Change-Id: Iaa5361a09e1dc559fee8eb034c9c05bc999c776e
- * Generic base class for storage interfaces.
+ * Generic interface for lightweight expiring object stores.
*
* Provides convenient TTL constants.
*
*
* Provides convenient TTL constants.
*
const TTL_INDEFINITE = 0;
const TTL_INDEFINITE = 0;
- // Attribute and QoS constants; higher QOS values with the same prefix rank higher...
- // Medium attributes constants related to emulation or media type
+ // Emulation/fallback medium attribute (e.g. SQLBagOStuff)
const ATTR_EMULATION = 1;
const ATTR_EMULATION = 1;
+ // Quality of service constants for ATTR_EMULATION (higher means faster)
const QOS_EMULATION_SQL = 1;
const QOS_EMULATION_SQL = 1;
- // Medium attributes constants related to replica consistency
- const ATTR_SYNCWRITES = 2; // SYNC_WRITES flag support
+
+ // Replica synchronization/consistency attribute of medium when SYNC_WRITES is used
+ const ATTR_SYNCWRITES = 2;
+ // Quality of service constants for ATTR_SYNCWRITES (higher means more consistent)
const QOS_SYNCWRITES_NONE = 1; // replication only supports eventual consistency or less
const QOS_SYNCWRITES_BE = 2; // best effort synchronous with limited retries
const QOS_SYNCWRITES_QC = 3; // write quorum applied directly to state machines where R+W > N
const QOS_SYNCWRITES_SS = 4; // strict-serializable, nodes refuse reads if possible stale
const QOS_SYNCWRITES_NONE = 1; // replication only supports eventual consistency or less
const QOS_SYNCWRITES_BE = 2; // best effort synchronous with limited retries
const QOS_SYNCWRITES_QC = 3; // write quorum applied directly to state machines where R+W > N
const QOS_SYNCWRITES_SS = 4; // strict-serializable, nodes refuse reads if possible stale
// Generic "unknown" value that is useful for comparisons (e.g. always good enough)
const QOS_UNKNOWN = INF;
// Generic "unknown" value that is useful for comparisons (e.g. always good enough)
const QOS_UNKNOWN = INF;