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ovsdb-idl: Make selecting tables and columns to replicate more flexible.

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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.
This commit is contained in:
Ben Pfaff
2010-11-16 09:14:52 -08:00
parent cbb7baddb8
commit ef73f86cd4
7 changed files with 168 additions and 79 deletions
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163
lib/ovsdb-idl.c
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@@ -66,7 +66,7 @@ struct ovsdb_idl {
const struct ovsdb_idl_class *class;
struct jsonrpc_session *session;
struct shash table_by_name;
struct ovsdb_idl_table *tables;
struct ovsdb_idl_table *tables; /* Contains "struct ovsdb_idl_table *"s.*/
struct json *monitor_request_id;
unsigned int last_monitor_request_seqno;
unsigned int change_seqno;
@@ -140,13 +140,29 @@ static bool ovsdb_idl_txn_process_reply(struct ovsdb_idl *,
* form acceptable to jsonrpc_session_open(). The connection will maintain an
* in-memory replica of the remote database whose schema is described by
* 'class'. (Ordinarily 'class' is compiled from an OVSDB schema automatically
* by ovsdb-idlc.) */
* by ovsdb-idlc.)
*
* If 'monitor_everything_by_default' is true, then everything in the remote
* database will be replicated by default. ovsdb_idl_omit() and
* ovsdb_idl_omit_alert() may be used to selectively drop some columns from
* monitoring.
*
* If 'monitor_everything_by_default' is false, then no columns or tables will
* be replicated by default. ovsdb_idl_add_column() and ovsdb_idl_add_table()
* must be used to choose some columns or tables to replicate.
*/
struct ovsdb_idl *
ovsdb_idl_create(const char *remote, const struct ovsdb_idl_class *class)
ovsdb_idl_create(const char *remote, const struct ovsdb_idl_class *class,
bool monitor_everything_by_default)
{
struct ovsdb_idl *idl;
uint8_t default_mode;
size_t i;
default_mode = (monitor_everything_by_default
? OVSDB_IDL_MONITOR | OVSDB_IDL_ALERT
: 0);
idl = xzalloc(sizeof *idl);
idl->class = class;
idl->session = jsonrpc_session_open(remote);
@@ -160,7 +176,8 @@ ovsdb_idl_create(const char *remote, const struct ovsdb_idl_class *class)
shash_add_assert(&idl->table_by_name, tc->name, table);
table->class = tc;
table->modes = xmalloc(tc->n_columns);
memset(table->modes, OVSDB_IDL_MODE_RW, tc->n_columns);
memset(table->modes, default_mode, tc->n_columns);
table->need_table = false;
shash_init(&table->columns);
for (j = 0; j < tc->n_columns; j++) {
const struct ovsdb_idl_column *column = &tc->columns[j];
@@ -359,22 +376,84 @@ ovsdb_idl_force_reconnect(struct ovsdb_idl *idl)
{
jsonrpc_session_force_reconnect(idl->session);
}
static void
ovsdb_idl_set_mode(struct ovsdb_idl *idl,
const struct ovsdb_idl_column *column,
enum ovsdb_idl_mode mode)
static unsigned char *
ovsdb_idl_get_mode(struct ovsdb_idl *idl,
const struct ovsdb_idl_column *column)
{
size_t i;
assert(!idl->change_seqno);
for (i = 0; i < idl->class->n_tables; i++) {
const struct ovsdb_idl_table *table = &idl->tables[i];
const struct ovsdb_idl_table_class *tc = table->class;
if (column >= tc->columns && column < &tc->columns[tc->n_columns]) {
unsigned char *modep = &table->modes[column - tc->columns];
assert(*modep == OVSDB_IDL_MODE_RW || *modep == mode);
*modep = mode;
return &table->modes[column - tc->columns];
}
}
NOT_REACHED();
}
static void
add_ref_table(struct ovsdb_idl *idl, const struct ovsdb_base_type *base)
{
if (base->type == OVSDB_TYPE_UUID && base->u.uuid.refTableName) {
struct ovsdb_idl_table *table;
table = shash_find_data(&idl->table_by_name,
base->u.uuid.refTableName);
if (table) {
table->need_table = true;
} else {
VLOG_WARN("%s IDL class missing referenced table %s",
idl->class->database, base->u.uuid.refTableName);
}
}
}
/* Turns on OVSDB_IDL_MONITOR and OVSDB_IDL_ALERT for 'column' in 'idl'. Also
* ensures that any tables referenced by 'column' will be replicated, even if
* no columns in that table are selected for replication (see
* ovsdb_idl_add_table() for more information).
*
* This function is only useful if 'monitor_everything_by_default' was false in
* the call to ovsdb_idl_create(). This function should be called between
* ovsdb_idl_create() and the first call to ovsdb_idl_run().
*/
void
ovsdb_idl_add_column(struct ovsdb_idl *idl,
const struct ovsdb_idl_column *column)
{
*ovsdb_idl_get_mode(idl, column) = OVSDB_IDL_MONITOR | OVSDB_IDL_ALERT;
add_ref_table(idl, &column->type.key);
add_ref_table(idl, &column->type.value);
}
/* Ensures that the table with class 'tc' will be replicated on 'idl' even if
* no columns are selected for replication. This can be useful because it
* allows 'idl' to keep track of what rows in the table actually exist, which
* in turn allows columns that reference the table to have accurate contents.
