Doc: add glossary term for "auxiliary process"

Add entries for existing processes not documented, too, and adjust
existing definitions for consistency.

Per question from Bharath Rupireddy.

Author: Justin Pryzby 
Author: Alvaro Herrera 
Discussion: https://postgr.es/m/CALj2ACVpYCT0M+k8zqrAa4ZQZV+ce5s6G=yajwoS1m=h-jj8NQ@mail.gmail.com

diff --git a/doc/src/sgml/glossary.sgml b/doc/src/sgml/glossary.sgml
index 63ff4bbdf06038e3759cea2805de82f44291d1a1..0c88988fa66bf995d7d8590bd78a04c73d228362 100644 (file)
--- a/doc/src/sgml/glossary.sgml
+++ b/doc/src/sgml/glossary.sgml
@@ -48,7 +48,7 @@
    Analyze (operation)
    
     
-     The process of collecting statistics from data in
+     The act of collecting statistics from data in
      tables
      and other relations
      to help the query planner
@@ -113,8 +113,12 @@
     
      A set of background processes that routinely perform
      vacuum
-     and analyze
-     operations.
+     and analyze operations.
+     The auxiliary process
+     that coordinates the work and is always present (unless autovacuum
+     is disabled) is known as the autovacuum launcher,
+     and the processes that carry out the tasks are known as the
+     autovacuum workers.
     
     
      For more information, see
@@ -123,6 +127,34 @@
    
   
 
+  
+   Auxiliary process
+   
+    
+     A process within an instance
+     that is in charge of some specific background task for the instance.
+     The auxiliary processes consist of 
+     
+     the autovacuum launcher
+     (but not the autovacuum workers),
+     the background writer,
+     the checkpointer,
+     the logger,
+     the startup process,
+     the statistics collector,
+     the WAL archiver,
+     the WAL receiver
+     (but not the WAL senders),
+     and the WAL writer.
+    
+   
+  
+
   
    Backend (process)
    
@@ -163,7 +195,8 @@
    Background writer (process)
    
     
-     A process that writes dirty
+     An auxiliary process
+     that writes dirty
      data pages from
      shared memory to
      the file system.  It wakes up periodically, but works only for a short
@@ -285,7 +318,9 @@
    Checkpointer (process)
    
     
-     A specialized process responsible for executing checkpoints.
+     An auxiliary process
+     that is responsible for executing
+     checkpoints.
     
    
   
@@ -778,8 +813,9 @@
    Instance
    
     
-     A group of backend and auxiliary processes that communicate using
-     a common shared memory area.  One
+     A group of backend and
+     auxiliary processes
+     that communicate using a common shared memory area.  One
      postmaster process
      manages the instance; one instance manages exactly one
      database cluster
@@ -881,8 +917,8 @@
    Logger (process)
    
     
-     If activated, the process
-     writes information about database events into the current
+     An auxiliary process
+     which, if enabled, writes information about database events into the current
      log file.
      When reaching certain time- or
      volume-dependent criteria, a new log file is created.
@@ -1040,8 +1076,9 @@
    
     
       The very first process of an instance.
-      It starts and manages the other auxiliary processes and creates
-      backend processes
+      It starts and manages the
+      auxiliary processes
+      and creates backend processes
       on demand.
     
     
@@ -1452,6 +1489,22 @@
    
   
 
+  
+   Startup process
+   
+    
+     An auxiliary process
+     that replays WAL during crash recovery and in a
+     physical replica.
+    
+    
+     (The name is historical: the startup process was named before
+     replication was implemented; the name refers to its task as it
+     relates to the server startup following a crash.)
+    
+   
+  
+
   
    SQL object
     
@@ -1514,8 +1567,10 @@
    Stats collector (process)
    
     
-     This process collects statistical information about the
-     instance's activities.
+     An auxiliary process
+     which, if enabled, receives statistical information
+     about the instance's
+     activities.
     
     
       For more information, see
@@ -1856,7 +1911,9 @@
    WAL archiver (process)
    
     
-     A process that saves copies of WAL files
+     An auxiliary process
+     which, if enabled, saves copies of
+     WAL files
      for the purpose of creating backups or keeping
      replicas current.
     
@@ -1914,11 +1971,44 @@
    
   
 
+  
+   WAL receiver
+   
+    
+     An auxiliary process
+     that runs on a replica
+     to receive WAL from the
+     primary server
+     for replay by the
+     startup process.
+    
+
+    
+     For more information, see
+     .
+    
+   
+  
+
   
    WAL segment
    
   
 
+  
+   WAL sender (process)
+   
+    
+     A special backend process
+     that streams WAL over a network.  The receiving end can be a
+     WAL receiver
+     in a replica,
+     , or any other client program
+     that speaks the replication protocol.
+    
+   
+  
+
   
    WAL writer (process)
    

diff --git a/src/include/miscadmin.h b/src/include/miscadmin.h
index 2e2e9a364a763ac04aec1cfe9372b0fedb0f569d..90a301606575b9279ba0c4eedd1cb035ac042867 100644 (file)
--- a/src/include/miscadmin.h
+++ b/src/include/miscadmin.h
@@ -422,6 +422,8 @@ extern ProcessingMode Mode;
  * Auxiliary-process type identifiers.  These used to be in bootstrap.h
  * but it seems saner to have them here, with the ProcessingMode stuff.
  * The MyAuxProcType global is defined and set in auxprocess.c.
+ *
+ * Make sure to list in the glossary any items you add here.
  */
 
 typedef enum