docs for 'dns_zone_check_period'

diff --git a/README b/README
index c13028e98bf2c421388c697f90a202d86284a986..9f606994821f791499b491d667f356839c96909e 100644 (file)
--- a/README
+++ b/README
@@ -34,15 +34,21 @@ time instead just once at config load time.  This requires proper
 async DNS implementation.  Following list shows supported backends
 and their probing order:
 
-backend                    | parallel | EDNS0    | /etc/hosts | note
----------------------------+----------+----------+------------+------------------------
-udns                       | yes      | yes      | no         | ipv4-only
-evdns, libevent 2.x        | yes      | no       | yes        |
-getaddrinfo_a, glibc 2.9+  | yes      | yes (1)  | yes        | N/A on non-linux
-getaddrinfo, libc          | no       | yes (1)  | yes        | N/A on win32, requires pthreads
-evdns, libevent 1.x        | yes      | no       | no         | buggy
-
-(1) To enable EDNS0, add 'options edns0' to /etc/resolv.conf
+.DNS backends
+[options="header"]
+|===========================================================================================
+| backend                    | parallel | EDNS0 (1) | /etc/hosts | SOA lookup (2) | note
+
+| udns                       | yes      | yes       | no         | yes            | ipv4-only
+| evdns, libevent 2.x        | yes      | no        | yes        | no             |
+| getaddrinfo_a, glibc 2.9+  | yes      | yes (3)   | yes        | no             | N/A on non-linux
+| getaddrinfo, libc          | no       | yes (3)   | yes        | no             | N/A on win32, requires pthreads
+| evdns, libevent 1.x        | yes      | no        | no         | no             | buggy
+|===========================================================================================
+
+1. EDNS0 is required to have more then 8 addresses behind one hostname.
+2. SOA lookup is needed to re-check hostnames on zone serial change
+3. To enable EDNS0, add `options edns0` to /etc/resolv.conf
 
 `./configure` also has flags `--enable-evdns` and `--disable-evdns` which
 turn off automatic probing and force use of either `evdns` or `getaddrinfo_a()`.

diff --git a/doc/config.txt b/doc/config.txt
index 30c6a18aa80c741d20bb2791401a0754eba3df72..c24ff21b0afe520b95b7a1e3370c583d8090c30b 100644 (file)
--- a/doc/config.txt
+++ b/doc/config.txt
@@ -344,6 +344,20 @@ Actual DNS TTL is ignored.  [seconds]
 
 Default: 15
 
+==== dns_zone_check_period ====
+
+Period to check if zone serial has changed.
+
+PgBouncer can collect dns zones from hostnames (everything after first dot)
+and then periodically check if zone serial changes.
+If it notices changes, all hostnames under that zone
+are looked up again.  If any host ip changes, it's connections
+are invalidated.
+
+Works only with UDNS backend (`--with-udns` to configure).
+
+Default: 0 (disabled)
+
 === Dangerous timeouts ===
 
 Setting following timeouts cause unexpected errors.
@@ -374,8 +388,8 @@ Default: 0 (disabled)
 
 ==== idle_transaction_timeout ====
 
-If client has been in "idle in transaction" state longer, it will be disconnected.
-[seconds]
+If client has been in "idle in transaction" state longer,
+it will be disconnected.  [seconds]
 
 Default: 0 (disabled)
 

diff --git a/etc/pgbouncer.ini b/etc/pgbouncer.ini
index 82ea061fcdbd5dd641899bbb81455cdc0da9e3a3..4a57fb617bb803a45c9031c4d7aa43853eee4f70 100644 (file)
--- a/etc/pgbouncer.ini
+++ b/etc/pgbouncer.ini
@@ -213,3 +213,6 @@ default_pool_size = 20
 ;; DNS lookup caching time
 ;dns_max_ttl = 15
 
+;; DNS zone SOA lookup period
+;dns_zone_check_period = 0
+