hash_reclaim.c

/*-
 * See the file LICENSE for redistribution information.
 *
 * Copyright (c) 1996-2005
 *      Sleepycat Software.  All rights reserved.
 *
 * $Id: hash_reclaim.c,v 12.2 2005/06/16 20:22:53 bostic Exp $
 */

#include "db_config.h"

#ifndef NO_SYSTEM_INCLUDES
#include <sys/types.h>
#endif

#include "db_int.h"
#include "dbinc/db_page.h"
#include "dbinc/hash.h"

/*
 * __ham_reclaim --
 *      Reclaim the pages from a subdatabase and return them to the
 * parent free list.  For now, we link each freed page on the list
 * separately.  If people really store hash databases in subdatabases
 * and do a lot of creates and deletes, this is going to be a problem,
 * because hash needs chunks of contiguous storage.  We may eventually
 * need to go to a model where we maintain the free list with chunks of
 * contiguous pages as well.
 *
 * PUBLIC: int __ham_reclaim __P((DB *, DB_TXN *txn));
 */
int
__ham_reclaim(dbp, txn)
        DB *dbp;
        DB_TXN *txn;
{
        DBC *dbc;
        HASH_CURSOR *hcp;
        int ret;

        /* Open up a cursor that we'll use for traversing. */
        if ((ret = __db_cursor(dbp, txn, &dbc, 0)) != 0)
                return (ret);
        hcp = (HASH_CURSOR *)dbc->internal;

        if ((ret = __ham_get_meta(dbc)) != 0)
                goto err;

        if ((ret = __ham_traverse(dbc,
            DB_LOCK_WRITE, __db_reclaim_callback, dbc, 1)) != 0)
                goto err;
        if ((ret = __db_c_close(dbc)) != 0)
                goto err;
        if ((ret = __ham_release_meta(dbc)) != 0)
                goto err;
        return (0);

err:    if (hcp->hdr != NULL)
                (void)__ham_release_meta(dbc);
        (void)__db_c_close(dbc);
        return (ret);
}

/*
 * __ham_truncate --
 *      Reclaim the pages from a subdatabase and return them to the
 * parent free list.
 *
 * PUBLIC: int __ham_truncate __P((DBC *, u_int32_t *));
 */
int
__ham_truncate(dbc, countp)
        DBC *dbc;
        u_int32_t *countp;
{
        db_trunc_param trunc;
        int ret, t_ret;

        if ((ret = __ham_get_meta(dbc)) != 0)
                return (ret);

        trunc.count = 0;
        trunc.dbc = dbc;

        ret = __ham_traverse(dbc,
            DB_LOCK_WRITE, __db_truncate_callback, &trunc, 1);

        if ((t_ret = __ham_release_meta(dbc)) != 0 && ret == 0)
                ret = t_ret;

        if (countp != NULL)
                *countp = trunc.count;
        return (ret);
}

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