Commit Graph

4 Commits

Author SHA1 Message Date
krad
d755c62f92 Persistent Read Cache (5) Volatile cache tier implementation
Summary:
This provides provides an implementation of PersistentCacheTier that is
specialized for RAM. This tier does not persist data though.

Why do we need this tier ?

This is ideal as tier 0. This tier can host data that is too hot.

Why can't we use Cache variants ?

Yes you can use them instead. This tier can potentially outperform BlockCache
in RAW mode by virtue of compression and compressed cache in block cache doesn't
seem very popular. Potentially this tier can be modified to under stand the
disadvantage of the tier below and retain data that the tier below is bad at
handling (for example index and bloom data that is huge in size)

Test Plan: Run unit tests added

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D57069
2016-06-07 11:10:44 -07:00
krad
62d5480984 Add persistent cache to Windows build system
Summary: Add hash table (under persistent cache) to CMake list

Test Plan: Run hash_test in windows and make check in Linux

Reviewers: sdong

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D59151
2016-06-02 17:48:25 -07:00
krad
4e7e41ba77 Disable lite build/testing for persistent read cache
Summary:
Persistent read cache isn't very applicable for lite builds. Wrapping
the code with #ifndef ROCKSDB_LITE .. #endif

Test Plan: Run unit, lite, lite_test

Reviewers: sdong

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D58563
2016-05-22 21:39:17 -07:00
krad
1f0142ce19 Persistent Read Cache (Part 2) Data structure for building persistent read cache index
Summary:
We expect the persistent read cache to perform at speeds upto 8 GB/s. In order
to accomplish that, we need build a index mechanism which operate in the order
of multiple millions per sec rate.

This patch provide the basic data structure to accomplish that:

(1) Hash table implementation with lock contention spread
    It is based on the StripedHashSet<T> implementation in
    The Art of multiprocessor programming by Maurice Henry & Nir Shavit
(2) LRU implementation
    Place holder algorithm for further optimizing
(3) Evictable Hash Table implementation
    Building block for building index data structure that evicts data like files
    etc

TODO:
(1) Figure if the sharded hash table and LRU can be used instead
(2) Figure if we need to support configurable eviction algorithm for
EvictableHashTable

Test Plan: Run unit tests

Subscribers: andrewkr, dhruba, leveldb

Differential Revision: https://reviews.facebook.net/D55785
2016-05-17 13:18:47 -07:00