private ColumnFamily getThroughCache(Integer cfId, QueryFilter filter)
{
assert isRowCacheEnabled()
: String.format("Row cache is not enabled on column family [" + getColumnFamilyName() + "]");
RowCacheKey key = new RowCacheKey(cfId, filter.key);
// attempt a sentinel-read-cache sequence. if a write invalidates our sentinel, we'll return our
// (now potentially obsolete) data, but won't cache it. see CASSANDRA-3862
IRowCacheEntry cached = CacheService.instance.rowCache.get(key);
if (cached != null)