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CONFIG proxy.config.hostdb.size INT 120000
CONFIG proxy.config.hostdb.storage_size INT 45375488

• XML statistics can now be replaced with a Lua implementation instead.  See proxy.config.stats.enable_lua below.
• We have added a multi origin hierarchy to parent selection.
• Parent selection now also supports a failure mode, where you can retry requests against a different parent in some (configurable) cases.

Jira: TS-4207, TS-4115, TS-4287

New configuration options

• proxy.config.http.origin_max_connections_queue limits the number of requests to be queued when the proxy.config.http.origin_max_connections is reached.
• Two new timeouts are available for WebSockets: proxy.config.websocket.no_activity_timeout and proxy.config.websocket.active_timeout.
• The congestion control algorithm used is now configurable for both incoming, and outbound connections, via proxy.config.net.tcp_congestion_control_in and proxy.config.net.tcp_congestion_control_out.
• In preparation for the new Lua metrics module in v7.0.0, you can enable this feature in v6.2.x with proxy.config.stats.enable_lua.
• An experimental implementation of H2 streams priorities can be enabled with proxy.config.http2.stream_priority_enabled.
• We now provide better control over various H2 (HTTP/2) features, including proxy.config.http2.min_concurrent_streams_in, proxy.config.http2.max_active_streams_in and proxy.config.http2.active_timeout_in.

In addition, proxy.config.http.transaction_active_timeout_in is now also overridable.

Jira: TS-4341, TS-3922, TS-4064, TS-4099, TS-3535, TS-4087, TS-4162, 

TLS and HTTP/2 (aka H2)

 We continue to improve our TLS (HTTPS) features and support. Noteworthy in 6.2.x is:

• H2 is now much more feature rich, with a slew of bug fixes, configuration options, and performance optimizations. Try it out!
  • In particular, we now also have priority support for H2, but it's maybe not production ready for all use cases.
•  SPDY has been marked as deprecated, and will be removed for v7.0.0.

Jira: 

New plugins

• There's a new CPP API plugin for converting image formats to the webp format.
• There's a collapsed forwarding plugin in the experimental tree, this can help mitigate thundering herd issues in some cases.
• The beginning of an ACME (LetsEncrypt) plugin is in the source tree, but it needs more work to be complete. Volunteers are welcome!

Jira: TS-4095, TS-4243, TS-4320

Plugin Improvements

The following plugins have new features and improvements.

header_rewrite

• We now support variable expansion in the set-redirect operator.
• You can now do matching operators on the port.
• have a new operator for time based conditions, NOW().
• There's a new GeoIP operator, GEO().

Jira: TS-2642, TS-3639

cachekey

• We have added support for URI and URI path capture and replacements.
• The old cacheurl is now deprecated, in favor of our new, more complete cachekey plugin. Make sure to migrate to it if you use the old plugin!We do not need Boost.

Jira: TS-29554183, TS-3108, TS-3068

background_fetch

4356

gzip

• The gzip plugin can now function as a remap plugin, simplifying and strengthening configuration management. You can now selectively and efficiently enable gzip support easily per remap rule.
• The gzip plugin has also gone through some major rewrites, improving stability and performance
• The plugin behavior and activation can now be controlled per remap-rule.
• You an control the behavior based on content type.

Jira:   TS-26824147, TS-26834280

geoip_acl

We now support IPv6 for this plugin

Plugin APIs

The following additions were made to the plugin APIs:

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