X-Git-Url: http://git.onelab.eu/?a=blobdiff_plain;f=ovsdb%2Fjsonrpc-server.c;h=febc351dd84caec7200af4bf0404c9771dc0d544;hb=485e2766d816a18e1a51ddf5e12e55f38aeedf89;hp=88656b9656f0f62a8a6a59101275755235d5f36a;hpb=f1936eb65178f796d26a8d265697af8c19dce8cd;p=sliver-openvswitch.git diff --git a/ovsdb/jsonrpc-server.c b/ovsdb/jsonrpc-server.c index 88656b965..febc351dd 100644 --- a/ovsdb/jsonrpc-server.c +++ b/ovsdb/jsonrpc-server.c @@ -1,4 +1,4 @@ -/* Copyright (c) 2009, 2010, 2011, 2012 Nicira Networks +/* Copyright (c) 2009, 2010, 2011, 2012, 2013 Nicira, Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. @@ -17,7 +17,6 @@ #include "jsonrpc-server.h" -#include #include #include "bitmap.h" @@ -31,6 +30,7 @@ #include "reconnect.h" #include "row.h" #include "server.h" +#include "simap.h" #include "stream.h" #include "table.h" #include "timeval.h" @@ -51,6 +51,8 @@ static struct ovsdb_jsonrpc_session *ovsdb_jsonrpc_session_create( struct ovsdb_jsonrpc_remote *, struct jsonrpc_session *); static void ovsdb_jsonrpc_session_run_all(struct ovsdb_jsonrpc_remote *); static void ovsdb_jsonrpc_session_wait_all(struct ovsdb_jsonrpc_remote *); +static void ovsdb_jsonrpc_session_get_memory_usage_all( + const struct ovsdb_jsonrpc_remote *, struct simap *usage); static void ovsdb_jsonrpc_session_close_all(struct ovsdb_jsonrpc_remote *); static void ovsdb_jsonrpc_session_reconnect_all(struct ovsdb_jsonrpc_remote *); static void ovsdb_jsonrpc_session_set_all_options( @@ -63,6 +65,7 @@ static void ovsdb_jsonrpc_session_unlock__(struct ovsdb_lock_waiter *); /* Triggers. */ static void ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *, + struct ovsdb *, struct json *id, struct json *params); static struct ovsdb_jsonrpc_trigger *ovsdb_jsonrpc_trigger_find( struct ovsdb_jsonrpc_session *, const struct json *id, size_t hash); @@ -73,12 +76,14 @@ static void ovsdb_jsonrpc_trigger_complete_done( /* Monitors. */ static struct json *ovsdb_jsonrpc_monitor_create( - struct ovsdb_jsonrpc_session *, struct json *params); + struct ovsdb_jsonrpc_session *, struct ovsdb *, struct json *params); static struct jsonrpc_msg *ovsdb_jsonrpc_monitor_cancel( struct ovsdb_jsonrpc_session *, struct json_array *params, const struct json *request_id); static void ovsdb_jsonrpc_monitor_remove_all(struct ovsdb_jsonrpc_session *); +static size_t ovsdb_jsonrpc_monitor_json_length_all( + struct ovsdb_jsonrpc_session *); /* JSON-RPC database server. */ @@ -95,6 +100,7 @@ struct ovsdb_jsonrpc_remote { struct ovsdb_jsonrpc_server *server; struct pstream *listener; /* Listener, if passive. */ struct list sessions; /* List of "struct ovsdb_jsonrpc_session"s. */ + uint8_t dscp; }; static struct ovsdb_jsonrpc_remote *ovsdb_jsonrpc_server_add_remote( @@ -103,16 +109,29 @@ static struct ovsdb_jsonrpc_remote *ovsdb_jsonrpc_server_add_remote( ); static void ovsdb_jsonrpc_server_del_remote(struct shash_node *); +/* Creates and returns a new server to provide JSON-RPC access to an OVSDB. + * + * The caller must call ovsdb_jsonrpc_server_add_db() for each database to + * which 'server' should provide access. */ struct ovsdb_jsonrpc_server * -ovsdb_jsonrpc_server_create(struct ovsdb *db) +ovsdb_jsonrpc_server_create(void) { struct ovsdb_jsonrpc_server *server = xzalloc(sizeof *server); - ovsdb_server_init(&server->up, db); + ovsdb_server_init(&server->up); server->max_sessions = 64; shash_init(&server->remotes); return server; } +/* Adds 'db' to the set of databases