Removed timer to delete contacts from db, as this is not supported from p_usrloc.

As documented, the deletion of expired contacts must be done externally
Also, because of the particularities of p_usrloc, only DB_ONLY mode is supported.
(other modes are too centralized and can't scale)

modules_k/p_usrloc/README

@@ -607,19 +607,8 @@ modparam("p_usrloc", "default_db_url", "mysql://ser:ser@localhost/ser")
 5.1. db_mode (integer)
 
    The p_usrloc module must utilize database for persistent contact
-   storage. So mode 0 makes no sense in this setup.
-     * 1 - Write-Through scheme. All changes to usrloc are immediately
-       reflected in database too. This is very slow, but very reliable.
-       Use this scheme if speed is not your priority but need to make sure
-       that no registered contacts will be lost during crash or reboot.
-     * 2 - Write-Back scheme. This is a combination of previous two
-       schemes. All changes are made to memory and database
-       synchronization is done in the timer. The timer deletes all expired
-       contacts and flushes all modified or new contacts to database. Use
-       this scheme if you encounter high-load peaks and want them to
-       process as fast as possible. The mode will not help at all if the
-       load is high all the time. Also, latency of this mode is much lower
-       than latency of mode 1, but slightly higher than latency of mode 0.
+   storage. Only mode 3 is possible at this time. Because of the way other
+   matching mode work, they make no sense on a distributed environment.
      * 3 - DB-Only scheme. No memory cache is kept, all operations being
        directly performed with the database. The timer deletes all expired
        contacts from database - cleans after clients that didn't

modules_k/p_usrloc/doc/p_usrloc_user.xml

@@ -609,31 +609,10 @@ modparam("p_usrloc", "default_db_url", "mysql://ser:ser@localhost/ser")
 	<title><varname>db_mode</varname> (integer)</title>
 		<para>
 		The p_usrloc module must utilize database for persistent contact storage.
-		So mode 0 makes no sense in this setup.
+		Only mode 3 is possible at this time. Because of the way other matching mode work,
+		they make no sense on a distributed environment.
 		</para>
 		<itemizedlist>
-		<listitem>
-			<para>
-			1 - Write-Through scheme. All changes to usrloc are immediately
-			reflected in database too. This is very slow, but very reliable.
-			Use this scheme if speed is not your priority but need to make
-			sure that no registered contacts will be lost during crash or
-			reboot.
-			</para>
-		</listitem>
-		<listitem>
-			<para>
-			2 - Write-Back scheme. This is a combination of previous two
-			schemes. All changes are made to memory and database
-			synchronization is done in the timer. The timer deletes all
-			expired contacts and flushes all modified or new contacts to
-			database.  Use this scheme if you encounter high-load peaks
-			and want them to process as fast as possible. The mode will
-			not help at all if the load is high all the time.  Also, latency
-			of this mode is much lower than latency of mode 1, but slightly
-			higher than latency of mode 0.
-			</para>
-		</listitem>
 		<listitem>
 			<para>
 			3 - DB-Only scheme. No memory cache is kept, all operations being

modules_k/p_usrloc/p_usrloc_mod.c

@@ -57,7 +57,6 @@
 #include "../../sr_module.h"
 #include "../../dprint.h"
 #include "../../rpc_lookup.h"
-#include "../../timer.h"     /* register_timer */
 #include "../../globals.h"   /* is_main */
 #include "../../ut.h"        /* str_init */
 #include "udomain.h"         /* {insert,delete,get,release}_urecord */
@@ -92,7 +91,6 @@ MODULE_VERSION
 
 static int mod_init(void);                          /*!< Module initialization function */
 static void destroy(void);                          /*!< Module destroy function */
-static void timer(unsigned int ticks, void* param); /*!< Timer handler */
 static int child_init(int rank);                    /*!< Per-child init function */
 static int mi_child_init(void);
 static int mi_child_loc_nr_init(void);
@@ -151,7 +149,6 @@ str path_col        = str_init(PATH_COL);		/*!< Name of column containing the Pa
 str sock_col        = str_init(SOCK_COL);		/*!< Name of column containing the received socket */
 str methods_col     = str_init(METHODS_COL);		/*!< Name of column containing the supported methods */
 str last_mod_col     = str_init(LAST_MOD_COL);		/*!< Name of column containing the last modified date */
-int timer_interval  = 60;				/*!< Timer interval in seconds */
 int db_mode         = 3;				/*!< Database sync scheme:  1-write through, 2-write back, 3-only db */
 int use_domain      = 0;				/*!< Whether usrloc should use domain part of aor */
 int desc_time_order = 0;				/*!< By default do not enable timestamp ordering */
@@ -218,7 +215,6 @@ static param_export_t params[] = {
 	{"cseq_column",       STR_PARAM, &cseq_col.s      },
 	{"flags_column",      STR_PARAM, &flags_col.s     },
 	{"cflags_column",     STR_PARAM, &cflags_col.s    },
-	{"timer_interval",    INT_PARAM, &timer_interval  },
 	{"db_mode",           INT_PARAM, &db_mode         },
 	{"use_domain",        INT_PARAM, &use_domain      },
 	{"desc_time_order",   INT_PARAM, &desc_time_order },
@@ -374,24 +370,17 @@ static int mod_init(void)
 		return -1;
 	}
 
-	/* Register cache timer */
-	register_timer( timer, 0, timer_interval);
-
 	/* init the callbacks list */
 	if ( init_ulcb_list() < 0) {
 		LM_ERR("usrloc/callbacks initialization failed\n");
 		return -1;
 	}
 
-	if (db_mode == NO_DB) {
-		LM_ERR("No database was configured! Partioned user location is useless!");
+	if (db_mode != DB_ONLY) {
+		LM_ERR("DB_ONLY is the only mode possible for partitioned usrloc. Please set db_mode to 3");
 		return  -1;
 	}
 
-	if (db_mode == WRITE_BACK) {
-		LM_WARN("The WRITE BACK mode will create discrepancies between memory and db backend");
-	}
-
 	/* Shall we use database ? */
 	if (db_mode != NO_DB) { /* Yes */
 		if(!default_db_url.s || !strlen(default_db_url.s)){
@@ -481,9 +470,6 @@ static void destroy(void)
 {
 	/* we need to sync DB in order to flush the cache */
 	ul_unlock_locks();
-	if (synchronize_all_udomains() != 0) {
-		LM_ERR("flushing cache failed\n");
-	}
 
 	free_all_udomains();
 	ul_destroy_locks();
@@ -497,16 +483,6 @@ static void destroy(void)
 }
 
 
-/*! \brief
- * Timer handler
- */
-static void timer(unsigned int ticks, void* param)
-{
-	if (synchronize_all_udomains() != 0) {
-		LM_ERR("synchronizing cache failed\n");
-	}
-}
-
 static int mi_child_loc_nr_init(void)
 {
 	if(ul_db_child_locnr_init() < 0){

modules_k/p_usrloc/p_usrloc_mod.h

@@ -87,7 +87,6 @@ extern str sock_col;
 extern str methods_col;
 extern str last_mod_col;
 
-extern int timer_interval;
 extern int db_mode;
 extern int use_domain;
 extern int desc_time_order;