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/*-
* Copyright (c) 2014-present MongoDB, Inc.
* Copyright (c) 2008-2014 WiredTiger, Inc.
* All rights reserved.
*
* See the file LICENSE for redistribution information.
*/
/* Initialize the fields in a time window to their defaults. */
#define WT_TIME_WINDOW_INIT(tw) \
do { \
(tw)->durable_start_ts = WT_TS_NONE; \
(tw)->start_ts = WT_TS_NONE; \
(tw)->start_txn = WT_TXN_NONE; \
(tw)->durable_stop_ts = WT_TS_NONE; \
(tw)->stop_ts = WT_TS_MAX; \
(tw)->stop_txn = WT_TXN_MAX; \
(tw)->prepare = 0; \
} while (0)
/* Copy the values from one time window structure to another. */
#define WT_TIME_WINDOW_COPY(dest, source) (*(dest) = *(source))
/* Return true if the time window is equivalent to the default time window. */
#define WT_TIME_WINDOW_IS_EMPTY(tw) \
((tw)->durable_start_ts == WT_TS_NONE && (tw)->start_ts == WT_TS_NONE && \
(tw)->start_txn == WT_TXN_NONE && (tw)->durable_stop_ts == WT_TS_NONE && \
(tw)->stop_ts == WT_TS_MAX && (tw)->stop_txn == WT_TXN_MAX && (tw)->prepare == 0)
/* Check if the stop time window is set. */
#define WT_TIME_WINDOW_HAS_STOP(tw) ((tw)->stop_txn != WT_TXN_MAX || (tw)->stop_ts != WT_TS_MAX)
/* Return true if the time windows are the same. */
#define WT_TIME_WINDOWS_EQUAL(tw1, tw2) \
((tw1)->durable_start_ts == (tw2)->durable_start_ts && (tw1)->start_ts == (tw2)->start_ts && \
(tw1)->start_txn == (tw2)->start_txn && (tw1)->durable_stop_ts == (tw2)->durable_stop_ts && \
(tw1)->stop_ts == (tw2)->stop_ts && (tw1)->stop_txn == (tw2)->stop_txn && \
(tw1)->prepare == (tw2)->prepare)
/*
* Set the start values of a time window from those in an update structure. Durable timestamp can be
* 0 for prepared updates, in those cases use the prepared timestamp as durable timestamp.
*/
#define WT_TIME_WINDOW_SET_START(tw, upd) \
do { \
(tw)->durable_start_ts = (tw)->start_ts = (upd)->start_ts; \
if ((upd)->durable_ts != WT_TS_NONE) \
(tw)->durable_start_ts = (upd)->durable_ts; \
(tw)->start_txn = (upd)->txnid; \
} while (0)
/*
* Set the start values of a time window from those in an update structure. Durable timestamp can be
* 0 for prepared updates, in those cases use the prepared timestamp as durable timestamp.
*/
#define WT_TIME_WINDOW_SET_STOP(tw, upd) \
do { \
(tw)->durable_stop_ts = (tw)->stop_ts = (upd)->start_ts; \
if ((upd)->durable_ts != WT_TS_NONE) \
(tw)->durable_stop_ts = (upd)->durable_ts; \
(tw)->stop_txn = (upd)->txnid; \
} while (0)
/*
* Initialize the fields in an aggregated time window to their defaults. The aggregated durable
* timestamp values represent the maximum durable timestamp over set of timestamps. These aggregated
* max values are used for rollback to stable operation to find out whether the page has any
* timestamp updates more than stable timestamp.
*/
#define WT_TIME_AGGREGATE_INIT(ta) \
do { \
(ta)->newest_start_durable_ts = WT_TS_NONE; \
(ta)->newest_stop_durable_ts = WT_TS_NONE; \
(ta)->oldest_start_ts = WT_TS_NONE; \
(ta)->newest_txn = WT_TXN_NONE; \
(ta)->newest_stop_ts = WT_TS_MAX; \
(ta)->newest_stop_txn = WT_TXN_MAX; \
(ta)->prepare = 0; \
(ta)->init_merge = 0; \
} while (0)
/*
* Initialize the fields in an aggregated time window to maximum values, since this structure is
* generally populated by iterating over a set of timestamps and calculating max/min seen for each
* value, it's useful to be able to start with a negatively initialized structure. The aggregated
* durable timestamp values represent the maximum durable timestamp over set of timestamps. These
* aggregated max values are used for rollback to stable operation to find out whether the page has
* any timestamp updates more than stable timestamp.
