/*
* __wt_log_wrlsn --
* Process written log slots and attempt to coalesce them if the LSNs
* are contiguous. The purpose of this function is to advance the
* write_lsn in LSN order after the buffer is written to the log file.
*/
int
__wt_log_wrlsn(WT_SESSION_IMPL *session)
{
WT_CONNECTION_IMPL *conn;
WT_DECL_RET;
WT_LOG *log;
WT_LOG_WRLSN_ENTRY written[WT_SLOT_POOL];
WT_LOGSLOT *coalescing, *slot;
WT_LSN save_lsn;
size_t written_i;
uint32_t i, save_i;
conn = S2C(session);
log = conn->log;
__wt_spin_lock(session, &log->log_writelsn_lock);
restart:
coalescing = NULL;
WT_INIT_LSN(&save_lsn);
written_i = 0;
i = 0;
/*
* Walk the array once saving any slots that are in the
* WT_LOG_SLOT_WRITTEN state.
*/
while (i < WT_SLOT_POOL) {
save_i = i;
slot = &log->slot_pool[i++];
/*
* XXX - During debugging I saw slot 0 become orphaned.
* I believe it is fixed, but check for now.
* This assertion should catch that.
*/
if (slot->slot_state == 0)
WT_ASSERT(session,
slot->slot_release_lsn.file >= log->write_lsn.file);
if (slot->slot_state != WT_LOG_SLOT_WRITTEN)
continue;
written[written_i].slot_index = save_i;
written[written_i++].lsn = slot->slot_release_lsn;
}
/*
* If we found any written slots process them. We sort them
* based on the release LSN, and then look for them in order.
*/
if (written_i > 0) {
WT_INSERTION_SORT(written, written_i,
WT_LOG_WRLSN_ENTRY, WT_WRLSN_ENTRY_CMP_LT);
/*
* We know the written array is sorted by LSN. Go
* through them either advancing write_lsn or coalesce
* contiguous ranges of written slots.
*/
for (i = 0; i < written_i; i++) {
slot = &log->slot_pool[written[i].slot_index];
/*
* The log server thread pushes out slots periodically.
* Sometimes they are empty slots. If we find an
* empty slot, where empty means the start and end LSN
* are the same, free it and continue.
*/
if (__wt_log_cmp(&slot->slot_start_lsn,
&slot->slot_release_lsn) == 0 &&
__wt_log_cmp(&slot->slot_start_lsn,
&slot->slot_end_lsn) == 0) {
__wt_log_slot_free(session, slot);
continue;
}
if (coalescing != NULL) {
/*
* If the write_lsn changed, we may be able to
* process slots. Try again.
*/
if (__wt_log_cmp(
&log->write_lsn, &save_lsn) != 0)
goto restart;
if (__wt_log_cmp(&coalescing->slot_end_lsn,
&written[i].lsn) != 0) {
coalescing = slot;
continue;
}
/*
* If we get here we have a slot to coalesce
* and free.
*/
coalescing->slot_last_offset =
slot->slot_last_offset;
coalescing->slot_end_lsn = slot->slot_end_lsn;
WT_STAT_FAST_CONN_INCR(
session, log_slot_coalesced);
/*
* Copy the flag for later closing.
*/
if (F_ISSET(slot, WT_SLOT_CLOSEFH))
F_SET(coalescing, WT_SLOT_CLOSEFH);
} else {
/*
* If this written slot is not the next LSN,
* try to start coalescing with later slots.
* A synchronous write may update write_lsn
* so save the last one we saw to check when
* coalescing slots.
*/
save_lsn = log->write_lsn;
if (__wt_log_cmp(
&log->write_lsn, &written[i].lsn) != 0) {
coalescing = slot;
continue;
}
/*
* If we get here we have a slot to process.
* Advance the LSN and process the slot.
