I use Elasticsearch for Mediawiki (MW 1.31, CentOS 7.6) and the system autoupgraded Elasticsearch from 5.6.13 to 5.6.14. I upgraded the the plugins to same versions, reindexed, appeared to complete successfully, but the search function does not bring results. When checking the data files I see very small files. I get:
curl localhost:9200/_cat/indices?v
health status index uuid pri rep docs.count docs.deleted store.size pri.store.size
green open wiki_1_31_0_content_first KOLZXJrpTle_kDQOuS-sYQ 4 0 0 0 648b 648b
green open mw_cirrus_metastore_first KWF6MOHuSQOd-d4QCp9zbg 1 0 3 6 11.2kb 11.2kb
green open wiki_1_31_0_general_first NHAdshY6Sc-wa5s590gPHw 4 0 33 0 13.2kb 13.2kb