u70b3 opened a new pull request, #66452:
URL: https://github.com/apache/doris/pull/66452

   ### What problem does this PR solve?
   
   Issue Number: close #66025
   
   Problem Summary:
   
   In the external session-bypass path (e.g. Iceberg REST `session=user`, where 
the shared table-name cache is bypassed so one user's visible table set is 
never served to another), `ExternalDatabase.getTables()` performs **1 + N 
remote table-name enumerations** for N tables:
   
   1. `getTables()` calls `getTableNamesWithLock()`, which enumerates remote 
table names once via `listLocalTableNamesWithoutCache(sessionContext)`.
   2. It then iterates the names and calls `getTableNullable(tblName)` per 
table.
   3. In bypass mode that enters `getTableNullableWithoutCache(sessionContext, 
tableName)`.
   4. Which calls `findTableNamePairWithoutCache(...)` — a **full 
`listTableNames(sessionContext)` scan per table**.
   
   Listing N tables therefore triggers 1 + N remote `LIST TABLES` calls, which 
is very slow against a remote catalog with many tables.
   
   **Fix:** in the bypass branch, enumerate once via 
`listTableNames(sessionContext)` and build every table from that single 
snapshot. Semantics are preserved:
   
   - The single enumeration still runs the case-insensitive conflict check 
inside `listTableNames`, so conflicting remote names keep failing the whole 
listing (pinned by a new test).
   - Local-name dedup keeps the previous `Set` + `findFirst()` first-win 
semantics when two remote names map to the same local name.
   - Per-table build failures are still logged and skipped, exactly as before.
   
   **Verification:** a unit test counting remote listings shows 4 enumerations 
for 3 tables before the fix and exactly 1 after.
   
   ### Release note
   
   None
   
   ### Check List (For Author)
   
   - Test <!-- At least one of them must be included. -->
       - [ ] Regression test
       - [x] Unit Test
       - [ ] Manual test (add detailed scripts or steps below)
       - [ ] No need to test or manual test. Explain why:
           - [ ] This is a refactor/code format and no logic has been changed.
           - [ ] Previous test can cover this change.
           - [ ] No code files have been changed.
           - [ ] Other reason <!-- Add your reason?  -->
   
   - Behavior changed:
       - [x] No.
       - [ ] Yes. <!-- Explain the behavior change -->
   
   - Does this need documentation?
       - [x] No.
       - [ ] Yes. <!-- Add document PR link here. eg: 
https://github.com/apache/doris-website/pull/1214 -->
   
   ### Check List (For Reviewer who merge this PR)
   
   - [ ] Confirm the release note
   - [ ] Confirm test cases
   - [ ] Confirm document
   - [ ] Add branch pick label <!-- Add branch pick label that this PR should 
merge into -->


-- 
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.

To unsubscribe, e-mail: [email protected]

For queries about this service, please contact Infrastructure at:
[email protected]


---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]

Reply via email to