*/
WT_ASSERT(session, __wt_log_cmp(&written[i].lsn,
&slot->slot_release_lsn) == 0);
if (slot->slot_start_lsn.offset !=
slot->slot_last_offset)
slot->slot_start_lsn.offset =
slot->slot_last_offset;
log->write_start_lsn = slot->slot_start_lsn;
log->write_lsn = slot->slot_end_lsn;
WT_ERR(__wt_cond_signal(
session, log->log_write_cond));
WT_STAT_FAST_CONN_INCR(session, log_write_lsn);
/*
* Signal the close thread if needed.
*/
if (F_ISSET(slot, WT_SLOT_CLOSEFH))
WT_ERR(__wt_cond_signal(
session, conn->log_file_cond));
}
__wt_log_slot_free(session, slot);
}
}
err: __wt_spin_unlock(session, &log->log_writelsn_lock);
return (ret);
}
/*
* __log_wrlsn_server --
* The log wrlsn server thread.
*/
static WT_THREAD_RET
__log_wrlsn_server(void *arg)
{
WT_CONNECTION_IMPL *conn;
WT_DECL_RET;
WT_LOG *log;
WT_LOG_WRLSN_ENTRY written[WT_SLOT_POOL];
WT_LOGSLOT *slot;
WT_SESSION_IMPL *session;
size_t written_i;
uint32_t i, save_i;
int yield;
session = arg;
conn = S2C(session);
log = conn->log;
yield = 0;
while (F_ISSET(conn, WT_CONN_LOG_SERVER_RUN)) {
/*
* No need to use the log_slot_lock because the slot pool
* is statically allocated and any slot in the
* WT_LOG_SLOT_WRITTEN state is exclusively ours for now.
*/
i = 0;
written_i = 0;
/*
* Walk the array once saving any slots that are in the
* WT_LOG_SLOT_WRITTEN state.
*/
while (i < WT_SLOT_POOL) {
save_i = i;
slot = &log->slot_pool[i++];
if (slot->slot_state != WT_LOG_SLOT_WRITTEN)
continue;
written[written_i].slot_index = save_i;
written[written_i++].lsn = slot->slot_release_lsn;
}
/*
* If we found any written slots process them. We sort them
* based on the release LSN, and then look for them in order.
*/
if (written_i > 0) {
yield = 0;
WT_INSERTION_SORT(written, written_i,
WT_LOG_WRLSN_ENTRY, WT_WRLSN_ENTRY_CMP_LT);
/*
* We know the written array is sorted by LSN. Go
* through them either advancing write_lsn or stop
* as soon as one is not in order.
*/
for (i = 0; i < written_i; i++) {
if (WT_LOG_CMP(&log->write_lsn,
&written[i].lsn) != 0)
break;
/*
* If we get here we have a slot to process.
* Advance the LSN and process the slot.
*/
slot = &log->slot_pool[written[i].slot_index];
WT_ASSERT(session, WT_LOG_CMP(&written[i].lsn,
&slot->slot_release_lsn) == 0);
log->write_start_lsn = slot->slot_start_lsn;
log->write_lsn = slot->slot_end_lsn;
WT_ERR(__wt_cond_signal(session,
log->log_write_cond));
WT_STAT_FAST_CONN_INCR(session, log_write_lsn);
/*
* Signal the close thread if needed.
*/
if (F_ISSET(slot, WT_SLOT_CLOSEFH))
WT_ERR(__wt_cond_signal(session,
conn->log_file_cond));
WT_ERR(__wt_log_slot_free(session, slot));
}
}
/*
* If we saw a later write, we always want to yield because
* we know something is in progress.
*/
if (yield++ < 1000)
__wt_yield();
else
/* Wait until the next event. */
WT_ERR(__wt_cond_wait(session,
conn->log_wrlsn_cond, 100000));
}
if (0)
err: __wt_err(session, ret, "log wrlsn server error");
return (WT_THREAD_RET_VALUE);
}
/*
* __snapsort --
* Sort an array of transaction IDs.
