The following table shows the relationships among environment variables and connection types for connecting with the HiRDB server.

Table 6-38 Relationships between environment variables and connection types

Environment variable	HiRDB/Single Server		HiRDB/Parallel Server
			Single front-end server		Multiple front-end servers
	Normal	High- speed	Normal	High- speed	Normal	Connection with specific front-end server
						FES-host direct	High- speed
PDHOST	S	S	S	S	S	S	S
PDFESHOST	--	--	--	S#	--	S	S#
PDNAMEPORT	S	S	S	S	S	S	S
PDSERVICEPORT	--	S	--	S#	--	--	S#
PDSERVICEGRP	--	S	--	S#	--	S	S#
PDFESGRP	--	--	--	S#	--	--	S#
PDSRVTYPE	--		--		--	--

S: Must be specified.

: Must be specified if the HiRDB server is the Linux or Windows edition.

--: Does not have to be specified.

Notes

1. The connection format in which all required environment variables are specified is selected in the priority order of high-speed connection, FES-host direct connection, and normal connection. Unnecessary environment variables are not used.
2. The following relationships apply to the connection time to the HiRDB server and the number of TCP ports used during connection:
   Normal connection time > FES-host direct connection time > high-speed connection time
   

A high-speed connection is recommended if you want to shorten the connection time. A normal connection is recommended in order to use the connected front-end server efficiently.

If you want to reduce the number of TCP ports required when a normal connection is used, specify 1 in PDTCPCONOPT in the client environment definition. For details about PDTCPCONOPT, see 6.6.4 Environment definition information.

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There are two ways to specify high-speed connection:

• Specify PDFESHOST, PDSERVICEGRP, and PDSERVICEPORT
• Specify PDFESGRP

If you specify only one host name in PDFESHOST or PDFESGRP, the two methods above are treated as being the same. If you specify multiple host names, the specification method depends on the conditions shown in the following table:

No.	Condition for specifying multiple host names		Environment variables to be specified
	System switchover facility	Number of FESs
1	The system switchover facility is used on the unit where the FES is located and the IP address of the primary system used for connection from the client is different from the IP address of the secondary system.	1	PDFESHOST, PDSERVICEGRP, and PDSERVICEPORT
2		Multiple	PDFESHOST, PDSERVICEGRP, and PDSERVICEPORT
3	Other than the above	Multiple	PDFESGRP

In No. 2, there are multiple FESs (multiple front-end servers), but you must specify PDFESHOST, PDSERVICEGRP, and PDSERVICEPORT and use only one FES as the connection target. If multiple FESs are specified in PDFESGRP and an error (KFPA11932-E) occurs in the running system due to too many connected users, the following problems might occur:

• An unnecessary attempt is made to connect to the standby system.
• If a connection error occurs in all FES groups and the FES group for which the last connection attempt was made is a standby system, information about errors only in the standby system is returned to the UAP, making it impossible to detect an error that might be caused by too many connected users in the running system.