MAGIC;
 
static void
to_cb(void *data, int len)
{
    ereport(NOTICE,
            (errmsg("COPY TO callback called with data \"%s\" and length %d",
                    (char *) data, len)));
}
 
PG_FUNCTION_INFO_V1(test_copy_to_callback);
Datum
test_copy_to_callback(PG_FUNCTION_ARGS)
{
    Relation    rel = table_open(PG_GETARG_OID(0), AccessShareLock);
    CopyToState cstate;
    int64       processed;
 
    cstate = BeginCopyTo(NULL, rel, NULL, RelationGetRelid(rel), NULL, false,
                         to_cb, NIL, NIL);
    processed = DoCopyTo(cstate);
    EndCopyTo(cstate);
 
    ereport(NOTICE, (errmsg("COPY TO callback has processed %lld rows",
                            (long long) processed)));
 
    table_close(rel, NoLock);
 
    PG_RETURN_VOID();
}