We used the solr Upgrader and were able to migrate from 5 to 6 to 7. For example java -cp lucene-core-7.7.3.jar:lucene-backward-codecs-7.7.3.jar org.apache.lucene.index.IndexUpgrader -delete-prior-commits -verbose $index
After each migration we used the CheckIndex to confirm and indeed it reported expected version. For example java -ea:org.apache.lucene... -cp lucene-core-7.7.3.jar:lucene-backward-codecs-7.7.3.jar org.apache.lucene.index.CheckIndex When we tried to upgrade from 7 to 8, that failed with a complaint that the index was still version 6 and updating could only be from the previious (ie 7) version. Indeed running the 8 CheckIndex reported the index was version 6, even though the 7 CheckIndex reported version 7. Oh well, so we're trying another approach. Using the fieldtypes, fields, dynamicfileds, and copyfields API, we copy the schema from 5 to 8. Then we extract the documents as json from 5 and update the json to 8. For example curl -X GET "$SRC/select?q=*%3A*&wt=json&indent=true&start=$start&rows=10" > $tmp 2>/dev/null jq ".response.docs" <$tmp >$tmp2 curl -X POST -H 'Content-type:application/json' --data-binary @$tmp2 "$DST/update/json/docs?commit=true" The documents are showing up in 8. We still need to perform some validation, but are we overlooking some obvious reason, why this might fail? Thanks, Ron
