I have a question regarding postgresql waiting for the client. I queried the pg_stat_activity because I noticed a connection that had not been released for days!!! I saw that the wait_event was ClientRead and the query was ROLLBACK. What the server is waiting for from the client? It is a simple ROLLBACK. I'd expect postgresql to abort the transaction, that's it! This was the client thread stack trace:
at sun.nio.ch.Net.poll(Native Method) at sun.nio.ch.NioSocketImpl.park() at sun.nio.ch.NioSocketImpl.park() at sun.nio.ch.NioSocketImpl.implRead() at sun.nio.ch.NioSocketImpl.read() at sun.nio.ch.NioSocketImpl$1.read() at java.net.Socket$SocketInputStream.read() at sun.security.ssl.SSLSocketInputRecord.read() at sun.security.ssl.SSLSocketInputRecord.readFully() at sun.security.ssl.SSLSocketInputRecord.decodeInputRecord() at sun.security.ssl.SSLSocketInputRecord.decode() at sun.security.ssl.SSLTransport.decode() at sun.security.ssl.SSLSocketImpl.decode() at sun.security.ssl.SSLSocketImpl.readApplicationRecord() at sun.security.ssl.SSLSocketImpl$AppInputStream.read() at org.postgresql.core.VisibleBufferedInputStream.readMore(VisibleBufferedInputStream.java:161) at org.postgresql.core.VisibleBufferedInputStream.ensureBytes(VisibleBufferedInputStream.java:128) at org.postgresql.core.VisibleBufferedInputStream.ensureBytes(VisibleBufferedInputStream.java:113) at org.postgresql.core.VisibleBufferedInputStream.read(VisibleBufferedInputStream.java:73) at org.postgresql.core.PGStream.receiveChar(PGStream.java:453) at org.postgresql.core.v3.QueryExecutorImpl.processResults(QueryExecutorImpl.java:2120) at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:356) at org.postgresql.core.v3.QueryExecutorImpl.execute(QueryExecutorImpl.java:316) at org.postgresql.jdbc.PgConnection.executeTransactionCommand(PgConnection.java:879) at org.postgresql.jdbc.PgConnection.rollback(PgConnection.java:922) at com.zaxxer.hikari.pool.ProxyConnection.rollback(ProxyConnection.java:396) at com.zaxxer.hikari.pool.HikariProxyConnection.rollback(HikariProxyConnection.java) at org.hibernate.resource.jdbc.internal.AbstractLogicalConnectionImplementor.rollback(AbstractLogicalConnectionImplementor.java:121) at org.hibernate.resource.transaction.backend.jdbc.internal.JdbcResourceLocalTransactionCoordinatorImpl$TransactionDriverControlImpl.rollback(JdbcResourceLocalTransactionCoordinatorImpl.java:304) at org.hibernate.engine.transaction.internal.TransactionImpl.rollback(TransactionImpl.java:142) at org.springframework.orm.jpa.JpaTransactionManager.doRollback(JpaTransactionManager.java:589) ... So I ended up in a situation where both client and server were reading from the socket :(. I'm not sure why. Something went wrong between client and server, network problems? The connection was held for 5 days until it was manually terminated. But why the server was waiting in the first place? -- Simone Giusso
