0.20.5: zip / tar.gz / issues

Release Notes:

Upgrade Notes:

• Upgrading from 0.19 requires a full cluster restart.

Breaking Changes:

• Shared Gateway has been deprecated (2458)
• Snappy compression has been deprecated (2459)
• Plugins Installer: Allow to download plugins from download.elasticsearch.org (#2507)

Enhancements:

• Id Cache: Allow to configure if ids should be reused (memory wise) or not, default to false (#2605)

Bug fixes:

• Cached script filter is not used in consecutive searches (#2651)
• Warmers do not load field data cache for sorting on new segments (#2649)
• possibly incorrect use of Lucene OneMerge.totalBytesSize (#2643)
• Bulk execution while a shard is replication might send erroneous version conflict failures for certain items (#2642)
• Index with no replicas might loose on going documents while relocating a shard (#2641)
• Filter cache stats may report incorrect values when index is recreated (#2609)
• NullPointerException (#2608)