Yunus Evren ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=557058%... ) *updated* an issue Hibernate ORM ( https://hibernate.atlassian.net/browse/HHH?atlOrigin=eyJpIjoiZTJkODIyMDY3... ) / Bug ( https://hibernate.atlassian.net/browse/HHH-16594?atlOrigin=eyJpIjoiZTJkOD... ) HHH-16594 ( https://hibernate.atlassian.net/browse/HHH-16594?atlOrigin=eyJpIjoiZTJkOD... ) Query cache miss when query contains multiple parameters ( https://hibernate.atlassian.net/browse/HHH-16594?atlOrigin=eyJpIjoiZTJkOD... ) Change By: Yunus Evren ( https://hibernate.atlassian.net/secure/ViewProfile.jspa?accountId=557058%... ) When query caching is enabled on a query that contains multiple query parameters, subsequent queries with the exact same parameters run into cache misses. This seems to be caused because {{QueryKey.ParameterBindingsMementoImpl}} is constructed with a random order of parameter bindings in each different transaction. See {{generateQueryKeyMemento()}} method: [https://github.com/hibernate/hibernate-orm/blob/6.2.2/hibernate-core/src/...] {{parameterBindingMap}} is a {{ConcurrentHashMap}} that will have an unpredictable order in each session. This method iterates over the values of this map and alters the {{hashCode}} of the cache key on each {{addToCacheKey()}} call. Different order of parameters result in {{ParameterBindingsMemento}} objects with different {{hashCode}} values even though they consist of exact identical parameters. This eventually results in a cache miss because the cache key object ({{QueryKey}}) equals method will return false when comparing the inner ParameterBindingsMemento objects that have different {{hashCode}}s: [https://github.com/hibernate/hibernate-orm/blob/6.2.2/hibernate-core/src/...] The issue does not occur when query contains only 1 parameter because the order will be unchanged. If the query contains 2 parameters, then you have 50% chance for miss. If it has more parameters the possibility to miss increases exponentially. This is impacting the performance of the application quite severely because queries that have e.g. 7 parameters have 1/5040 (7 factorial) chance to do a cache hit the second time. So in practice, query cache is more or less not working at all for these queries. Reproducer test case to be added , work in progress…. ( https://hibernate.atlassian.net/browse/HHH-16594#add-comment?atlOrigin=ey... ) Add Comment ( https://hibernate.atlassian.net/browse/HHH-16594#add-comment?atlOrigin=ey... ) Get Jira notifications on your phone! Download the Jira Cloud app for Android ( https://play.google.com/store/apps/details?id=com.atlassian.android.jira.... ) or iOS ( https://itunes.apple.com/app/apple-store/id1006972087?pt=696495&ct=Em... ) This message was sent by Atlassian Jira (v1001.0.0-SNAPSHOT#100225- sha1:84d3b45 )