*/
static void
__snapsort(uint64_t *array, uint32_t size)
{
__snapsort_impl(array, 0, size - 1);
WT_INSERTION_SORT(array, size, uint64_t, WT_TXNID_LT);
}
/*
* __wt_log_wrlsn --
* Process written log slots and attempt to coalesce them if the LSNs
* are contiguous. Returns 1 if slots were freed, 0 if no slots were
* freed in the progress arg. Must be called with the log slot lock held.
*/
int
__wt_log_wrlsn(WT_SESSION_IMPL *session, uint32_t *free_i, int *yield)
{
WT_CONNECTION_IMPL *conn;
WT_LOG *log;
WT_LOG_WRLSN_ENTRY written[WT_SLOT_POOL];
WT_LOGSLOT *coalescing, *slot;
size_t written_i;
uint32_t i, save_i;
conn = S2C(session);
log = conn->log;
coalescing = NULL;
written_i = 0;
i = 0;
if (free_i != NULL)
*free_i = WT_SLOT_POOL;
/*
* Walk the array once saving any slots that are in the
* WT_LOG_SLOT_WRITTEN state.
*/
while (i < WT_SLOT_POOL) {
save_i = i;
slot = &log->slot_pool[i++];
if (free_i != NULL && *free_i == WT_SLOT_POOL &&
slot->slot_state == WT_LOG_SLOT_FREE)
*free_i = save_i;
if (slot->slot_state != WT_LOG_SLOT_WRITTEN)
continue;
written[written_i].slot_index = save_i;
written[written_i++].lsn = slot->slot_release_lsn;
}
/*
* If we found any written slots process them. We sort them
* based on the release LSN, and then look for them in order.
*/
if (written_i > 0) {
/*
* If wanted, reset the yield variable to indicate that we
* have found written slots.
*/
if (yield != NULL)
*yield = 0;
WT_INSERTION_SORT(written, written_i,
WT_LOG_WRLSN_ENTRY, WT_WRLSN_ENTRY_CMP_LT);
/*
* We know the written array is sorted by LSN. Go
* through them either advancing write_lsn or coalesce
* contiguous ranges of written slots.
*/
for (i = 0; i < written_i; i++) {
slot = &log->slot_pool[written[i].slot_index];
if (coalescing != NULL) {
if (WT_LOG_CMP(&coalescing->slot_end_lsn,
&written[i].lsn) != 0) {
coalescing = slot;
continue;
}
/*
* If we get here we have a slot to coalesce
* and free.
*/
coalescing->slot_end_lsn = slot->slot_end_lsn;
WT_STAT_FAST_CONN_INCR(
session, log_slot_coalesced);
/*
* Copy the flag for later closing.
*/
if (F_ISSET(slot, WT_SLOT_CLOSEFH))
F_SET(coalescing, WT_SLOT_CLOSEFH);
} else {
/*
* If this written slot is not the next LSN,
* try to start coalescing with later slots.
*/
if (WT_LOG_CMP(
&log->write_lsn, &written[i].lsn) != 0) {
coalescing = slot;
continue;
}
/*
* If we get here we have a slot to process.
* Advance the LSN and process the slot.
*/
WT_ASSERT(session, WT_LOG_CMP(&written[i].lsn,
&slot->slot_release_lsn) == 0);
log->write_start_lsn = slot->slot_start_lsn;
log->write_lsn = slot->slot_end_lsn;
WT_RET(__wt_cond_signal(
session, log->log_write_cond));
WT_STAT_FAST_CONN_INCR(session, log_write_lsn);
/*
* Signal the close thread if needed.
*/
if (F_ISSET(slot, WT_SLOT_CLOSEFH))
WT_RET(__wt_cond_signal(
session, conn->log_file_cond));
}
WT_RET(__wt_log_slot_free(session, slot));
if (free_i != NULL && *free_i == WT_SLOT_POOL &&
slot->slot_state == WT_LOG_SLOT_FREE)
*free_i = save_i;
}
}
return (0);
}
