StackOverflow2013

Note that there are some explanatory texts on larger screens.

plurals

PO
text
Body
copied!<p>The simplest approach is probably to compute a hash of the query, and insert the results into your dictionary using the hash as the key.</p> <p>If your queries are strings, you can probably just use the string.GetHashCode function to compute a simple hash on the string data. If your queries are Linq queries, .GetHashCode probably won't work unless Linq specifically overrides this method to compute a hash over the expression tree instead of the default object instance pointer. The default implementation of .GetHashCode simply returns a value that is derived from the object instance identity in memory, with no consideration of the data content of the object.</p> <p>If your queries are strings and are fairly uniform/consistent in construction, computing a simple string hash should be sufficient for reducing query traffic using the cache. If your queries are less consistent in structure (equivalent queries but with arguments in a different order, for example) you may need to build your own hash function that computes a hash on a canonicalized form of the input query to improve cache hit rates for queries that are logically equivalent but textually different.</p> <p>As your hash computation grows more computationally expensive, it will diminish the performance gains of using a cache. Make sure the query operation is sufficiently expensive to justify spending time computing hashes and consuming memory for the cache to produce a net savings in execution time. The query operation should be at least 2 or more orders of magnitude greater than the hash calc and cache management overhead. If your query operation is an out of process or cross-network call, your cache overhead will almost certainly be dwarfed by the cost of the query.</p>

Querying!

Guidance

An individual column

Larger individual text columns get their own page to allow for proper reading.

SQuiL has stopped working due to an internal error.

If you are curious you may find further information in the browser console, which is accessible through the devtools (F12).

Reload