Backport: Optimize RDB load performance and fix cluster mode resizing on replica side (#1199)#1328
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zuiderkwast merged 1 commit intovalkey-io:8.0from Apr 15, 2025
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…a side (valkey-io#1199) This PR addresses two issues: 1. Performance Degradation Fix - Resolves a significant performance issue during RDB load on replica nodes. - The problem was causing replicas to rehash multiple times during the load process. Local testing demonstrated up to 50% degradation in BGSAVE time. - The problem occurs when the replica tries to expand pre-created slot dictionaries. This operation fails quietly, resulting in undetected performance issues. - This fix aims to optimize the RDB load process and restore expected performance levels. 2. Bug fix when reading `RDB_OPCODE_RESIZEDB` in Valkey 8.0 cluster mode- - Use the shard's master slots count when processing this opcode, as `clusterNodeCoversSlot` is not initialized for the currently syncing replica. - Previously, this problem went unnoticed because `RDB_OPCODE_RESIZEDB` had no practical impact (due to 1). These improvements will enhance overall system performance and ensure smoother upgrades to Valkey 8.0 in the future. Testing: - Conducted local tests to verify the performance improvement during RDB load. - Verified that ignoring `RDB_OPCODE_RESIZEDB` does not negatively impact functionality in the current version. Signed-off-by: naglera <[email protected]> Co-authored-by: Binbin <[email protected]> (cherry picked from commit c5012cc) Signed-off-by: naglera <[email protected]>
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Additional details and impacted files@@ Coverage Diff @@
## 8.0 #1328 +/- ##
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- Coverage 70.66% 70.62% -0.04%
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Files 114 114
Lines 61681 62951 +1270
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+ Hits 43585 44458 +873
- Misses 18096 18493 +397
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…e the hashtable
If we want to expand kvstoreHashtableExpand, we need to make sure the
hashtable exists. Currently, when processing RDB slot-info, our expand
has no effect because the hashtable does not exist (we initialize it only
when we need it).
```
if (server.cluster_enabled) {
/* In cluster mode we resize individual slot specific dictionaries based on the number of keys that
* slot holds. */
kvstoreHashtableExpand(db->keys, slot_id, slot_size);
kvstoreHashtableExpand(db->expires, slot_id, expires_slot_size);
should_expand_db = 0;
}
```
We also update kvstoreExpand to use the kvstoreHashtableExpand to make
sure there is only one code path. Also see valkey-io#1328 for more details.
Signed-off-by: Binbin <[email protected]>
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This PR addresses two issues:
RDB_OPCODE_RESIZEDBin Valkey 8.0 cluster mode-clusterNodeCoversSlotis not initialized for the currently syncing replica.RDB_OPCODE_RESIZEDBhad no practical impact (due to 1).These improvements will enhance overall system performance and ensure smoother upgrades to Valkey 8.0 in the future.
Testing:
RDB_OPCODE_RESIZEDBdoes not negatively impact functionality in the current version.(cherry picked from commit c5012cc)