* (The IDL presents the database with references to rows that do not exist
* removed.)
*
* This function is only useful if 'monitor_everything_by_default' was false in
* the call to ovsdb_idl_create(). This function should be called between
* ovsdb_idl_create() and the first call to ovsdb_idl_run().
*/
void
ovsdb_idl_add_table(struct ovsdb_idl *idl,
const struct ovsdb_idl_table_class *tc)
{
size_t i;
for (i = 0; i < idl->class->n_tables; i++) {
struct ovsdb_idl_table *table = &idl->tables[i];
if (table->class == tc) {
table->need_table = true;
return;
}
}
@@ -382,41 +461,28 @@ ovsdb_idl_set_mode(struct ovsdb_idl *idl,
NOT_REACHED();
}
/* By default, 'idl' replicates all of the columns in the remote database, and
* ovsdb_idl_run() returns true upon a change to any column in the database.
* Call this function to avoid alerting ovsdb_idl_run()'s caller upon changes
* to 'column'.
/* Turns off OVSDB_IDL_ALERT for 'column' in 'idl'.
*
* This is useful for columns that a client treats as "write-only", that is, it
* updates them but doesn't want to get alerted about its own updates. It also
* won't be alerted about other clients' updates, so this is suitable only for
* use by a client that "owns" a particular column.
*
* The client must be careful not to retain pointers to data in 'column' across
* calls to ovsdb_idl_run(), even when that function returns false, because
* the client is not alerted to changes.
*
* This function should be called after ovsdb_idl_create(), but before the
* first call to ovsdb_idl_run(). For any given column, this function may be
* called or ovsdb_idl_omit() may be called, but not both. */
* This function should be called between ovsdb_idl_create() and the first call
* to ovsdb_idl_run().
*/
void
ovsdb_idl_set_write_only(struct ovsdb_idl *idl,
const struct ovsdb_idl_column *column)
ovsdb_idl_omit_alert(struct ovsdb_idl *idl,
const struct ovsdb_idl_column *column)
{
ovsdb_idl_set_mode(idl, column, OVSDB_IDL_MODE_WO);
*ovsdb_idl_get_mode(idl, column) &= ~OVSDB_IDL_ALERT;
}
/* By default, 'idl' replicates all of the columns in the remote database.
* Call this function to omit replicating 'column'. This saves CPU time and
* bandwidth to the database.
/* Sets the mode for 'column' in 'idl' to 0. See the big comment above
* OVSDB_IDL_MONITOR for details.
*
* This function should be called after ovsdb_idl_create(), but before the
* first call to ovsdb_idl_run(). For any given column, this function may be
* called or ovsdb_idl_set_write_only() may be called, but not both. */
* This function should be called between ovsdb_idl_create() and the first call
* to ovsdb_idl_run().
*/
void
ovsdb_idl_omit(struct ovsdb_idl *idl, const struct ovsdb_idl_column *column)
{
ovsdb_idl_set_mode(idl, column, OVSDB_IDL_MODE_NONE);
*ovsdb_idl_get_mode(idl, column) = 0;
}
static void
@@ -433,16 +499,22 @@ ovsdb_idl_send_monitor_request(struct ovsdb_idl *idl)
struct json *monitor_request, *columns;
size_t j;
monitor_request = json_object_create();
columns = json_array_create_empty();
columns = table->need_table ? json_array_create_empty() : NULL;
for (j = 0; j < tc->n_columns; j++) {
const struct ovsdb_idl_column *column = &tc->columns[j];
if (table->modes[j] != OVSDB_IDL_MODE_NONE) {
if (table->modes[j] & OVSDB_IDL_MONITOR) {
if (!columns) {
columns = json_array_create_empty();
}
json_array_add(columns, json_string_create(column->name));
}
}
json_object_put(monitor_request, "columns", columns);
json_object_put(monitor_requests, tc->name, monitor_request);
if (columns) {
monitor_request = json_object_create();
json_object_put(monitor_request, "columns", columns);
json_object_put(monitor_requests, tc->name, monitor_request);
}
}
json_destroy(idl->monitor_request_id);
@@ -642,7 +714,7 @@ ovsdb_idl_row_update(struct ovsdb_idl_row *row, const struct json *row_json)
if (!ovsdb_datum_equals(old, &datum, &column->type)) {
ovsdb_datum_swap(old, &datum);
if (table->modes[column_idx] == OVSDB_IDL_MODE_RW) {
if (table->modes[column_idx] & OVSDB_IDL_ALERT) {
changed = true;
}
} else {
@@ -1563,7 +1635,8 @@ ovsdb_idl_txn_write(const struct ovsdb_idl_row *row_,
assert(row->new != NULL);
assert(column_idx < class->n_columns);
assert(row->table->modes[column_idx] != OVSDB_IDL_MODE_NONE);
assert(row->old == NULL ||
row->table->modes[column_idx] & OVSDB_IDL_MONITOR);
if (hmap_node_is_null(&row->txn_node)) {
hmap_insert(&row->table->idl->txn->txn_rows, &row->txn_node,