[OVSDB-140] When large JSON responses are received by the switch in response to ODL queries, ODL's OVSDB interface becomes unusable.

Duplicate — Thu, 19 Oct 2017 21:28:15 +0000

A little more detail:

It appears to me that the ODL OVSDB subsystem sends an initial query to the switch when an OVSDB connection comes up
If the response to this query is 'too large' (current 100,000 bytes), ODL closes the connection.
If the switch is configured to open the OVSDB connection, this process repeats indefinitely and the OVSDB subsystem isn't usable (at least for that switch)

A lot of detail:

Running code that I built myself from the stable/helium branch (more or less at stable helium 2).

I had one switch in my system with A LOT of ovsdb rows and I hit this problem

My switch is configured to connect to my controller when the controller starts up.
My controller starts and the switch connects
The OVSDB subsystem begins pulling information from my switch
My controller closes the OVSDB connection
My switch attempts to reconnect
repeat forever

I eventually was able to set a break point and get a stack trace. The problem is in
ovsdb/library/src/main/java/org/opendaylight/ovsdb/lib/jsonrpc/JsonRpcDecoder.java around line 116 (in the decode(ChannelHandlerContext ctx, ByteBuf buf, List<Object> out) method)

for (; i < buf.writerIndex(); i++) {
switch (buf.getByte) {
case '

{': if (!inS) leftCurlies++; break; case '}

':
if (!inS) rightCurlies++;
break;
case '"':

{ if (buf.getByte(i - 1) != '\\') inS = !inS; break; }

}

if (leftCurlies != 0 && leftCurlies == rightCurlies && !inS)

{ ByteBuf slice = buf.readSlice(1 + i - buf.readerIndex()); JsonParser jp = jacksonJsonFactory.createParser(new ByteBufInputStream(slice)); JsonNode root = jp.readValueAsTree(); out.add(root); leftCurlies = rightCurlies = lastRecordBytes = 0; recordsRead++; break; }

if (i - buf.readerIndex() >= maxFrameLength)

{ fail(ctx, i - buf.readerIndex()); }

...

private void fail(ChannelHandlerContext ctx, long frameLength) {
logger.error("JSON too big. JSON content exceeded limit of {} bytes", maxFrameLength);
if (frameLength > 0)

{ ctx.fireExceptionCaught( new TooLongFrameException( "frame length exceeds " + maxFrameLength + ": " + frameLength + " - discarded")); }

else

{ ctx.fireExceptionCaught( new TooLongFrameException( "frame length exceeds " + maxFrameLength + " - discarding")); }

}

OpenDaylight JIRA

[OVSDB-140] When large JSON responses are received by the switch in response to ODL queries, ODL's OVSDB interface becomes unusable.