private static int InvalidatePageCacheAll()
{
var count = CachePages.CountTable(0);
CachePages.TruncateTable();
return(count);
}
protected override void OnPreRender(EventArgs e)
{
base.OnPreRender(e);
// Make sure this reflects changes
InvalidatePageCache();
var heading = PageCache.Politicians.GetPoliticianName(PoliticianKey);
if (heading != H1.InnerHtml)
{
H1.InnerHtml = heading;
UpdatePanelHeading.Update();
}
// This isn't available at Page_Load time
if (PageCachingSubHeadingWithHelp.FindTemplateControl("ViewIntroLink") is HtmlAnchor
viewIntroLink)
{
viewIntroLink.HRef = IntroPageUrl;
}
if (PageCachingSubHeadingWithHelp.FindTemplateControl("CacheExpirationMsg") is
HtmlGenericControl cacheExpirationMsg)
{
cacheExpirationMsg.InnerText =
CachePages.DisplayExpiration(MemCache.CacheExpiration);
}
// We handle post-update processing here so we only have to do it once per postback,
// not on each field.
if (_UpdateCount <= 0)
{
return;
}
Politicians.IncrementDataUpdatedCount(PoliticianKey);
}
private static void InvalidatePageCacheAll()
{
var count = CachePages.CountTable(0);
VotePage.LogInfo("LocalCacheInvalidation", "Begin InvalidatePageCacheAll:" +
count);
CachePages.TruncateTable();
VotePage.LogInfo("LocalCacheInvalidation", "End InvalidatePageCacheAll:" +
count);
}
private void SetAllCacheLabels()
{
var cacheRemovedAll = CacheControl.GetWhenCleared();
if (cacheRemovedAll != null)
{
LabelAllPagesLastRemoved.Text = cacheRemovedAll.Value.DbDateToShortDateTime(true);
}
LabelAllPagesCurrent.Text = CachePages.CountTable()
.ToString(CultureInfo.InvariantCulture);
}
private static void SaveLocalCacheBlob(string cacheType, string cacheKey,
DateTime dateStamp, byte[] cacheBlob)
{
// Save the rendered page in the local cache store.
// We ignore errors because parallel threads may try to create an
// identical cache entry
try
{
CachePages.Upsert(cacheType, cacheKey, dateStamp, cacheBlob);
}
catch
{
// ignored
}
}
private string GetCacheImage()
{
var cacheType = GetCacheType();
var cacheKey = GetCacheKey();
var expiration = MemCache.CacheExpiration;
var fuzzFactor = MemCache.CacheFuzzFactor;
// apply fuzz factor
var fuzz = Convert.ToInt32(Math.Round(expiration * (fuzzFactor / 100.0)));
if (fuzz != 0)
{
lock (Random)
expiration += Random.Next(-fuzz, fuzz);
}
var minDateStamp = DateTime.UtcNow - new TimeSpan(0, expiration, 0);
byte[] cacheBlob = null;
var localBlobTable = CachePages.GetUnexpiredPageImage(cacheType, cacheKey,
minDateStamp);
if (localBlobTable.Count == 1)
{
cacheBlob = localBlobTable[0].PageImage;
Interlocked.Increment(ref CurrentStatistics.PagesServedFromLocalCache);
}
else
{
var commonBlobTable =
DB.VoteCache.CachePages.GetUnexpiredPageImage(cacheType, cacheKey,
minDateStamp);
if (commonBlobTable.Count == 1)
{
cacheBlob = commonBlobTable[0].PageImage;
SaveLocalCacheBlob(cacheType, cacheKey, commonBlobTable[0].DateStamp,
cacheBlob);
Interlocked.Increment(ref CurrentStatistics.PagesServedFromCommonCache);
}
else
{
Interlocked.Increment(ref CurrentStatistics.PagesCreated);
}
}
if (_LastStatisticsSnapshot.SnapshotTime + StatisticsSnapshotInterval <
DateTime.UtcNow)
{
// May need to snapshot statistics, but make sure only one thread does it
if (Interlocked.Exchange(ref _SnapshottingStatistics, 1) == 0)
// it's our job
{
var previousSnapshot = _LastStatisticsSnapshot;
_LastStatisticsSnapshot = CurrentStatistics.Clone();
_LastStatisticsSnapshot.SnapshotTime = DateTime.UtcNow;
LogInfo("PageCaching",
$"Page caching from {previousSnapshot.SnapshotTime} to {_LastStatisticsSnapshot.SnapshotTime}:" +
$" {_LastStatisticsSnapshot.PagesServedFromMemoryCache - previousSnapshot.PagesServedFromMemoryCache} from memory cache," +
$" {_LastStatisticsSnapshot.PagesServedFromLocalCache - previousSnapshot.PagesServedFromLocalCache} from local cache," +
$" {_LastStatisticsSnapshot.PagesServedFromCommonCache - previousSnapshot.PagesServedFromCommonCache} from common cache," +
$" {_LastStatisticsSnapshot.PagesCreated - previousSnapshot.PagesCreated} created");
Interlocked.Exchange(ref _SnapshottingStatistics, 0);
}
}
return(cacheBlob == null ? null : Encoding.UTF8.GetString(cacheBlob));
}
