Allow an UAcontext to have two database connections.

For some operations we want to use a private database connection as they
are either long running or may interfere with each other. We now keep
track of the normal shared database connection and a private database
connection used for these kind of operations that can run over a
dedicated database connection without leading to synchronization
problems in the data. Things like BVFS, restore, prune, purge etc can
all use this private database connection so they no longer block others
and for restore also don't lead to race conditions. These connections
we keep lingering until a close_db() call is done on the UA.

src/dird/protos.h

@@ -236,9 +236,8 @@ bool acl_access_ok(UAContext *ua, int acl, const char *item, int len);
 bool do_a_command(UAContext *ua);
 bool do_a_dot_command(UAContext *ua);
 int qmessages_cmd(UAContext *ua, const char *cmd);
-bool open_new_client_db(UAContext *ua);
-bool open_client_db(UAContext *ua, bool need_private = false);
-bool open_db(UAContext *ua, bool need_private = false);
+bool open_client_db(UAContext *ua, bool use_private = false);
+bool open_db(UAContext *ua, bool use_private = false);
 void close_db(UAContext *ua);
 int create_pool(JCR *jcr, B_DB *db, POOLRES *pool, e_pool_op op);
 void set_pool_dbr_defaults_in_media_dbr(MEDIA_DBR *mr, POOL_DBR *pr);

src/dird/ua.h

@@ -37,6 +37,8 @@ class UAContext {
    BSOCK *sd;
    JCR *jcr;
    B_DB *db;
+   B_DB *shared_db;                   /* Shared database connection used by multiple ua's */
+   B_DB *private_db;                  /* Private database connection only used by this ua */
    CATRES *catalog;
    CONRES *cons;                      /* Console resource */
    POOLMEM *cmd;                      /* Return command/name buffer */

src/dird/ua_cmds.c

@@ -1617,7 +1617,7 @@ static int delete_cmd(UAContext *ua, const char *cmd)
       NULL
    };
 
-   if (!open_client_db(ua)) {
+   if (!open_client_db(ua, true)) {
       return 1;
    }
 
@@ -2285,19 +2285,6 @@ static int version_cmd(UAContext *ua, const char *cmd)
 }
 #endif
 
-/*
- * This call uses open_client_db() and force a
- * new private connection to the catalog
- */
-bool open_new_client_db(UAContext *ua)
-{
-   /*
-    * Force a new private connection
-    */
-   close_db(ua);
-   return open_client_db(ua, true);
-}
-
 /*
  * This call explicitly checks for a catalog=catalog-name and
  *  if given, opens that catalog.  It also checks for
@@ -2306,7 +2293,7 @@ bool open_new_client_db(UAContext *ua)
  *  have a catalog, look for a Job keyword and get the
  *  catalog from its client record.
  */
-bool open_client_db(UAContext *ua, bool need_private)
+bool open_client_db(UAContext *ua, bool use_private)
 {
    int i;
    CATRES *catalog;
@@ -2326,7 +2313,7 @@ bool open_client_db(UAContext *ua, bool need_private)
             close_db(ua);
          }
          ua->catalog = catalog;
-         return open_db(ua, need_private);
+         return open_db(ua, use_private);
       }
    }
 
@@ -2348,7 +2335,7 @@ bool open_client_db(UAContext *ua, bool need_private)
             return false;
          }
          ua->catalog = catalog;
-         return open_db(ua, need_private);
+         return open_db(ua, use_private);
       }
    }
 
@@ -2370,23 +2357,37 @@ bool open_client_db(UAContext *ua, bool need_private)
             return false;
          }
          ua->catalog = catalog;
-         return open_db(ua, need_private);
+         return open_db(ua, use_private);
       }
    }
 
-   return open_db(ua, need_private);
+   return open_db(ua, use_private);
 }
 
 /*
  * Open the catalog database.
  */
-bool open_db(UAContext *ua, bool need_private)
+bool open_db(UAContext *ua, bool use_private)
 {
    bool mult_db_conn;
 
-   if (ua->db) {
+   /*
+    * See if we need to do any work at all.
+    * Point the current used db e.g. ua->db to the correct database connection.
+    */
+   if (use_private) {
+      if (ua->private_db) {
+         ua->db = ua->private_db;
+         return true;
+      }
+   } else if (ua->shared_db) {
+      ua->db = ua->shared_db;
       return true;
    }
+
+   /*
+    * Select the right catalog to use.
+    */
    if (!ua->catalog) {
       ua->catalog = get_catalog_resource(ua);
       if (!ua->catalog) {
@@ -2399,7 +2400,7 @@ bool open_db(UAContext *ua, bool need_private)
     * Some modules like bvfs need their own private catalog connection
     */
    mult_db_conn = ua->catalog->mult_db_connections;
-   if (need_private) {
+   if (use_private) {
       mult_db_conn = true;
    }
 
@@ -2415,26 +2416,43 @@ bool open_db(UAContext *ua, bool need_private)
                                          ua->catalog->db_socket,
                                          mult_db_conn,
                                          ua->catalog->disable_batch_insert,
-                                         need_private);
+                                         use_private);
    if (ua->db == NULL) {
       ua->error_msg(_("Could not open catalog database \"%s\".\n"), ua->catalog->db_name);
       return false;
    }
    ua->jcr->db = ua->db;
+
+   /*
+    * Save the new database connection under the right label e.g. shared or private.
+    */
+   if (use_private) {
+      ua->private_db = ua->db;
+   } else {
+      ua->shared_db = ua->db;
+   }
+
    if (!ua->api) {
       ua->send_msg(_("Using Catalog \"%s\"\n"), ua->catalog->name());
    }
+
    Dmsg1(150, "DB %s opened\n", ua->catalog->db_name);
    return true;
 }
 
 void close_db(UAContext *ua)
 {
-   if (ua->db) {
-      db_sql_close_pooled_connection(ua->jcr, ua->db);
-      ua->db = NULL;
-      if (ua->jcr) {
-         ua->jcr->db = NULL;
-      }
+   if (ua->jcr) {
+      ua->jcr->db = NULL;
+   }
+
+   if (ua->shared_db) {
+      db_sql_close_pooled_connection(ua->jcr, ua->shared_db);
+      ua->shared_db = NULL;
+   }
+
+   if (ua->private_db) {
+      db_sql_close_pooled_connection(ua->jcr, ua->private_db);
+      ua->private_db = NULL;
    }
 }