In jira-application.properties, we say that JIRA should wait at most 30s to an index lock before giving up:

# Specified the 'wait time' for a file lock in the Lucene IssueIndexManager (in milliseconds)
# This value should only be modified if you are seeing a jira.issue.index.DefaultIndexManager 'Giving up reindex' ERROR
# in your log files or requested to do so by Atlassian support.
jira.index.lock.waittime=30000

For an average size JIRA (33k issues) on average hardware, JIRA's nightly index optimization takes 48s. On the ASF JIRA, 75k issues takes 208s. If any write operation takes place during this time it will fail.

Clearly, 30s hangs are not outside the bounds of possibility. Could we increase this to 300s or something?