[bug] replace mmdb database sometimes results in crash

[111andre111]

For all general issues, please provide the following details for fast resolution:
today there is a need of restarting logstash for reloading the Maxmind geoip databases
Referring to this comment:
#63 (comment)
I would like to raise this now as it would be good to have the possibility to reload the database without restarting logstash, and with that you can update the database and logstash would be quite immediately aware of it.

From implementation perspective there are existing mechanisms already that can be taken as a blueprint from the translate plugin:
https://github.com/logstash-plugins/logstash-filter-translate/blob/5cbb57c9a34865856de9ead577c19d42c4b75ade/lib/logstash/filters/dictionary/file.rb#L119
reload_dictionary
https://github.com/logstash-plugins/logstash-filter-translate/blob/5cbb57c9a34865856de9ead577c19d42c4b75ade/lib/logstash/filters/dictionary/file.rb#L128
needs_refresh
and then offer the 2 configurable settings
refresh_interval
and if needed refresh_behaviour
www.elastic.co/guide/en/logstash/current/plugins-filters-translate.html

[111andre111]

I think I have to revise this one as I did a short test with two custom geoip databases that had a changing field content and during using copying the mmdb and a running logstash the values changed quite immediately, so logstash is getting aware of it. Sorry for the confusion.

[111andre111]

When I replace the mmdb under the hood of logstash it seems that it sometimes crashes logstash which should even not happen, so let me reopen this one again.

warning: thread "[main]>worker0" terminated with exception (report_on_exception is true):
java.lang.InternalError: a fault occurred in a recent unsafe memory access operation in compiled Java code
	at com.maxmind.db.Reader.resolveDataPointer(com/maxmind/db/Reader.java:242)
	at com.maxmind.db.Reader.get(com/maxmind/db/Reader.java:150)
	at com.maxmind.geoip2.DatabaseReader.get(com/maxmind/geoip2/DatabaseReader.java:151)
	at com.maxmind.geoip2.DatabaseReader.city(com/maxmind/geoip2/DatabaseReader.java:202)
	at org.logstash.filters.GeoIPFilter.retrieveCityGeoData(org/logstash/filters/GeoIPFilter.java:191)
	at org.logstash.filters.GeoIPFilter.handleEvent(org/logstash/filters/GeoIPFilter.java:144)
	at jdk.internal.reflect.GeneratedMethodAccessor8.invoke(jdk/internal/reflect/GeneratedMethodAccessor8)
	at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(jdk/internal/reflect/DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(java/lang/reflect/Method.java:564)
	at org.jruby.javasupport.JavaMethod.invokeDirectWithExceptionHandling(org/jruby/javasupport/JavaMethod.java:456)
	at org.jruby.javasupport.JavaMethod.invokeDirect(org/jruby/javasupport/JavaMethod.java:317)
	at Users.andreletterer.Downloads.tools.logstash_minus_7_dot_7_dot_0.vendor.bundle.jruby.$2_dot_5_dot_0.gems.logstash_minus_filter_minus_geoip_minus_6_dot_0_dot_3_minus_java.lib.logstash.filters.geoip.filter(Users/andreletterer/Downloads/tools/logstash_minus_7_dot_7_dot_0/vendor/bundle/jruby/$2_dot_5_dot_0/gems/logstash_minus_filter_minus_geoip_minus_6_dot_0_dot_3_minus_java/lib/logstash/filters//Users/andreletterer/Downloads/tools/logstash-7.7.0/vendor/bundle/jruby/2.5.0/gems/logstash-filter-geoip-6.0.3-java/lib/logstash/filters/geoip.rb:109)
	at Users.andreletterer.Downloads.tools.logstash_minus_7_dot_7_dot_0.logstash_minus_core.lib.logstash.filters.base.do_filter(Users/andreletterer/Downloads/tools/logstash_minus_7_dot_7_dot_0/logstash_minus_core/lib/logstash/filters//Users/andreletterer/Downloads/tools/logstash-7.7.0/logstash-core/lib/logstash/filters/base.rb:159)
	at Users.andreletterer.Downloads.tools.logstash_minus_7_dot_7_dot_0.logstash_minus_core.lib.logstash.filters.base.multi_filter(Users/andreletterer/Downloads/tools/logstash_minus_7_dot_7_dot_0/logstash_minus_core/lib/logstash/filters//Users/andreletterer/Downloads/tools/logstash-7.7.0/logstash-core/lib/logstash/filters/base.rb:178)
	at org.jruby.RubyArray.each(org/jruby/RubyArray.java:1809)
	at Users.andreletterer.Downloads.tools.logstash_minus_7_dot_7_dot_0.logstash_minus_core.lib.logstash.filters.base.multi_filter(Users/andreletterer/Downloads/tools/logstash_minus_7_dot_7_dot_0/logstash_minus_core/lib/logstash/filters//Users/andreletterer/Downloads/tools/logstash-7.7.0/logstash-core/lib/logstash/filters/base.rb:175)
	at org.logstash.config.ir.compiler.FilterDelegatorExt.doMultiFilter(org/logstash/config/ir/compiler/FilterDelegatorExt.java:127)
	at org.logstash.config.ir.compiler.AbstractFilterDelegatorExt.multi_filter(org/logstash/config/ir/compiler/AbstractFilterDelegatorExt.java:134)
	at org.logstash.generated.CompiledDataset1.compute(org/logstash/generated/CompiledDataset1)
	at org.logstash.generated.CompiledDataset2.compute(org/logstash/generated/CompiledDataset2)
	at org.logstash.config.ir.CompiledPipeline$CompiledOrderedExecution.compute(org/logstash/config/ir/CompiledPipeline.java:334)
	at org.logstash.config.ir.CompiledPipeline$CompiledOrderedExecution.compute(org/logstash/config/ir/CompiledPipeline.java:318)
	at org.logstash.execution.WorkerLoop.run(org/logstash/execution/WorkerLoop.java:82)
	at jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
	at jdk.internal.reflect.NativeMethodAccessorImpl.invoke(jdk/internal/reflect/NativeMethodAccessorImpl.java:62)
	at jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(jdk/internal/reflect/DelegatingMethodAccessorImpl.java:43)
	at java.lang.reflect.Method.invoke(java/lang/reflect/Method.java:564)
	at org.jruby.javasupport.JavaMethod.invokeDirectWithExceptionHandling(org/jruby/javasupport/JavaMethod.java:426)
	at org.jruby.javasupport.JavaMethod.invokeDirect(org/jruby/javasupport/JavaMethod.java:293)
	at Users.andreletterer.Downloads.tools.logstash_minus_7_dot_7_dot_0.logstash_minus_core.lib.logstash.java_pipeline.start_workers(Users/andreletterer/Downloads/tools/logstash_minus_7_dot_7_dot_0/logstash_minus_core/lib/logstash//Users/andreletterer/Downloads/tools/logstash-7.7.0/logstash-core/lib/logstash/java_pipeline.rb:279)
	at org.jruby.RubyProc.call(org/jruby/RubyProc.java:318)
	at java.lang.Thread.run(java/lang/Thread.java:832)