/// <summary>
/// Try to get the value from cache, with logging.
/// </summary>
private bool TryGetOrAdd(CachingQueryRunnerKey key, MessageContext msg, out CachingQueryRunnerValue result, Func <CachingQueryRunnerKey, CachingQueryRunnerValue> valueFactory)
{
bool foundValue;
foundValue = Cache.TryGetOrAdd(key, out result, valueFactory);
msg.Append(() => "CachingQueryRunner key:" + key);
if (foundValue)
{
var cacheValue = result;
msg.Append(() => "CachingQueryRunner cache hit");
msg.Append(() => $"Entry originally cached at {cacheValue.CacheTime}");
}
else
{
msg.Append(() => "CachingQueryRunner cache miss");
}
return(foundValue);
}
/// <summary>
/// Create cache keys
/// </summary>
/// <param name="query">The query</param>
/// <param name="settings">The query settings</param>
/// <param name="perUserKey">True if the key is for a specific user; or false if it is to be shared across users.</param>
/// <returns>The cache key</returns>
private CachingQueryRunnerKey CreateCacheKeyImpl(StructuredQuery query, QuerySettings settings, bool perUserKey)
{
// Get a user-set key
// (Users may share the same report SQL if they have the same set of read-rules)
UserRuleSet userRuleSet = null;
if (settings.RunAsUser != 0)
{
userRuleSet = UserRuleSetProvider.GetUserRuleSet(settings.RunAsUser, Permissions.Read);
if (userRuleSet == null)
{
throw new InvalidOperationException("Expected userRuleSet"); // Assert false
}
}
// Create cache key
// Cached with userId = -1 if the user
long userId = perUserKey ? settings.RunAsUser : ShareAcrossUsersCacheKey;
var key = new CachingQueryRunnerKey(query, settings, userRuleSet, userId);
return(key);
}
/// <summary>
/// Returns a suitable key for comparing query runs.
/// </summary>
/// <returns>A key, or null if the query should not be cached.</returns>
private CachingQueryRunnerKey CreateCacheKeyAndQuery(StructuredQuery query, QuerySettings settings, out QueryBuild builtQuery)
{
// Build the SQL for the query
// Note: unfortunately this may mutate the query, so keep a copy
StructuredQuery queryCopy = query.DeepCopy( );
builtQuery = BuildQueryImpl(queryCopy, settings);
// Check if query can even participate in cache
bool doNotCacheResult = builtQuery.SqlIsUncacheable ||
builtQuery.DataIsUncacheable ||
!CachingQueryRunnerKey.DoesRequestAllowForCaching(query, settings);
if (doNotCacheResult)
{
return(null);
}
// If we get to this point, then the cache is definitely participating
// Determine the cache key - either shared across users, or specific to the current user.
CachingQueryRunnerKey key = CreateCacheKeyImpl(query, settings, builtQuery.DataReliesOnCurrentUser);
return(key);
}