LYD031106 commented on issue #2209: URL: https://github.com/apache/incubator-hugegraph/issues/2209#issuecomment-3410891988
Hello everyone, I've conducted a preliminary analysis on Issue [#2209 The backend store version is inconsistent](https://github.com/apache/incubator-hugegraph/issues/2209), specifically focusing on the behavior when **MySQL** is used as the backend store. ### 🐞 Problem Analysis 1. **Key File:** The core logic resides in [`hugegraph-server/hugegraph-mysql/src/main/java/org/apache/hugegraph/backend/store/mysql/MysqlTables.java`](https://github.com/apache/incubator-hugegraph/blob/master/hugegraph-server/hugegraph-mysql/src/main/java/org/apache/hugegraph/backend/store/mysql/MysqlTables.java). 2. **Symptom:** During server startup (including restarts and normal operations), the version check fails because the metadata table for version information (the `m` table in MySQL) is empty, even though the overall database (Store) exists. 3. **Root Cause (Detailed):** * When the server starts, the version check logic calls `readVersion()`. Since the `m` table is empty, `readVersion()` returns `null`, leading to a version inconsistency error. * The primary mechanism for writing the version, `writeVersion()`, is located within the `initStore()` method. * During a non-initial startup, if `backendStoreInfo. exists()` returns `true` (indicating the database is present), `initStore()` skips the complete database re-initialization (which would include calling `writeVersion()`). * Consequently, the empty `m` table is not updated, the version check fails, and the initialization process terminates. ### 💡 Proposed Solution My initial proposal is to **ensure that `writeVersion` is called unconditionally within the `initStore` process**, provided the database exists. This would guarantee that the version number is correctly written or updated to the backend store's metadata table, regardless of whether the database is being initialized for the first time or is simply being re-opened after a restart. I hope we can have a further discussion on this analysis and proposed fix to confirm the optimal approach, and I am ready to participate in implementing the solution. Looking forward to your feedback! -- 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]
