The new comment reflects with more clarity what ovsdb_idl_add_table() does.
Previous comment could be misunderstood, leading to believe that this function
replicates all columns on IDL. Hopefully this fix clarifies that columns are
not replicated, just minimal data for reference integrity is replicated.
A comment in ovsdb_idl_table_class is also modified to better reflect this
behaviour.
Signed-off-by: Edward Aymerich <edward.aymerich@hpe.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>
Ovsdb-idl notifies a client that something changed; it does not track
which table, row changed in what way (insert, modify or delete).
As a result, a client has to scan or reconfigure the entire idl after
ovsdb_idl_run(). This is presumably fine for typical ovs schemas where
tables are relatively small. In use-cases where ovsdb is used with
schemas that can have very large tables, the current ovsdb-idl
notification mechanism does not appear to scale - clients need to do a
lot of processing to determine the exact change delta.
This change adds support for:
- Table and row based change sequence numbers to record the
most recent IDL change sequence numbers associated with insert,
modify or delete update on that table or row.
- Change tracking of specific columns. This ensures that changed
rows (inserted, modified, deleted) that have tracked columns, are
tracked by IDL. The client can directly access the changed rows
with get_first, get_next operations without the need to scan the
entire table.
The tracking functionality is not enabled by default and needs to
be turned on per-column by the client after ovsdb_idl_create()
and before ovsdb_idl_run().
/* Example Usage */
idl = ovsdb_idl_create(...);
/* Track specific columns */
ovsdb_idl_track_add_column(idl, column);
/* Or, track all columns */
ovsdb_idl_track_add_all(idl);
for (;;) {
ovsdb_idl_run(idl);
seqno = ovsdb_idl_get_seqno(idl);
/* Process only the changed rows in Table FOO */
FOO_FOR_EACH_TRACKED(row, idl) {
/* Determine the type of change from the row seqnos */
if (foo_row_get_seqno(row, OVSDB_IDL_CHANGE_DELETE)
>= seqno)) {
printf("row deleted\n");
} else if (foo_row_get_seqno(row, OVSDB_IDL_CHANGE_MODIFY)
>= seqno))
printf("row modified\n");
} else if (foo_row_get_seqno(row, OVSDB_IDL_CHANGE_INSERT)
>= seqno))
printf("row inserted\n");
}
}
/* All changes processed - clear the change track */
ovsdb_idl_track_clear(idl);
}
Signed-off-by: Shad Ansari <shad.ansari@hp.com>
Signed-off-by: Ben Pfaff <blp@ovn.org>
struct list is a common name and can't be used in public headers.
Signed-off-by: Thomas Graf <tgraf@noironetworks.com>
Acked-by: Ben Pfaff <blp@nicira.com>
OVSDB has always had the ability to mark a column as "immutable", so that
its value cannot be changed in a given row after that row is initially
inserted. However, we discovered recently that ovsdb-server has never
enforced this constraint. This commit implements enforcement.
Reported-by: Paul Ingram <paul@nicira.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
Acked-by: Kyle Mestery <kmestery@cisco.com>
String to string maps are used all over the Open vSwitch database.
Before this patch, they were implemented in the idl as parallel
string arrays. This strategy has proven a bit cumbersome. With
this patch, string to string maps are implemented using the smap
library.
Signed-off-by: Ethan Jackson <ethan@nicira.com>
Replaced all instances of Nicira Networks(, Inc) to Nicira, Inc.
Feature #10593
Signed-off-by: Raju Subramanian <rsubramanian@nicira.com>
Signed-off-by: Ben Pfaff <blp@nicira.com>
Until now, by default the IDL replicated all tables and all columns in the
database, and a few functions made it possible to avoid replicating
selected columns. This commit adds a mode in which nothing is replicated
by default and the client code is responsible for specifying each column
and table that it is interested in. The following commit adds a user for
this mode.
ovs-vswitchd has no need to replicate some parts of the database. In
particular, it doesn't need to replicate the bits that it never reads,
such as the external_ids column in the Open_vSwitch table. This saves
some memory, CPU time, and bandwidth to the database.
Another type of column that benefits from special treatment is "write-only
columns", that is, those that ovs-vswitchd writes and keeps up-to-date but
never expects another client to write, such as the cur_cfg column in the
Open_vSwitch table. If the IDL reports that the database has changed when
ovs-vswitchd updates such a column, then ovs-vswitchd reconfigures itself
for no reason, wasting CPU time. This commit also adds support for such
columns.
This also adds protocol compatibility to the database itself and to
ovsdb-client. It doesn't actually add multiple database support to
ovsdb-server, since we don't really need that yet.
ovs-vsctl wants to use these functions directly, so make them available
through the ovsdb-idl public header instead of only through the private
one.
Also, change the prototypes to make them usable without casts.
The IDL is intended to allow clients easier access to data in the database
by providing an extra layer of abstraction. However, ovs-vsctl needs to
also provide generic access to database tables, rows, and columns, and
until now the IDL has not allowed this. In particular, there was no way
to modify the value of a database column by providing a "struct
ovsdb_datum" with the new value and then have that reflected in the IDL
structs, although the other direction was possible.
This commit fixes that problem, which requires a bit of refactoring of the
IDL layer. It also exposes the interface for iterating through table
records to clients directly, by moving it from the "private" IDL header to
the public one.
