pgsql: If query failed because connection was lost, retry it automatically.

--HG--
branch : HEAD

diff --git a/src/lib-sql/driver-pgsql.c b/src/lib-sql/driver-pgsql.c
index 2d701508ab8c85cedeef63b2403dec0476235793..2018bf254768ddc683af76d131ff3f962a2e27eb 100644 (file)
--- a/src/lib-sql/driver-pgsql.c
+++ b/src/lib-sql/driver-pgsql.c
@@ -46,6 +46,7 @@ struct pgsql_result {
        struct sql_result api;
        PGresult *pgres;
 
+       char *query;
        unsigned int rownum, rows;
        unsigned int fields_count;
        const char **fields;
@@ -55,6 +56,8 @@ struct pgsql_result {
 
        sql_query_callback_t *callback;
        void *context;
+
+       unsigned int retry_query:1;
 };
 
 struct pgsql_queue {
@@ -80,6 +83,10 @@ struct pgsql_transaction_context {
 extern struct sql_db driver_pgsql_db;
 extern struct sql_result driver_pgsql_result;
 
+static void
+driver_pgsql_query_full(struct sql_db *db, const char *query,
+                       sql_query_callback_t *callback, void *context,
+                       bool retry_query);
 static void queue_send_next(struct pgsql_db *db);
 static void result_finish(struct pgsql_result *result);
 
@@ -280,6 +287,7 @@ static void driver_pgsql_result_free(struct sql_result *_result)
 
        i_free(result->fields);
        i_free(result->values);
+       i_free(result->query);
        i_free(result);
 
        if (db->queue != NULL && !db->querying && db->connected)
@@ -289,9 +297,15 @@ static void driver_pgsql_result_free(struct sql_result *_result)
 static void result_finish(struct pgsql_result *result)
 {
        struct pgsql_db *db = (struct pgsql_db *)result->api.db;
-       bool free_result = TRUE;
-
-       if (result->callback != NULL) {
+       bool free_result = TRUE, retry = FALSE;
+       bool disconnected;
+
+       disconnected = PQstatus(db->pg) == CONNECTION_BAD;
+       if (disconnected && result->pgres == NULL && result->retry_query) {
+               /* retry the query */
+               i_error("pgsql: Query failed, retrying: %s", last_error(db));
+               retry = TRUE;
+       } else if (result->callback != NULL) {
                result->api.callback = TRUE;
                T_BEGIN {
                        result->callback(&result->api, result->context);
@@ -299,13 +313,20 @@ static void result_finish(struct pgsql_result *result)
                result->api.callback = FALSE;
                free_result = db->sync_result != &result->api;
        }
-       if (free_result)
-               driver_pgsql_result_free(&result->api);
 
-       if (PQstatus(db->pg) == CONNECTION_BAD) {
+       if (disconnected) {
                /* disconnected */
                driver_pgsql_close(db);
+
+               if (retry) {
+                       /* retry the query */
+                       driver_pgsql_query_full(&db->api, result->query,
+                                               result->callback,
+                                               result->context, FALSE);
+               }
        }
+       if (free_result)
+               driver_pgsql_result_free(&result->api);
 }
 
 static void get_result(struct pgsql_result *result)
@@ -495,10 +516,10 @@ static void do_query(struct pgsql_result *result, const char *query)
        }
 }
 
-static void exec_callback(struct sql_result *result,
+static void exec_callback(struct sql_result *_result,
                          void *context ATTR_UNUSED)
 {
-        struct pgsql_db *db = (struct pgsql_db *)result->db;
+       struct pgsql_db *db = (struct pgsql_db *)_result->db;
 
        i_error("pgsql: sql_exec() failed: %s", last_error(db));
 }
@@ -525,7 +546,8 @@ driver_pgsql_escape_string(struct sql_db *_db, const char *string)
        return to;
 }
 
-static void driver_pgsql_exec(struct sql_db *db, const char *query)
+static void driver_pgsql_exec_full(struct sql_db *db, const char *query,
+                                  bool retry_query)
 {
        struct pgsql_result *result;
 
@@ -533,12 +555,22 @@ static void driver_pgsql_exec(struct sql_db *db, const char *query)
        result->api = driver_pgsql_result;
        result->api.db = db;
        result->callback = exec_callback;
-
+       if (retry_query) {
+               result->query = i_strdup(query);
+               result->retry_query = TRUE;
+       }
        do_query(result, query);
 }
 
-static void driver_pgsql_query(struct sql_db *db, const char *query,
-                              sql_query_callback_t *callback, void *context)
+static void driver_pgsql_exec(struct sql_db *db, const char *query)
+{
+       driver_pgsql_exec_full(db, query, TRUE);
+}
+
+static void
+driver_pgsql_query_full(struct sql_db *db, const char *query,
+                       sql_query_callback_t *callback, void *context,
+                       bool retry_query)
 {
        struct pgsql_result *result;
 
@@ -547,10 +579,19 @@ static void driver_pgsql_query(struct sql_db *db, const char *query,
        result->api.db = db;
        result->callback = callback;
        result->context = context;
-
+       if (retry_query) {
+               result->query = i_strdup(query);
+               result->retry_query = TRUE;
+       }
        do_query(result, query);
 }
 
+static void driver_pgsql_query(struct sql_db *db, const char *query,
+                              sql_query_callback_t *callback, void *context)
+{
+       driver_pgsql_query_full(db, query, callback, context, TRUE);
+}
+
 static void pgsql_query_s_callback(struct sql_result *result, void *context)
 {
         struct pgsql_db *db = context;
@@ -840,7 +881,8 @@ driver_pgsql_transaction_commit(struct sql_transaction_context *_ctx,
        ctx->callback = callback;
        ctx->context = context;
 
-       sql_query(_ctx->db, "COMMIT", transaction_commit_callback, ctx);
+       driver_pgsql_query_full(_ctx->db, "COMMIT",
+                               transaction_commit_callback, ctx, FALSE);
 }
 
 static int
@@ -884,9 +926,10 @@ driver_pgsql_transaction_rollback(struct sql_transaction_context *_ctx)
 }
 
 static void
-transaction_update_callback(struct sql_result *result,
-                           struct pgsql_transaction_context *ctx)
+transaction_update_callback(struct sql_result *result, void *context)
 {
+       struct pgsql_transaction_context *ctx = context;
+
        if (sql_result_next_row(result) < 0) {
                ctx->failed = TRUE;
                ctx->error = sql_result_get_error(result);
@@ -907,7 +950,8 @@ driver_pgsql_update(struct sql_transaction_context *_ctx, const char *query)
                sql_query(_ctx->db, "BEGIN", transaction_update_callback, ctx);
        }
 
-       sql_query(_ctx->db, query, transaction_update_callback, ctx);
+       driver_pgsql_query_full(_ctx->db, query,
+                               transaction_update_callback, ctx, FALSE);
 }
 
 struct sql_db driver_pgsql_db = {