ovsdb-server: Send update for _version for changes due to weak ref removal.

When a row was deleted, and that caused the transaction manager to remove
a remaining weak reference to the row, and no other change had been made
to the row in that transaction, and a client was monitoring modifications
of the _version column in the row, then the monitor update for the column
did not include the old contents of the _version column, even though it
should have.  This commit fixes the problem.

Probably most clients only look at the new value of the column, if they
monitor _version at all, and this bug is really old, so it's probably
not a serious bug.

Found by inspection.

Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Andy Zhou <azhou@nicira.com>
Revert "jsonrpc-server: Add test for disconnecting connections with too long queues."

This reverts commit 631583739f9aec55d4cbe25fb856143ccde48ab6.

Connections that queue up too much data, because they are monitoring a
table that is changing quickly and failing to keep up with the updates,
cause problems with buffer management.  Since commit 60533a405b2e
(jsonrpc-server: Disconnect connections that queue too much data.),
ovsdb-server has dealt with them by disconnecting the connection and
letting them start up again with a fresh copy of the database.  However,
this is not ideal because of situations where disconnection happens
repeatedly.  For example:

     - A manager toggles a column back and forth between two or more values
       quickly (in which case the data transmitted over the monitoring
       connections always increases quickly, without bound).

     - A manager repeatedly extends the contents of some column in some row
       (in which case the data transmitted over the monitoring connection
       grows with O(n**2) in the length of the string).

A better way to deal with this problem is to combine updates when they are
sent to the monitoring connection, if that connection is not keeping up.
In both the above cases, this reduces the data that must be sent to a
manageable amount.  An upcoming patch implements this new way.  This commit
reverts part of the previous solution that disconnects backlogged
connections, since it is no longer useful.

Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Andy Zhou <azhou@nicira.com>
Revert "jsonrpc-server: Disconnect connections that queue too much data."

This reverts commit 60533a405b2eb77214b767767fe143c8645f82d5.

Connections that queue up too much data, because they are monitoring a
table that is changing quickly and failing to keep up with the updates,
cause problems with buffer management.  Since commit 60533a405b2e
(jsonrpc-server: Disconnect connections that queue too much data.),
ovsdb-server has dealt with them by disconnecting the connection and
letting them start up again with a fresh copy of the database.  However,
this is not ideal because of situations where disconnection happens
repeatedly.  For example:

     - A manager toggles a column back and forth between two or more values
       quickly (in which case the data transmitted over the monitoring
       connections always increases quickly, without bound).

     - A manager repeatedly extends the contents of some column in some row
       (in which case the data transmitted over the monitoring connection
       grows with O(n**2) in the length of the string).

A better way to deal with this problem is to combine updates when they are
sent to the monitoring connection, if that connection is not keeping up.
In both the above cases, this reduces the data that must be sent to a
manageable amount.  An upcoming patch implements this new way.  This commit
reverts part of the previous solution that disconnects backlogged
connections, since it is no longer useful.

Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Andy Zhou <azhou@nicira.com>
Revert "ovsdb-data: New functions for predicting serialized length of data."

This reverts commit 0ea7bec76d804a2c4efccd3dbdaa3e30cf536a5c.

Connections that queue up too much data, because they are monitoring a
table that is changing quickly and failing to keep up with the updates,
cause problems with buffer management.  Since commit 60533a405b2e
(jsonrpc-server: Disconnect connections that queue too much data.),
ovsdb-server has dealt with them by disconnecting the connection and
letting them start up again with a fresh copy of the database.  However,
this is not ideal because of situations where disconnection happens
repeatedly.  For example:

     - A manager toggles a column back and forth between two or more values
       quickly (in which case the data transmitted over the monitoring
       connections always increases quickly, without bound).

     - A manager repeatedly extends the contents of some column in some row
       (in which case the data transmitted over the monitoring connection
       grows with O(n**2) in the length of the string).

A better way to deal with this problem is to combine updates when they are
sent to the monitoring connection, if that connection is not keeping up.
In both the above cases, this reduces the data that must be sent to a
manageable amount.  An upcoming patch implements this new way.  This commit
reverts part of the previous solution that disconnects backlogged
connections, since it is no longer useful.

Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Andy Zhou <azhou@nicira.com>
Revert "json: New function json_serialized_length()."

This reverts commit 1600fa6853872e16130366351a2c14f6fa8b547c.

Connections that queue up too much data, because they are monitoring a
table that is changing quickly and failing to keep up with the updates,
cause problems with buffer management.  Since commit 60533a405b2e
(jsonrpc-server: Disconnect connections that queue too much data.),
ovsdb-server has dealt with them by disconnecting the connection and
letting them start up again with a fresh copy of the database.  However,
this is not ideal because of situations where disconnection happens
repeatedly.  For example:

     - A manager toggles a column back and forth between two or more values
       quickly (in which case the data transmitted over the monitoring
       connections always increases quickly, without bound).

     - A manager repeatedly extends the contents of some column in some row
       (in which case the data transmitted over the monitoring connection
       grows with O(n**2) in the length of the string).

A better way to deal with this problem is to combine updates when they are
sent to the monitoring connection, if that connection is not keeping up.
In both the above cases, this reduces the data that must be sent to a
manageable amount.  An upcoming patch implements this new way.  This commit
reverts part of the previous solution that disconnects backlogged
connections, since it is no longer useful.

Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Andy Zhou <azhou@nicira.com>
jsonrpc-server: Track monitor updates separately from sending them.

This will make combining monitor updates easier in the next commit.

Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Andy Zhou <azhou@nicira.com>
jsonrpc-server: Combine notifications when connection becomes backlogged.

Connections that queue up too much data, because they are monitoring a
table that is changing quickly and failing to keep up with the updates,
cause problems with buffer management.  Since commit 60533a405b2e
(jsonrpc-server: Disconnect connections that queue too much data.),
ovsdb-server has dealt with them by disconnecting the connection and
letting them start up again with a fresh copy of the database.  However,
this is not ideal because of situations where disconnection happens
repeatedly.  For example:

     - A manager toggles a column back and forth between two or more values
       quickly (in which case the data transmitted over the monitoring
       connections always increases quickly, without bound).

     - A manager repeatedly extends the contents of some column in some row
       (in which case the data transmitted over the monitoring connection
       grows with O(n**2) in the length of the string).

A better way to deal with this problem is to combine updates when they are
sent to the monitoring connection, if that connection is not keeping up.
In both the above cases, this reduces the data that must be sent to a
manageable amount.  This commit implements this new way.

Bug #1211786.
Bug #1221378.
Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Andy Zhou <azhou@nicira.com>
unit-test: Improve ovstest user interface

Improve help output. Running without argument now exit with an error
message and an error code. Simplify OVSTEST_REGISTER() since not all
test programs uses sub_commands.

Signed-off-by: Andy Zhou <azhou@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>
unit-test: Link 29 test programs into ovstest

Improve link speed by linking 29 test programs into ovstest.

On my machine, running the following command against a fully
built tree:

  $ touch lib/random.c; time make

Improve the overall build time from 7 seconds to 3.5 seconds.

Signed-off-by: Andy Zhou <azhou@nicira.com>
Acked-by: Ben Pfaff <blp@nicira.com>