From 3f0678c1e368e5236a538fb5ea817f5f0adae79a Mon Sep 17 00:00:00 2001 From: Sebastian Harl Date: Sun, 17 Aug 2008 14:11:13 +0200 Subject: [PATCH] postgresql plugin: Added support for protocol versions less than 3. Support for passing parameters to a query was added in protocol version 3 which was introduced in version 7.4 of PostgreSQL (later version still support earlier protocol versions though). If that is not available, we now fall back to PQexec() if no parameters have been specified. Else, we skip the query and report an error. Signed-off-by: Sebastian Harl Signed-off-by: Florian Forster --- src/collectd.conf.pod | 3 +++ src/postgresql.c | 65 ++++++++++++++++++++++++++++++++++++++++----------- 2 files changed, 54 insertions(+), 14 deletions(-) diff --git a/src/collectd.conf.pod b/src/collectd.conf.pod index 1e71badb..5a1ced2b 100644 --- a/src/collectd.conf.pod +++ b/src/collectd.conf.pod @@ -1078,6 +1078,9 @@ The username used to connect to the database. =back +Please note that parameters are only supported by PostgreSQL's protocol +version 3 and above which was introduced in version 7.4 of PostgreSQL. + =item B I [I] Specify the I and optional I used to dispatch the value diff --git a/src/postgresql.c b/src/postgresql.c index eb7587ff..fbc117b0 100644 --- a/src/postgresql.c +++ b/src/postgresql.c @@ -103,6 +103,8 @@ typedef struct { PGconn *conn; c_complain_t conn_complaint; + int proto_version; + int max_params_num; /* user configuration */ @@ -209,6 +211,8 @@ static c_psql_database_t *c_psql_database_new (const char *name) db->conn_complaint.last = 0; db->conn_complaint.interval = 0; + db->proto_version = 0; + db->max_params_num = 0; db->queries = NULL; @@ -323,6 +327,11 @@ static int c_psql_check_connection (c_psql_database_t *db) db->database, PQerrorMessage (db->conn)); return -1; } + + db->proto_version = PQprotocolVersion (db->conn); + if (3 > db->proto_version) + log_warn ("Protocol version %d does not support parameters.", + db->proto_version); } c_release (LOG_INFO, &db->conn_complaint, @@ -330,20 +339,11 @@ static int c_psql_check_connection (c_psql_database_t *db) return 0; } /* c_psql_check_connection */ -static int c_psql_exec_query (c_psql_database_t *db, int idx) +static PGresult *c_psql_exec_query_params (c_psql_database_t *db, + c_psql_query_t *query) { - c_psql_query_t *query; - PGresult *res; - char *params[db->max_params_num]; - - int rows, cols; - int i; - - if (idx >= db->queries_num) - return -1; - - query = db->queries[idx]; + int i; assert (db->max_params_num >= query->params_num); @@ -364,9 +364,40 @@ static int c_psql_exec_query (c_psql_database_t *db, int idx) } } - res = PQexecParams (db->conn, query->query, query->params_num, NULL, + return PQexecParams (db->conn, query->query, query->params_num, NULL, (const char *const *)((0 == query->params_num) ? NULL : params), NULL, NULL, /* return text data */ 0); +} /* c_psql_exec_query_params */ + +static PGresult *c_psql_exec_query_noparams (c_psql_database_t *db, + c_psql_query_t *query) +{ + return PQexec (db->conn, query->query); +} /* c_psql_exec_query_noparams */ + +static int c_psql_exec_query (c_psql_database_t *db, int idx) +{ + c_psql_query_t *query; + PGresult *res; + + int rows, cols; + int i; + + if (idx >= db->queries_num) + return -1; + + query = db->queries[idx]; + + if (3 <= db->proto_version) + res = c_psql_exec_query_params (db, query); + else if (0 == query->params_num) + res = c_psql_exec_query_noparams (db, query); + else { + log_err ("Connection to database \"%s\" does not support parameters " + "(protocol version %d) - cannot execute query \"%s\".", + db->database, db->proto_version, query->name); + return -1; + } if (PGRES_TUPLES_OK != PQresultStatus (res)) { log_err ("Failed to execute SQL query: %s", @@ -522,6 +553,8 @@ static int c_psql_init (void) if (0 != c_psql_check_connection (db)) continue; + db->proto_version = PQprotocolVersion (db->conn); + server_host = PQhost (db->conn); server_version = PQserverVersion (db->conn); log_info ("Sucessfully connected to database %s (user %s) " @@ -530,7 +563,11 @@ static int c_psql_init (void) PQdb (db->conn), PQuser (db->conn), C_PSQL_SOCKET3 (server_host, PQport (db->conn)), C_PSQL_SERVER_VERSION3 (server_version), - PQprotocolVersion (db->conn), PQbackendPID (db->conn)); + db->proto_version, PQbackendPID (db->conn)); + + if (3 > db->proto_version) + log_warn ("Protocol version %d does not support parameters.", + db->proto_version); } plugin_register_read ("postgresql", c_psql_read); -- 2.11.0