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75 lines
3.6 KiB
C++
75 lines
3.6 KiB
C++
/* -*- mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*- */
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// vim: ft=cpp:expandtab:ts=8:sw=4:softtabstop=4:
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#ident "$Id$"
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/*======
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This file is part of PerconaFT.
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Copyright (c) 2006, 2015, Percona and/or its affiliates. All rights reserved.
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PerconaFT is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License, version 2,
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as published by the Free Software Foundation.
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PerconaFT is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with PerconaFT. If not, see <http://www.gnu.org/licenses/>.
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----------------------------------------
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PerconaFT is free software: you can redistribute it and/or modify
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it under the terms of the GNU Affero General Public License, version 3,
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as published by the Free Software Foundation.
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PerconaFT is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Affero General Public License for more details.
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You should have received a copy of the GNU Affero General Public License
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along with PerconaFT. If not, see <http://www.gnu.org/licenses/>.
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======= */
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#ident "Copyright (c) 2006, 2015, Percona and/or its affiliates. All rights reserved."
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#pragma once
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#include "ft/ft-internal.h"
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// A leaf entry cursor (LE_CURSOR) is a special type of FT_CURSOR that visits all of the leaf entries in a tree
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// and returns the leaf entry to the caller. It maintains a copy of the key that it was last positioned over to
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// speed up key comparisions with a given key. For example, the hot indexing could use the _key_right_of_cursor
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// function to determine where a given key sits relative to the LE_CURSOR position.
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// When _next and _key_right_of_cursor functions are run on multiple threads, they must be protected by a lock. This
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// lock is assumed to exist outside of the LE_CURSOR.
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typedef struct le_cursor *LE_CURSOR;
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// Create a leaf cursor for a tree (ft_h) within a transaction (txn)
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// Success: returns 0, stores the LE_CURSOR in the le_cursor_result
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// Failure: returns a non-zero error number
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int toku_le_cursor_create(LE_CURSOR *le_cursor_result, FT_HANDLE ft_h, TOKUTXN txn);
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// Close and free the LE_CURSOR
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void toku_le_cursor_close(LE_CURSOR le_cursor);
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// Move to the next leaf entry under the LE_CURSOR
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// Success: returns zero, calls the getf callback with the getf_v parameter
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// Failure: returns a non-zero error number
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int toku_le_cursor_next(LE_CURSOR le_cursor, FT_GET_CALLBACK_FUNCTION getf, void *getf_v);
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// Return true if the key is to the right of the LE_CURSOR position. that is, current cursor key < given key
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// Otherwise returns false when the key is at or to the left of the LE_CURSOR position. that is, current cursor key >= given key
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// The LE_CURSOR position is intialized to -infinity. Any key comparision with -infinity returns true.
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// When the cursor runs off the right edge of the tree, the LE_CURSOR position is set to +infinity. Any key comparision with +infinity
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// returns false.
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bool toku_le_cursor_is_key_greater_or_equal(LE_CURSOR le_cursor, const DBT *key);
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// extracts position of le_cursor into estimate. Responsibility of caller to handle
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// thread safety. Caller (the indexer), does so by ensuring indexer lock is held
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void toku_le_cursor_update_estimate(LE_CURSOR le_cursor, DBT* estimate);
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