*/
#define WT_TIME_AGGREGATE_INIT_MERGE(ta) \
do { \
(ta)->newest_start_durable_ts = WT_TS_NONE; \
(ta)->newest_stop_durable_ts = WT_TS_NONE; \
(ta)->oldest_start_ts = WT_TS_MAX; \
(ta)->newest_txn = WT_TXN_NONE; \
(ta)->newest_stop_ts = WT_TS_NONE; \
(ta)->newest_stop_txn = WT_TXN_NONE; \
(ta)->prepare = 0; \
(ta)->init_merge = 1; \
} while (0)
/* Return true if the time aggregate is equivalent to the initialized time aggregate. */
#define WT_TIME_AGGREGATE_IS_EMPTY(ta) \
((ta)->init_merge == 0 ? \
((ta)->newest_start_durable_ts == WT_TS_NONE && \
(ta)->newest_stop_durable_ts == WT_TS_NONE && (ta)->oldest_start_ts == WT_TS_NONE && \
(ta)->newest_txn == WT_TXN_NONE && (ta)->newest_stop_ts == WT_TS_MAX && \
(ta)->newest_stop_txn == WT_TXN_MAX && (ta)->prepare == 0) : \
((ta)->newest_start_durable_ts == WT_TS_NONE && \
(ta)->newest_stop_durable_ts == WT_TS_NONE && (ta)->oldest_start_ts == WT_TS_MAX && \
(ta)->newest_txn == WT_TXN_NONE && (ta)->newest_stop_ts == WT_TS_NONE && \
(ta)->newest_stop_txn == WT_TXN_NONE && (ta)->prepare == 0))
/* Copy the values from one time aggregate structure to another. */
#define WT_TIME_AGGREGATE_COPY(dest, source) (*(dest) = *(source))
/* Update the aggregated window to reflect for a new time window. */
#define WT_TIME_AGGREGATE_UPDATE(session, ta, tw) \
do { \
WT_ASSERT(session, (ta)->init_merge == 1); \
(ta)->newest_start_durable_ts = \
WT_MAX((tw)->durable_start_ts, (ta)->newest_start_durable_ts); \
(ta)->newest_stop_durable_ts = \
WT_MAX((tw)->durable_stop_ts, (ta)->newest_stop_durable_ts); \
(ta)->oldest_start_ts = WT_MIN((tw)->start_ts, (ta)->oldest_start_ts); \
(ta)->newest_txn = WT_MAX((tw)->start_txn, (ta)->newest_txn); \
/* \
* Aggregation of newest transaction is calculated from both start and \
* stop transactions. Consider only valid stop transactions. \
*/ \
if ((tw)->stop_txn != WT_TXN_MAX) \
(ta)->newest_txn = WT_MAX((tw)->stop_txn, (ta)->newest_txn); \
(ta)->newest_stop_ts = WT_MAX((tw)->stop_ts, (ta)->newest_stop_ts); \
(ta)->newest_stop_txn = WT_MAX((tw)->stop_txn, (ta)->newest_stop_txn); \
if ((tw)->prepare != 0) \
(ta)->prepare = 1; \
} while (0)
/* Merge an aggregated time window into another - choosing the most conservative value from each. */
#define WT_TIME_AGGREGATE_MERGE(session, dest, source) \
do { \
WT_ASSERT(session, (dest)->init_merge == 1); \
(dest)->newest_start_durable_ts = \
WT_MAX((dest)->newest_start_durable_ts, (source)->newest_start_durable_ts); \
(dest)->newest_stop_durable_ts = \
WT_MAX((dest)->newest_stop_durable_ts, (source)->newest_stop_durable_ts); \
(dest)->oldest_start_ts = WT_MIN((dest)->oldest_start_ts, (source)->oldest_start_ts); \
(dest)->newest_txn = WT_MAX((dest)->newest_txn, (source)->newest_txn); \
(dest)->newest_stop_ts = WT_MAX((dest)->newest_stop_ts, (source)->newest_stop_ts); \
(dest)->newest_stop_txn = WT_MAX((dest)->newest_stop_txn, (source)->newest_stop_txn); \
/* \
* Aggregation of newest transaction is calculated from both start and stop \
* transactions. Consider only valid stop transactions. \
*/ \
if ((dest)->newest_stop_txn != WT_TXN_MAX) \
(dest)->newest_txn = WT_MAX((dest)->newest_txn, (dest)->newest_stop_txn); \
if ((source)->prepare != 0) \
(dest)->prepare = 1; \
} while (0)
/*
* __wt_time_window_clear_obsolete --
* Where possible modify time window values to avoid writing obsolete values to the cell later.
*/
static inline void
__wt_time_window_clear_obsolete(
WT_SESSION_IMPL *session, WT_TIME_WINDOW *tw, uint64_t oldest_id, wt_timestamp_t oldest_ts)
{
/*
* In memory database don't need to avoid writing values to the cell. If we remove this check we
* create an extra update on the end of the chain later in reconciliation as we'll re-append the
* disk image value to the update chain.
*/
if (!tw->prepare && !F_ISSET(S2C(session), WT_CONN_IN_MEMORY)) {
if (tw->stop_txn == WT_TXN_MAX && tw->start_txn < oldest_id)
tw->start_txn = WT_TXN_NONE;
/* Avoid retrieving the pinned timestamp unless we need it. */
if (tw->stop_ts == WT_TS_MAX) {
/*
* The durable stop timestamp should be it's default value whenever the stop timestamp
* is.
*/
WT_ASSERT(session, tw->durable_stop_ts == WT_TS_NONE);
/*
* The durable start timestamp is always greater than or equal to the start timestamp,
* as such we must check it against the pinned timestamp and not the start timestamp.
*/
WT_ASSERT(session, tw->start_ts <= tw->durable_start_ts);
if (tw->durable_start_ts < oldest_ts)
tw->start_ts = tw->durable_start_ts = WT_TS_NONE;
}
}
}
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