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/*-
* Copyright (c) 2008-2012 WiredTiger, Inc.
* All rights reserved.
*
* See the file LICENSE for redistribution information.
*/
#include "wt_internal.h"
/*
* __wt_bt_cache_force_write --
* Dirty the root page of the tree so it gets written.
*/
int
__wt_bt_cache_force_write(WT_SESSION_IMPL *session)
{
WT_BTREE *btree;
WT_PAGE *page;
btree = session->btree;
page = btree->root_page;
/* Dirty the root page to ensure a write. */
WT_RET(__wt_page_modify_init(session, page));
__wt_page_modify_set(page);
return (0);
}
/*
* __wt_bt_cache_flush --
* Write dirty pages from the cache, optionally discarding the file.
*/
int
__wt_bt_cache_flush(WT_SESSION_IMPL *session, WT_CKPT *ckptbase, int op)
{
WT_DECL_RET;
WT_BTREE *btree;
btree = session->btree;
/*
* Ask the eviction thread to flush any dirty pages, and optionally
* discard the file from the cache.
*
* Reconciliation is just another reader of the page, so it's probably
* possible to do this work in the current thread, rather than poking
* the eviction thread. The trick is for the sync thread to acquire
* hazard references on each dirty page, which would block the eviction
* thread from attempting to evict the pages.
*
* I'm not doing it for a few reasons: (1) I don't want sync to update
* the page's read-generation number, and eviction already knows how to
* do that, (2) I don't want more than a single sync running at a time,
* and calling eviction makes it work that way without additional work,
* (3) sync and eviction cannot operate on the same page at the same
* time and I'd rather they didn't operate in the same file at the same
* time, and using eviction makes it work that way without additional
* synchronization, (4) eventually we'll have async write I/O, and this
* approach results in one less page writer in the system, (5) the code
* already works that way. None of these problems can't be fixed, but
* I don't see a reason to change at this time, either.
*/
btree->ckpt = ckptbase;
ret = __wt_sync_file_serial(session, op);
btree->ckpt = NULL;
WT_RET(ret);
switch (op) {
case WT_SYNC:
break;
case WT_SYNC_DISCARD:
case WT_SYNC_DISCARD_NOWRITE:
/* If discarding the tree, the root page should be gone. */
WT_ASSERT(session, btree->root_page == NULL);
break;
}
return (0);
}
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