From f52e6051f226ed77539962b8c4c440f7616feafd Mon Sep 17 00:00:00 2001
From: Tatsuo Ishii <ishii@postgresql.org>
Date: Sun, 1 Apr 2018 06:39:39 +0900
Subject: [PATCH] Update config README file.

---
 src/config/README | 44 +++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 43 insertions(+), 1 deletion(-)

diff --git a/src/config/README b/src/config/README
index b92b3f6fd..a7b23af8d 100644
--- a/src/config/README
+++ b/src/config/README
@@ -1,10 +1,12 @@
 How to add new config parameter
+===============================
 
 This document explains how to add a new configuration parameter. In We
 use new enum type configuration parameter
 "disable_load_balance_on_write" as an example.
 
 Step1: add enum definition
+==========================
 
 Add an enum type to src/include/pool_config.h.
 
@@ -17,6 +19,7 @@ typedef enum DLBOW_OPTION
 } DLBOW_OPTION;
 
 Step2: Add the new entry to POOL_CONFIG struct
+==============================================
 
 There's a struct called "POOL_CONFIG" holding all config
 variables. Add the new configparameter name along with the enum
@@ -35,6 +38,7 @@ defined above to src/include/pool_config.h.
 							 */
 
 Step3: Add config_emum_entery array to src/config/pool_config.c.
+================================================================
 
 static const struct config_enum_entry disable_load_balance_on_write_options[] = {
 	{"off", DLBOW_OFF, false},
@@ -44,7 +48,7 @@ static const struct config_enum_entry disable_load_balance_on_write_options[] =
 	{NULL, 0, false}
 };
 
-config_enum_entry is defined in src/include/pool_config.h:
+config_enum_entry is defined in src/include/pool_config_variable.h:
 
 /*
  * The possible values of an enum variable are specified by an array of
@@ -58,7 +62,42 @@ struct config_enum_entry
 	bool		hidden;
 };
 
+Other than enum config type, we have: config_bool, config_int,
+config_int_array, config_double, config_double_array, config_long,
+config_string, config_string_array, and config_list. See
+src/include/pool_config_variable.h for more details.
+
+Note that each config_* struct they have common data as struct
+config_generic.  config_generic is defined as follows in
+src/include/pool_config_variable.h:
+
+struct config_generic
+{
+	/* constant fields, must be set correctly in initial value: */
+	const char		*name;		/* name of variable - MUST BE FIRST */
+	ConfigContext	context;		/* context required to set the variable */
+	config_group	group;			/* to help organize variables by function */
+	const char		*description;	/* short desc. of this variable's purpose */
+	config_type		vartype;	/* type of variable (set only at startup) */
+	bool			dynamic_array_var;	/* true if the variable name contains index postfix */
+	int				flags;		/* flags */
+	int				max_elements;	/* number of maximum elements, only valid for array type configs */
+	int				status;		/* status bits, see below */
+	int				sourceline;	/* line in source file */
+
+
+	GucSource		*sources;	/* source of the current actual value, For array type config elements
+						 * it contains the corosponding source of each individual element */
+	GucSource		*reset_sources;	/* source of the reset value, For array type config elements
+						 * it contains the corosponding source of each individual element */
+	ConfigContext	*scontexts;		/* context that set the current value, For array type config elements
+						 * it contains the corosponding context of each individual element */
+
+};
+
+
 Step4: add an entry to static struct config_enum ConfigureNamesEnum[].
+=====================================================================
 
 	{
 		{"disable_load_balance_on_write", CFGCXT_RELOAD, LOAD_BALANCE_CONFIG,
@@ -108,11 +147,13 @@ struct config_generic
 
 
 Step5: add the new config parameter to example config files.
+============================================================
 
 You need to the new config sample to config example files under
 src/sample/pgpool.conf.sample*
 
 Step6: add the new config parameter to the report program.
+==========================================================
 
  src/utils/pool_process_reporting.c
 
@@ -122,3 +163,4 @@ Step6: add the new config parameter to the report program.
 	i++;
 
 Step7: remeber to add documents and tests!
+==========================================
-- 
2.39.5