New query for 'Manage Database' option in SQL Developer

Question

Dear all,
I want to suggest a changed query for the 'Manage Database' option in SQL Developer (right-click on the connection), see the query below.
This query has the following changes;
- extra column with the Maximum disk space based on the datafiles (considering autoextend of datafiles); MAX_DATAFILES
- the PERCENT_USED and PCT_USED are based on the MAX_DATAFILES, as this is really important (and not the difference between ALLOCATED and USED)
- the results are shown in GB, as that is in my opinion more relevant in this time of data explosion
- rename of the column FREE to UNUSED_ALLOCATED, as this column identifies how much of the Allocated space is not used
I hope the query can replace the current one, to improve SQL Developer even more.
Thanks for the nice tool SQL Developer!
Kind regards,
Siebe
-- Manage Database - Changed Oracle SQL Developer query with regard to Usage of Tablespaces in GB (considering autoextend of datafiles)
SELECT "TABLESPACE_NAME", "PERCENT_USED", "PCT_USED", "MAX_DATAFILES", "ALLOCATED", "USED", "UNUSED_ALLOCATED", "DATAFILES" FROM(
select * from (
SELECT a.tablespace_name,
--'SQLDEV:GAUGE:0:100:0:0:'||nvl(ROUND(((c.bytes-nvl(b.bytes,0))/c.bytes)*100,2),0) percent_used,
--ROUND(((c.bytes-nvl(b.bytes,0))/c.bytes)*100,2) PCT_USED,
'SQLDEV:GAUGE:0:100:0:0:'||nvl(ROUND(((c.bytes-nvl(b.bytes,0))/c.maxbytes)*100,2),0) percent_used,
ROUND(((c.bytes-nvl(b.bytes,0))/c.maxbytes)*100,2) PCT_USED,
round(c.bytes/1024/1024/1024,2) allocated,
round(c.bytes/1024/1024/1024-nvl(b.bytes,0)/1024/1024/1024,2) used,
round(c.maxbytes/1024/1024/1024,2) max_datafiles,
round(nvl(b.bytes,0)/1024/1024/1024,2) unused_allocated,
c.datafiles
FROM dba_tablespaces a,
( SELECT tablespace_name, SUM(bytes) bytes FROM dba_free_space GROUP BY tablespace_name ) b,
( select count(1) datafiles, SUM(bytes) bytes, SUM(DECODE(autoextensible, 'YES', maxbytes, bytes)) maxbytes, tablespace_name from dba_data_files GROUP BY tablespace_name ) c
--( select count(1) datafiles, SUM(bytes) bytes, SUM(c.maxbytes) maxbytes, tablespace_name from dba_data_files GROUP BY tablespace_name ) c
WHERE b.tablespace_name (+) = a.tablespace_name
AND c.tablespace_name (+) = a.tablespace_name
ORDER BY nvl(((c.bytes-nvl(b.bytes,0))/c.maxbytes),0) DESC
) --sub1 order by 1 asc
)

Answer 1

Very little technical information provided about the error.
"+IO error.+" - this likely refers to the client attempting to use a socket handle and the call to the handle failing.
+"The network adapter could not establish the connection.+" - this likely means that the IP address to connect to, could not be reached, or that the connection was not accepted on that port on the remote IP address. (typically hostname resolution errors would give a different error)
The easiest way to test connectivity is using the ping command to bounce an ICMP echo off the remote IP.
If that works, test access to remote port on that remote IP using the telnet command - this will check whether there is a service accepting connections on that port, and whether access to that port is allowed in case of firewalls en-route.