Understanding common error messages
Skipping add replicas
When a new node has joined the cluster or an existing node has been removed, you may see errors messages similar to the following:
W1001 10:23:00.969424 22338 cluster_balance.cc:232] Skipping add replicas for 21d0a966e9c048978e35fad3cee31698: Operation failed. Try again. Cannot add replicas. Currently have a total overreplication of 1, when max allowed is 1
This message is harmless and can be ignored. It means that the maximum number of concurrent tablets being remotely bootstrapped across the cluster by the YB-Master load balancer has reached its limit. This limit is configured in
--load_balancer_max_concurrent_tablet_remote_bootstraps in yb-master config.
SST files limit exceeded
The following error is emitted when the number of SST files has exceeded its limit:
Service unavailable (yb/tserver/tablet_service.cc:257): SST files limit exceeded 58 against (24, 48), score: 0.35422774182913203: 3.854s (tablet server delay 3.854s)
Usually, the client is running a high INSERT/UPDATE/DELETE workload and compactions are falling behind.
To determine why this error is happening, you can check the disk bandwidth, network bandwidth, and find out if enough CPU is available in the server.
The limits are controlled by the following YB-TServer configuration flags:
Catalog Version Mismatch: A DDL occurred while processing this query. Try Again.
When executing queries in the YSQL layer, the query may fail with the following error:
org.postgresql.util.PSQLException: ERROR: Catalog Version Mismatch: A DDL occurred while processing this query. Try Again
A DML query in YSQL may touch multiple servers, and each server has a Catalog Version which is used to track schema changes. When a DDL statement runs in the middle of the DML query, the Catalog Version is changed and the query has a mismatch, causing it to fail.
In these cases, the database aborts the query and returns a
40001 PostgreSQL error code. Errors with this code can be safely retried from the client side.