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dbms:drastically improve performance by caching current time [#METR-13298]

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This commit is contained in:
Andrey Mironov 2015-02-27 16:08:00 +03:00
parent 3f34c733dd
commit 9d7fd21463
1 changed files with 6 additions and 8 deletions
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14
dbms/include/DB/Dictionaries/CacheDictionary.h
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@ -250,11 +250,6 @@ private:
return attr;
}
static bool hasTimeExpired(const std::chrono::system_clock::time_point & time_point)
{
return std::chrono::system_clock::now() >= time_point;
}
template <typename T>
void getItems(attribute_t & attribute, const PODArray<id_t> & ids, PODArray<T> & out) const
{
@ -264,6 +259,7 @@ private:
{
const Poco::ScopedReadRWLock read_lock{rw_lock};
const auto now = std::chrono::system_clock::now();
/// fetch up-to-date values, decide which ones require update
for (const auto i : ext::range(0, ids.size()))
{
@ -277,7 +273,7 @@ private:
const auto cell_idx = getCellIdx(id);
const auto & cell = cells[cell_idx];
if (cell.id != id || hasTimeExpired(cell.expires_at))
if (cell.id != id || cell.expires_at < now)
{
out[i] = std::get<T>(attribute.null_values);
outdated_ids[id].push_back(i);
@ -317,6 +313,7 @@ private:
{
const Poco::ScopedReadRWLock read_lock{rw_lock};
const auto now = std::chrono::system_clock::now();
/// fetch up-to-date values, discard on fail
for (const auto i : ext::range(0, ids.size()))
{
@ -331,7 +328,7 @@ private:
const auto cell_idx = getCellIdx(id);
const auto & cell = cells[cell_idx];
if (cell.id != id || hasTimeExpired(cell.expires_at))
if (cell.id != id || cell.expires_at < now)
{
found_outdated_values = true;
break;
@ -361,6 +358,7 @@ private:
{
const Poco::ScopedReadRWLock read_lock{rw_lock};
const auto now = std::chrono::system_clock::now();
for (const auto i : ext::range(0, ids.size()))
{
const auto id = ids[i];
@ -373,7 +371,7 @@ private:
const auto cell_idx = getCellIdx(id);
const auto & cell = cells[cell_idx];
if (cell.id != id || hasTimeExpired(cell.expires_at))
if (cell.id != id || cell.expires_at < now)
outdated_ids[id] += 1;
else
{