Use this page to identify common Hologres issues by their error messages and symptoms, then go to the relevant troubleshooting guide.
Out of memory (OOM)
Error: Total memory used by all existing queries exceeded memory limitation.
In most cases, a query has exceeded the instance memory limit. See Troubleshoot OOM issues.
Performance degradation
If queries or data writes are slower than expected, optimize SQL queries by following the guide that matches your scenario:
Optimize query performance — slow queries on Hologres internal tables
Performance tuning for MaxCompute foreign tables — slow queries on MaxCompute foreign tables
Read/write performance tuning — slow data writes or updates
Best practices for fast point queries — high-latency key-value lookups
High CPU or long-running queries
If sustained high CPU load is affecting your online business, or metrics show a query has been running far longer than expected, a superuser can view and cancel active queries from the Active Query page in HoloWeb. See the "Use HoloWeb to view and manage active queries in a visualized way" section in Manage queries.
Connection errors
Errors:
terminating connection due to idle state timeoutterminating connection due to idle-session timeoutremaining connection slots are reserved for non-replication superuser connections
These errors indicate that the instance has hit its connection limit or a connection has timed out. As a superuser, manage the number of connections, close connections that do not meet your expectations, or adjust the connection timeout period. See Manage connections.
SQL errors
Errors: bigint out of range · division by zero
These errors point to a SQL logic issue in the query. See Hologres SQL FAQ.
Permission errors
Errors: permission denied · cloud authentication failed · you have no privilege
Troubleshoot based on the specific error message. See Permissions FAQ.
MaxCompute foreign table errors
Errors:
Failed to get MaxCompute table:Not enable schema evolutionFailed to get MaxCompute table:Not enable acid tableERROR: not an ORC file
See MaxCompute FAQ.
Flink integration issues
Errors: ERPC CONNECTION CLOSED · Read timed out
If Flink reads from or writes to Hologres are failing or degraded, see Flink/Blink troubleshooting.
Metrics
Use instance metrics to understand what is happening inside Hologres — including which queries are consuming the most resources and whether performance has changed over time. See Metrics.