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/*-
* Copyright (c) 2014-2020 MongoDB, Inc.
* Copyright (c) 2008-2014 WiredTiger, Inc.
* All rights reserved.
*
* See the file LICENSE for redistribution information.
*/
/*
* __wt_time_window_init --
* Initialize the fields in a time window to their defaults.
*/
static inline void
__wt_time_window_init(WT_TIME_WINDOW *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;
}
/*
* __wt_time_window_init_max --
* Initialize the fields in a time window to values that force an override.
*/
static inline void
__wt_time_window_init_max(WT_TIME_WINDOW *tw)
{
tw->durable_start_ts = WT_TS_MAX;
tw->start_ts = WT_TS_MAX;
tw->start_txn = WT_TXN_MAX;
tw->durable_stop_ts = WT_TS_MAX;
tw->stop_ts = WT_TS_NONE;
tw->stop_txn = WT_TXN_NONE;
tw->prepare = 0;
}
/*
* __wt_time_window_copy --
* Copy the values from one time window structure to another.
*/
static inline void
__wt_time_window_copy(WT_TIME_WINDOW *dest, WT_TIME_WINDOW *source)
{
*dest = *source;
}
/*
* __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;
}
}
}
/*
* __wt_time_window_is_empty --
* Return true if the time window is equivalent to the default time window.
*/
static inline bool
__wt_time_window_is_empty(WT_TIME_WINDOW *tw)
{
return (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);
}
/*
* __wt_time_window_has_stop --
* Check if the stop time window is set.
*/
static inline bool
__wt_time_window_has_stop(WT_TIME_WINDOW *tw)
{
return (tw->stop_txn != WT_TXN_MAX || tw->stop_ts != WT_TS_MAX);
}
/*
* __wt_time_windows_equal --
* Return true if the time windows are the same.
*/
static inline bool
__wt_time_windows_equal(WT_TIME_WINDOW *tw1, WT_TIME_WINDOW *tw2)
{
return (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);
}
/*
* __wt_time_window_set_start --
* Set the start values of a time window from those in an update structure.
*/
static inline void
__wt_time_window_set_start(WT_TIME_WINDOW *tw, WT_UPDATE *upd)
{
/*
* Durable timestamp can be 0 for prepared updates, in those cases use the prepared timestamp as
* durable timestamp.
*/
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;
}
/*
* __wt_time_window_set_stop --
* Set the start values of a time window from those in an update structure.
*/
static inline void
__wt_time_window_set_stop(WT_TIME_WINDOW *tw, WT_UPDATE *upd)
{
/*
* Durable timestamp can be 0 for prepared updates, in those cases use the prepared timestamp as
* durable timestamp.
*/
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;
}
/*
* __wt_time_aggregate_init --
* Initialize the fields in an aggregated time window to their defaults.
*/
static inline void
__wt_time_aggregate_init(WT_TIME_AGGREGATE *ta)
{
/*
* 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.
*/
ta->newest_start_durable_ts = WT_TS_NONE;
ta->newest_stop_durable_ts = WT_TS_NONE;
ta->oldest_start_ts = WT_TS_NONE;
ta->oldest_start_txn = WT_TXN_NONE;
ta->newest_stop_ts = WT_TS_MAX;
ta->newest_stop_txn = WT_TXN_MAX;
ta->prepare = 0;
}
/*
* __wt_time_aggregate_init_max --
* 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.
*/
static inline void
__wt_time_aggregate_init_max(WT_TIME_AGGREGATE *ta)
{
/*
* 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.
*/
ta->newest_start_durable_ts = WT_TS_NONE;
ta->newest_stop_durable_ts = WT_TS_NONE;
ta->oldest_start_ts = WT_TS_MAX;
ta->oldest_start_txn = WT_TXN_MAX;
ta->newest_stop_ts = WT_TS_NONE;
ta->newest_stop_txn = WT_TXN_NONE;
ta->prepare = 0;
}
/*
* __wt_time_aggregate_is_empty --
* Return true if the time aggregate is equivalent to the default time aggregate.
*/
static inline bool
__wt_time_aggregate_is_empty(WT_TIME_AGGREGATE *ta)
{
return (ta->newest_start_durable_ts == WT_TS_NONE && ta->newest_stop_durable_ts == WT_TS_NONE &&
ta->oldest_start_ts == WT_TS_MAX && ta->oldest_start_txn == WT_TXN_MAX &&
ta->newest_stop_ts == WT_TS_NONE && ta->newest_stop_txn == WT_TXN_NONE && ta->prepare == 0);
}
/*
* __wt_time_aggregate_copy --
* Copy the values from one time aggregate structure to another.
*/
static inline void
__wt_time_aggregate_copy(WT_TIME_AGGREGATE *dest, WT_TIME_AGGREGATE *source)
{
*dest = *source;
}
/*
* __wt_time_aggregate_update --
* Update the aggregated window to reflect for a new time window.
*/
static inline void
__wt_time_aggregate_update(WT_TIME_AGGREGATE *ta, WT_TIME_WINDOW *tw)
{
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->oldest_start_txn = WT_MIN(tw->start_txn, ta->oldest_start_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;
}
/*
* __wt_time_aggregate_merge --
* Merge an aggregated time window into another - choosing the most conservative value from
* each.
*/
static inline void
__wt_time_aggregate_merge(WT_TIME_AGGREGATE *dest, WT_TIME_AGGREGATE *source)
{
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->oldest_start_txn = WT_MIN(dest->oldest_start_txn, source->oldest_start_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);
if (source->prepare != 0)
dest->prepare = 1;
}
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