SAP Note 15798 - INF2558x SQL Error: Network Receive Failed

Symptom:

When the database is running 2558x SQL errors occur sporadically,
e.g.:
INF25580: -25580 System error occurred in network function.
INF25582: -25582 Network connection is broken.
INF25583: -25583 Unknown network error.
INF25584: -25584 Network driver cannot access the server program
INF25586: -25586 Network send failed.
INF25587: -25587 Network receive failed.
INF25588: -25588 The appl process cannot connect to OnLine server

Possibly only the four-digit SQL error is contained in the SYSLOG
INF2558: -2558 together with the corresponding error message.

Cause and prerequisites

Communication between the front-end process (application) and the back-end process (database server) has been interrupted (for a short time), e.g. as a result of a network instability.

Solution
Normally, it is sufficient to restart the interrupted action.
If error 25588 occurs (the appl process cannot connect to OnLine server), you should restart the R/3 System and the database (startsap, stopsap).
Possibly the value for 'number of users' of the onconfig parameter NETTYPE was defined too small. In that case it must be increased.

Example:
old: NETTYPE ipcshm,1,30,CPU # Override sqlhosts nettype parameter
new: NETTYPE ipcshm,1,50,CPU # Override sqlhosts nettype parameter