Invalidating query cache entries speed dating romania
The cleanup thread will not delete the directory as long as the lock file is held by the Hive instance.This mechanism would work as long as each Hive instance is responsible for its own results cache directory (which is the current plan), as opposed to having a cache that is shared among different Hive instances.Hive will need to check if the results for an incoming query are already saved in the results cache.
This cleanup works by creating a lockfile in the directory, and keeping the file open for the duration of the Hive instance.
Currently each Hive instance has its own separate results cache.
Originally the thinking was the query plan or AST would be part of the information saved in the cache, and might have been problematic to save and share between the different instances.
The methods that use the region parameter all supply a default Returns a filtered collection of elements that contains the descendant elements of every element and document in the source collection.
Only elements that have a matching XName are included in the collection.
So as long as the query string used for cache lookup can be derived from the rewritten AST (or the AST can be used during lookup), then query lookups should correctly distinguish cases where the query was modified from the original query text due to row/column filtering and masking.