Jan Høydahl created SOLR-18144:
----------------------------------
Summary: Regression in Schema Designer and .system collection
Key: SOLR-18144
URL: https://issues.apache.org/jira/browse/SOLR-18144
Project: Solr
Issue Type: Bug
Components: Schema Designer
Affects Versions: 9.10.1, 9.10, 9.9
Reporter: Jan Høydahl
When using Schema designer in solr 9.9 or 9.10, it complains with an error
message "Collection not found: .system". We first thought it was related to
SOLR-15832 but it turns out to be a new bug. Here is an analysis by Claude Code
which I believe is accurate.
h2. Root Cause
The regression was introduced by commit 82c50e4291e (SOLR-16503: Use
Http2SolrClient in SolrClientCache, SchemaDesigner, cherry-picked to branch_9x
on Feb 10, 2025).
h3. What Changed
SchemaDesignerConfigSetHelper was migrated from using raw HTTP via
CloudLegacySolrClient.getHttpClient() to using GenericSolrRequest +
CloudSolrClient.
Before (CloudLegacySolrClient.getHttpClient().execute(httpPost)):
- Bypassed CloudSolrClient's ZooKeeper collection validation entirely
- The raw HTTP POST arrived at the Solr servlet (HttpSolrCall)
- HttpSolrCall.autoCreateSystemColl() detected: POST + .system not in ZK →
auto-created the collection
- getStoredSampleDocs used raw HTTP GET; HTTP 404 was explicitly handled as
"not found is OK"
After (request.process(cloudClient, BLOB_STORE_ID)):
- CloudSolrClient performs a ZooKeeper lookup before sending any HTTP request
- If .system doesn't exist in ZK → immediately throws
SolrException("Collection not found: .system")
- HttpSolrCall.autoCreateSystemColl() is never reached → .system is never
auto-created
- getStoredSampleDocs now only catches SolrServerException, not SolrException
— so "Collection not found" propagates up
h3. Fix Options
# Best for branch_9x: Before any blob operation in
SchemaDesignerConfigSetHelper, check if .system exists and explicitly create it
(CollectionAdminRequest.createCollection(SYSTEM_COLL, null, 1, 1)). Also fix
getStoredSampleDocs to catch SolrException for the "not found" case (like the
old HTTP 404 handling).
# Also fix getStoredSampleDocs: Add SolrException to the catch block and
return Collections.emptyList() when the collection doesn't exist — matching the
old behavior where HTTP 404 was silently treated as "no documents stored.
# Long-term/main: The main branch already has the proper fix — commit
242c1fc4e8a (SOLR-17852) migrated Schema Designer entirely to the FileStore
API, eliminating .system / BlobStore dependency. This backport would be more
work but more correct.
The most targeted fix would be to ensure .system is created lazily in
SchemaDesignerConfigSetHelper before blob reads/writes, and to also fix
getStoredSampleDocs to handle the "collection not found" case gracefully.
--
This message was sent by Atlassian Jira
(v8.20.10#820010)
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