served out by 'svr'. Returns true if + * successful, false if 'db''s name is the same as some database already in + * 'server'. */ +bool +ovsdb_jsonrpc_server_add_db(struct ovsdb_jsonrpc_server *svr, struct ovsdb *db) +{ + return ovsdb_server_add_db(&svr->up, db); +} + void ovsdb_jsonrpc_server_destroy(struct ovsdb_jsonrpc_server *svr) { @@ -189,10 +208,11 @@ ovsdb_jsonrpc_server_add_remote(struct ovsdb_jsonrpc_server *svr, remote->server = svr; remote->listener = listener; list_init(&remote->sessions); + remote->dscp = options->dscp; shash_add(&svr->remotes, name, remote); if (!listener) { - ovsdb_jsonrpc_session_create(remote, jsonrpc_session_open(name)); + ovsdb_jsonrpc_session_create(remote, jsonrpc_session_open(name, true)); } return remote; } @@ -265,7 +285,8 @@ ovsdb_jsonrpc_server_run(struct ovsdb_jsonrpc_server *svr) error = pstream_accept(remote->listener, &stream); if (!error) { struct jsonrpc_session *js; - js = jsonrpc_session_open_unreliably(jsonrpc_open(stream)); + js = jsonrpc_session_open_unreliably(jsonrpc_open(stream), + remote->dscp); ovsdb_jsonrpc_session_create(remote, js); } else if (error != EAGAIN) { VLOG_WARN_RL(&rl, "%s: accept failed: %s", @@ -293,6 +314,22 @@ ovsdb_jsonrpc_server_wait(struct ovsdb_jsonrpc_server *svr) ovsdb_jsonrpc_session_wait_all(remote); } } + +/* Adds some memory usage statistics for 'svr' into 'usage', for use with + * memory_report(). */ +void +ovsdb_jsonrpc_server_get_memory_usage(const struct ovsdb_jsonrpc_server *svr, + struct simap *usage) +{ + struct shash_node *node; + + simap_increase(usage, "sessions", svr->n_sessions); + SHASH_FOR_EACH (node, &svr->remotes) { + struct ovsdb_jsonrpc_remote *remote = node->data; + + ovsdb_jsonrpc_session_get_memory_usage_all(remote, usage); + } +} /* JSON-RPC database server session. */ @@ -300,6 +337,8 @@ struct ovsdb_jsonrpc_session { struct list node; /* Element in remote's sessions list. */ struct ovsdb_session up; struct ovsdb_jsonrpc_remote *remote; + size_t backlog_threshold; /* See ovsdb_jsonrpc_session_run(). */ + size_t reply_backlog; /* Triggers. */ struct hmap triggers; /* Hmap of "struct ovsdb_jsonrpc_trigger"s. */ @@ -315,6 +354,8 @@ struct ovsdb_jsonrpc_session { static void ovsdb_jsonrpc_session_close(struct ovsdb_jsonrpc_session *); static int ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *); static void ovsdb_jsonrpc_session_wait(struct ovsdb_jsonrpc_session *); +static void ovsdb_jsonrpc_session_get_memory_usage( + const struct ovsdb_jsonrpc_session *, struct simap *usage); static void ovsdb_jsonrpc_session_set_options( struct ovsdb_jsonrpc_session *, const struct ovsdb_jsonrpc_options *); static void ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *, @@ -329,11 +370,13 @@ ovsdb_jsonrpc_session_create(struct ovsdb_jsonrpc_remote *remote, struct ovsdb_jsonrpc_session *s; s = xzalloc(sizeof *s); - ovsdb_session_init(&s->up, remote->server->up.db); + ovsdb_session_init(&s->up, &remote->server->up); s->remote = remote; list_push_back(&remote->sessions, &s->node); hmap_init(&s->triggers); hmap_init(&s->monitors); + s->reply_backlog = 0; + s->backlog_threshold = 1024 * 1024; s->js = js; s->js_seqno = jsonrpc_session_get_seqno(js); @@ -347,9 +390,13 @@ ovsdb_jsonrpc_session_close(struct ovsdb_jsonrpc_session *s) { ovsdb_jsonrpc_monitor_remove_all(s); ovsdb_jsonrpc_session_unlock_all(s); + ovsdb_jsonrpc_trigger_complete_all(s); + + hmap_destroy(&s->monitors); + hmap_destroy(&s->triggers); + jsonrpc_session_close(s->js); list_remove(&s->node); - ovsdb_session_destroy(&s->up); s->remote->server->n_sessions--; ovsdb_session_destroy(&s->up); free(s); @@ -358,6 +405,8 @@ ovsdb_jsonrpc_session_close(struct ovsdb_jsonrpc_session *s) static int ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *s) { + size_t backlog; + jsonrpc_session_run(s->js); if (s->js_seqno != jsonrpc_session_get_seqno(s->js)) { s->js_seqno = jsonrpc_session_get_seqno(s->js); @@ -368,7 +417,8 @@ ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *s) ovsdb_jsonrpc_trigger_complete_done(s); - if (!jsonrpc_session_get_backlog(s->js)) { + backlog = jsonrpc_session_get_backlog(s->js); + if (!backlog) { struct jsonrpc_msg *msg = jsonrpc_session_recv(s->js); if (msg) { if (msg->type == JSONRPC_REQUEST) { @@ -383,6 +433,39 @@ ovsdb_jsonrpc_session_run(struct ovsdb_jsonrpc_session *s) jsonrpc_msg_destroy(msg); } } + s->reply_backlog = jsonrpc_session_get_backlog(s->js); + } else if (backlog > s->reply_backlog + s->backlog_threshold) { + /* We have a lot of data queued to send to the client. The data is + * likely to be mostly monitor updates. It is unlikely that the + * monitor updates are due to transactions by 's', because we will not + * let 's' make any more transactions until it drains its backlog to 0 + * (see previous 'if' case). So the monitor updates are probably due + * to transactions made by database clients other than 's'. We can't + * fix that by preventing 's' from executing more transactions. We + * could fix it by preventing every client from executing transactions, + * but then one slow or hung client could prevent other clients from + * doing useful work. + * + * Our solution is to cap the maximum backlog to O(1) in the amount of + * data in the database. If the backlog exceeds that amount, then we + * disconnect the client. When it reconnects, it can fetch the entire + * contents of the database using less data than was previously + * backlogged. */ + size_t monitor_length; + + monitor_length = ovsdb_jsonrpc_monitor_json_length_all(s); + if (backlog > s->reply_backlog + monitor_length * 2) { + VLOG_INFO("%s: %zu bytes backlogged but a complete replica " + "would only take %zu bytes, disconnecting", + jsonrpc_session_get_name(s->js), + backlog - s->reply_backlog, monitor_length); + jsonrpc_session_force_reconnect(s->js); + } else { + /* The backlog is not unreasonably big. Only check again after it + * becomes much bigger. */ + s->backlog_threshold = 2 * MAX(s->backlog_threshold * 2, + monitor_length); + } } return jsonrpc_session_is_alive(s->js) ? 0 : ETIMEDOUT; } @@ -428,6 +511,27 @@ ovsdb_jsonrpc_session_wait_all(struct ovsdb_jsonrpc_remote *remote) } } +static void +ovsdb_jsonrpc_session_get_memory_usage(const struct ovsdb_jsonrpc_session *s, + struct simap *usage) +{ + simap_increase(usage, "triggers", hmap_count(&s->triggers)); + simap_increase(usage, "monitors", hmap_count(&s->monitors)); + simap_increase(usage, "backlog", jsonrpc_session_get_backlog(s->js)); +} + +static void +ovsdb_jsonrpc_session_get_memory_usage_all( + const struct ovsdb_jsonrpc_remote *remote, + struct simap *usage) +{ + struct ovsdb_jsonrpc_session *s; + + LIST_FOR_EACH (s, node, &remote->sessions) { + ovsdb_jsonrpc_session_get_memory_usage(s, usage); + } +} + static void ovsdb_jsonrpc_session_close_all(struct ovsdb_jsonrpc_remote *remote) { @@ -462,6 +566,22 @@ ovsdb_jsonrpc_session_set_all_options( { struct ovsdb_jsonrpc_session *s; + if (remote->listener) { + int error; + + error = pstream_set_dscp(remote->listener, options->dscp); + if (error) { + VLOG_ERR("%s: set_dscp failed %s", + pstream_get_name(remote->listener), strerror(error)); + } else { + remote->dscp = options->dscp; + } + /* + * XXX race window between setting dscp to listening socket + * and accepting socket. Accepted socket may have old dscp value. + * Ignore this race window for now. + */ + } LIST_FOR_EACH (s, node, &remote->sessions) { ovsdb_jsonrpc_session_set_options(s, options); } @@ -516,21 +636,22 @@ ovsdb_jsonrpc_session_get_status(const struct ovsdb_jsonrpc_remote *remote, return true; } -static const char * -get_db_name(const struct ovsdb_jsonrpc_session *s) -{ - return s->remote->server->up.db->schema->name; -} - -static struct jsonrpc_msg * -ovsdb_jsonrpc_check_db_name(const struct ovsdb_jsonrpc_session *s, - const struct jsonrpc_msg *request) +/* Examines 'request' to determine the database to which it relates, and then + * searches 's' to find that database: + * + * - If successful, returns the database and sets '*replyp' to NULL. + * + * - If no such database exists, returns NULL and sets '*replyp' to an + * appropriate JSON-RPC error reply, owned by the caller. */ +static struct ovsdb * +ovsdb_jsonrpc_lookup_db(const struct ovsdb_jsonrpc_session *s, + const struct jsonrpc_msg *request, + struct jsonrpc_msg **replyp) { struct json_array *params; - const char *want_db_name; - const char *have_db_name; struct ovsdb_error *error; - struct jsonrpc_msg *reply; + const char *db_name; + struct ovsdb *db; params = json_array(request->params); if (!params->n || params->elems[0]->type != JSON_STRING) { @@ -540,22 +661,23 @@ ovsdb_jsonrpc_check_db_name(const struct ovsdb_jsonrpc_session *s, goto error; } - want_db_name = params->elems[0]->u.string; - have_db_name = get_db_name(s); - if (strcmp(want_db_name, have_db_name)) { + db_name = params->elems[0]->u.string; + db = shash_find_data(&s->up.server->dbs, db_name); + if (!db) { error = ovsdb_syntax_error( request->params, "unknown database", "%s request specifies unknown database %s", - request->method, want_db_name); + request->method, db_name); goto error; } - return NULL; + *replyp = NULL; + return db; error: - reply = jsonrpc_create_reply(ovsdb_error_to_json(error), request->id); + *replyp = jsonrpc_create_reply(ovsdb_error_to_json(error), request->id); ovsdb_error_destroy(error); - return reply; + return NULL; } static struct ovsdb_error * @@ -697,10 +819,10 @@ error: } static struct jsonrpc_msg * -execute_transaction(struct ovsdb_jsonrpc_session *s, +execute_transaction(struct ovsdb_jsonrpc_session *s, struct ovsdb *db, struct jsonrpc_msg *request) { - ovsdb_jsonrpc_trigger_create(s, request->id, request->params); + ovsdb_jsonrpc_trigger_create(s, db, request->id, request->params); request->id = NULL; request->params = NULL; jsonrpc_msg_destroy(request); @@ -714,30 +836,39 @@ ovsdb_jsonrpc_session_got_request(struct ovsdb_jsonrpc_session *s, struct jsonrpc_msg *reply; if (!strcmp(request->method, "transact")) { - reply = ovsdb_jsonrpc_check_db_name(s, request); + struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply); if (!reply) { - reply = execute_transaction(s, request); + reply = execute_transaction(s, db, request); } } else if (!strcmp(request->method, "monitor")) { - reply = ovsdb_jsonrpc_check_db_name(s, request); + struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply); if (!reply) { reply = jsonrpc_create_reply( - ovsdb_jsonrpc_monitor_create(s, request->params), request->id); + ovsdb_jsonrpc_monitor_create(s, db, request->params), + request->id); } } else if (!strcmp(request->method, "monitor_cancel")) { reply = ovsdb_jsonrpc_monitor_cancel(s, json_array(request->params), request->id); } else if (!strcmp(request->method, "get_schema")) { - reply = ovsdb_jsonrpc_check_db_name(s, request); + struct ovsdb *db = ovsdb_jsonrpc_lookup_db(s, request, &reply); if (!reply) { - reply = jsonrpc_create_reply( - ovsdb_schema_to_json(s->remote->server->up.db->schema), - request->id); + reply = jsonrpc_create_reply(ovsdb_schema_to_json(db->schema), + request->id); } } else if (!strcmp(request->method, "list_dbs")) { - reply = jsonrpc_create_reply( - json_array_create_1(json_string_create(get_db_name(s))), - request->id); + size_t n_dbs = shash_count(&s->up.server->dbs); + struct shash_node *node; + struct json **dbs; + size_t i; + + dbs = xmalloc(n_dbs * sizeof *dbs); + i = 0; + SHASH_FOR_EACH (node, &s->up.server->dbs) { + dbs[i++] = json_string_create(node->name); + } + reply = jsonrpc_create_reply(json_array_create(dbs, n_dbs), + request->id); } else if (!strcmp(request->method, "lock")) { reply = ovsdb_jsonrpc_session_lock(s, request, OVSDB_LOCK_WAIT); } else if (!strcmp(request->method, "steal")) { @@ -794,7 +925,7 @@ struct ovsdb_jsonrpc_trigger { }; static void -ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *s, +ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *s, struct ovsdb *db, struct json *id, struct json *params) { struct ovsdb_jsonrpc_trigger *t; @@ -816,7 +947,7 @@ ovsdb_jsonrpc_trigger_create(struct ovsdb_jsonrpc_session *s, /* Insert into trigger table. */ t = xmalloc(sizeof *t); - ovsdb_trigger_init(&s->up, &t->trigger, params, time_msec()); + ovsdb_trigger_init(&s->up, db, &t->trigger, params, time_msec()); t->id = id; hmap_insert(&s->triggers, &t->hmap_node, hash); @@ -920,6 +1051,7 @@ struct ovsdb_jsonrpc_monitor_table { struct ovsdb_jsonrpc_monitor { struct ovsdb_replica replica; struct ovsdb_jsonrpc_session *session; + struct ovsdb *db; struct hmap_node node; /* In ovsdb_jsonrpc_session's "monitors". */ struct json *monitor_id; @@ -933,6 +1065,8 @@ struct ovsdb_jsonrpc_monitor *ovsdb_jsonrpc_monitor_find( static void ovsdb_jsonrpc_monitor_destroy(struct ovsdb_replica *); static struct json *ovsdb_jsonrpc_monitor_get_initial( const struct ovsdb_jsonrpc_monitor *); +static size_t ovsdb_jsonrpc_monitor_json_length( + const struct ovsdb_jsonrpc_monitor *); static bool parse_bool(struct ovsdb_parser *parser, const char *name, bool default_value) @@ -1071,7 +1205,7 @@ ovsdb_jsonrpc_parse_monitor_request(struct ovsdb_jsonrpc_monitor_table *mt, } static struct json * -ovsdb_jsonrpc_monitor_create(struct ovsdb_jsonrpc_session *s, +ovsdb_jsonrpc_monitor_create(struct ovsdb_jsonrpc_session *s, struct ovsdb *db, struct json *params) { struct ovsdb_jsonrpc_monitor *m = NULL; @@ -1099,8 +1233,9 @@ ovsdb_jsonrpc_monitor_create(struct ovsdb_jsonrpc_session *s, m = xzalloc(sizeof *m); ovsdb_replica_init(&m->replica, &ovsdb_jsonrpc_replica_class); - ovsdb_add_replica(s->remote->server->up.db, &m->replica); + ovsdb_add_replica(db, &m->replica); m->session = s; + m->db = db; hmap_insert(&s->monitors, &m->node, json_hash(monitor_id, 0)); m->monitor_id = json_clone(monitor_id); shash_init(&m->tables); @@ -1112,7 +1247,7 @@ ovsdb_jsonrpc_monitor_create(struct ovsdb_jsonrpc_session *s, const struct json *mr_value; size_t i; - table = ovsdb_get_table(s->remote->server->up.db, node->name); + table = ovsdb_get_table(m->db, node->name); if (!table) { error = ovsdb_syntax_error(NULL, NULL, "no table named %s", node->name); @@ -1161,7 +1296,7 @@ ovsdb_jsonrpc_monitor_create(struct ovsdb_jsonrpc_session *s, error: if (m) { - ovsdb_remove_replica(s->remote->server->up.db, &m->replica); + ovsdb_remove_replica(m->db, &m->replica); } json = ovsdb_error_to_json(error); @@ -1185,7 +1320,7 @@ ovsdb_jsonrpc_monitor_cancel(struct ovsdb_jsonrpc_session *s, return jsonrpc_create_error(json_string_create("unknown monitor"), request_id); } else { - ovsdb_remove_replica(s->remote->server->up.db, &m->replica); + ovsdb_remove_replica(m->db, &m->replica); return jsonrpc_create_reply(json_object_create(), request_id); } } @@ -1197,14 +1332,30 @@ ovsdb_jsonrpc_monitor_remove_all(struct ovsdb_jsonrpc_session *s) struct ovsdb_jsonrpc_monitor *m, *next; HMAP_FOR_EACH_SAFE (m, next, node, &s->monitors) { - ovsdb_remove_replica(s->remote->server->up.db, &m->replica); + ovsdb_remove_replica(m->db, &m->replica); + } +} + +/* Returns an overestimate of the number of bytes of JSON data required to + * report the current contents of the database over all the monitors currently + * configured in 's'. */ +static size_t +ovsdb_jsonrpc_monitor_json_length_all(struct ovsdb_jsonrpc_session *s) +{ + struct ovsdb_jsonrpc_monitor *m; + size_t length; + + length = 0; + HMAP_FOR_EACH (m, node, &s->monitors) { + length += ovsdb_jsonrpc_monitor_json_length(m); } + return length; } static struct ovsdb_jsonrpc_monitor * ovsdb_jsonrpc_monitor_cast(struct ovsdb_replica *replica) { - assert(replica->class == &ovsdb_jsonrpc_replica_class); + ovs_assert(replica->class == &ovsdb_jsonrpc_replica_class); return CONTAINER_OF(replica, struct ovsdb_jsonrpc_monitor, replica); } @@ -1336,6 +1487,52 @@ ovsdb_jsonrpc_monitor_change_cb(const struct ovsdb_row *old, return true; } +/* Returns an overestimate of the number of bytes of JSON data required to + * report the current contents of the database over monitor 'm'. */ +static size_t +ovsdb_jsonrpc_monitor_json_length(const struct ovsdb_jsonrpc_monitor *m) +{ + const struct shash_node *node; + size_t length; + + /* Top-level overhead of monitor JSON. */ + length = 256; + + SHASH_FOR_EACH (node, &m->tables) { + const struct ovsdb_jsonrpc_monitor_table *mt = node->data; + const struct ovsdb_table *table = mt->table; + const struct ovsdb_row *row; + size_t i; + + /* Per-table JSON overhead: "":{...}. */ + length += strlen(table->schema->name) + 32; + + /* Per-row JSON overhead: ,"":{"old":{...},"new":{...}} */ + length += hmap_count(&table->rows) * (UUID_LEN + 32); + + /* Per-row, per-column JSON overhead: ,"": */ + for (i = 0; i < mt->n_columns; i++) { + const struct ovsdb_jsonrpc_monitor_column *c = &mt->columns[i]; + const struct ovsdb_column *column = c->column; + + length += hmap_count(&table->rows) * (8 + strlen(column->name)); + } + + /* Data. */ + HMAP_FOR_EACH (row, hmap_node, &table->rows) { + for (i = 0; i < mt->n_columns; i++) { + const struct ovsdb_jsonrpc_monitor_column *c = &mt->columns[i]; + const struct ovsdb_column *column = c->column; + + length += ovsdb_datum_json_length(&row->fields[column->index], + &column->type); + } + } + } + + return length; +} + static void ovsdb_jsonrpc_monitor_init_aux(struct ovsdb_jsonrpc_monitor_aux *aux, const struct ovsdb_jsonrpc_monitor *m,