SingleStore Managed Service

ERROR 1735: Unable to connect … Timed out reading from socket

Issue

A SingleStore DB node is unable to connect to another SingleStore DB node. This may be because there is no network connectivity (such as a network problem or a firewall blocking connectivity), or because a node is overloaded with connection requests.

Solution

Here are some possible solutions to solve this problem:

  • Ensure that all nodes are able to connect to all other nodes on the configured port (the default is 3306). Update any firewall rules that block connectivity between the nodes.

    One way to verify connectivity is to run the command FILL CONNECTION POOLS on all SingleStore DB nodes. If this fails with the same error, then a node is unable to connect to another node.

    Some queries require different amounts of connectivity. For example, some queries only require aggregator-leaf connections while others require aggregator-leaf as well as leaf-leaf connections. As a result, it is possible for some queries to succeed while others fail with this error.

  • If all nodes are able to connect to all other nodes, the error is likely because your query or queries require opening too many connections at once. Run FILL CONNECTION POOLS on all SingleStore DB nodes to pre-fill connection pools. If the connection pool size is too small for your workload, adjust the max_pooled_connections configuration variable, which controls the number of pooled connections between each pair of nodes.Non-Sync Variables List