Re: [Possible Bug] EnableSSL method has no socket timeout, thread hangs indefinitely

Dave Cramer

davec(at)postgresintl(dot)com
www.postgresintl.com

On Fri, 7 Dec 2018 at 18:54, Ray Hu <rayhu92(at)gmail(dot)com> wrote:

> Hi all
>
> During my usage of the JDBC library, I was performing some error handling
> tests by introducing network packet loss between my application and the
> database and I found that my application’s thread count began rising, I did
> a thread dump of my application and found many of the following stack trace:
>
> "PostgreSQL JDBC driver connection thread" #4645 daemon prio=5 os_prio=0
> tid=0x967d7c00 nid=0x6c8e runnable [0x901ac000]
> java.lang.Thread.State: RUNNABLE
> at java.net.SocketInputStream.socketRead0(Native Method)
> at
> java.net.SocketInputStream.socketRead(SocketInputStream.java:116)
> at java.net.SocketInputStream.read(SocketInputStream.java:171)
> at java.net.SocketInputStream.read(SocketInputStream.java:141)
> at sun.security.ssl.InputRecord.readFully(InputRecord.java:465)
> at sun.security.ssl.InputRecord.read(InputRecord.java:503)
> at
> sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:983)
> - locked <0xd1aca150> (a java.lang.Object)
> at
> sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1385)
> - locked <0xd1aca120> (a java.lang.Object)
> at
> sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1413)
> at
> sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1397)
> at
> org.postgresql.ssl.jdbc4.AbstractJdbc4MakeSSL.convert(AbstractJdbc4MakeSSL.java:119)
> at
> org.postgresql.core.v3.ConnectionFactoryImpl.enableSSL(ConnectionFactoryImpl.java:331)
> at
> org.postgresql.core.v3.ConnectionFactoryImpl.openConnectionImpl(ConnectionFactoryImpl.java:125)
> at
> org.postgresql.core.ConnectionFactory.openConnection(ConnectionFactory.java:66)
> at
> org.postgresql.jdbc2.AbstractJdbc2Connection.<init>(AbstractJdbc2Connection.java:127)
> at
> org.postgresql.jdbc3.AbstractJdbc3Connection.<init>(AbstractJdbc3Connection.java:29)
> at
> org.postgresql.jdbc3g.AbstractJdbc3gConnection.<init>(AbstractJdbc3gConnection.java:21)
> at
> org.postgresql.jdbc4.AbstractJdbc4Connection.<init>(AbstractJdbc4Connection.java:41)
> at
> org.postgresql.jdbc4.Jdbc4Connection.<init>(Jdbc4Connection.java:24)
> at org.postgresql.Driver.makeConnection(Driver.java:414)
> at org.postgresql.Driver.access$100(Driver.java:47)
> at org.postgresql.Driver$ConnectThread.run(Driver.java:325)
> at java.lang.Thread.run(Thread.java:748)
>
> These threads were permanently stuck in the above state and they did not
> recover even after the network recovered
>
> I checked the source code of the latest PostgreSQL JDBC library (42.2.5)
> and found the following code:
> In class ConnectionFactoryImpl.java
> Line 85:
> private PGStream tryConnect(String user, String database,
> Properties info, SocketFactory socketFactory, HostSpec hostSpec,
> SslMode sslMode)
> throws SQLException, IOException {
> int connectTimeout = PGProperty.CONNECT_TIMEOUT.getInt(info) * 1000;
>
> PGStream newStream = new PGStream(socketFactory, hostSpec,
> connectTimeout);
>
> // Construct and send an ssl startup packet if requested.
> newStream = enableSSL(newStream, sslMode, info, connectTimeout);
>
> // Set the socket timeout if the "socketTimeout" property has been set.
> int socketTimeout = PGProperty.SOCKET_TIMEOUT.getInt(info);
> if (socketTimeout > 0) {
> newStream.getSocket().setSoTimeout(socketTimeout * 1000);
> }
>
>
> From what I see, the enableSSL method is called *before* the socket
> timeout is set, so when java.net.SocketInputStream.socketRead0 is called,
> it has no timeout and will wait infinitely for its peer to reply back.
> Which matches up with the behavior that I see in my stack trace.
>
> Is this a bug?
>
> Note: I’m aware that the stack trace that I supplied uses an older version
> of the JDBC library, I’ve repeated the test with the latest library
> version and the issue persisted. I can run the tests again and supply the
> new stack trace if needed.
>

Can you file an issue on github https://github.com/pgjdbc/pgjdbc/issues

Thanks,

>
> Thank you
>