Document WAL summarization information functions.

Commit 174c480508ac25568561443e6d4a82d5c1103487 added two new
information functions but failed to document them anywhere.

Discussion: http://postgr.es/m/CA+Tgmobvqqj-DW9F7uUzT-cQqs6wcVb-Xhs=w=hzJnXSE-kRGw@mail.gmail.com

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index cec21e42c05b139d36e220f1ed2bb883c7c99cb8..de78d58d4bc6d2bd6c69c4d059a3d060827e58ad 100644 (file)
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -26480,6 +26480,86 @@ SELECT collation for ('foo' COLLATE "de_DE");
 
   
 
+  
+   WAL Summarization Information Functions
+
+   
+    The functions shown in 
+    print information about the status of WAL summarization.
+    See .
+   
+
+   
+    WAL Summarization Information Functions
+    
+     
+      
+       
+        Function
+       
+       
+        Description
+       
+      
+     
+
+     
+      
+       
+        
+         pg_available_wal_summaries
+        
+        pg_available_wal_summaries ()
+        setof record
+        ( tli bigint,
+        start_lsn pg_lsn,
+        end_lsn pg_lsn )
+       
+       
+        Returns information about the WAL summary files present in the
+        data directory, under pg_wal/summaries.
+        One row will be returned per WAL summary file. Each file summarizes
+        WAL on the indicated TLI within the indicated LSN range. This function
+        might be useful to determine whether enough WAL summaries are present
+        on the server to take an incremental backup based on some prior
+        backup whose start LSN is known.
+       
+      
+
+      
+       
+        
+         pg_wal_summary_contents
+        
+        pg_wal_summary_contents ( tli bigint, start_lsn pg_lsn, end_lsn pg_lsn )
+        setof record
+        ( relfilenode oid,
+        reltablespace oid,
+        reldatabase oid,
+        relforknumber smallint,
+        relblocknumber bigint,
+        is_limit_block boolean )
+       
+       
+        Returns one information about the contents of a single WAL summary file
+        identified by TLI and starting and ending LSNs. Each row with
+        is_limit_block false indicates that the block
+        identified by the remaining output columns was modified by at least
+        one WAL record within the range of records summarized by this file.
+        Each row with is_limit_block true indicates either
+        that (a) the relation fork was truncated to the length given by
+        relblocknumber within the relevant range of WAL
+        records or (b) that the relation fork was created or dropped within
+        the relevant range of WAL records; in such cases,
+        relblocknumber will be zero.
+       
+      
+     
+    
+   
+
+  
+