In Oracle 19c, monitoring and managing tablespaces are fundamental tasks for DBAs to ensure the efficiency, stability, and performance of databases. Proper management of tablespaces directly impacts how data is stored, retrieved, and maintained within the system. From viewing tablespace usage to checking tablespace allocation, DBAs need to maintain an organized and well-structured approach to avoid potential bottlenecks and ensure optimal resource utilization.
This comprehensive guide covers everything you need to know about tablespace monitoring in Oracle 19c. We will delve into the processes of tracking tablespace usage, understanding data growth, and proactively managing space allocation. Additionally, we’ll cover some critical SQL queries to help you check tablespace information and apply best practices for database performance and scalability.
The Importance of Viewing Tablespace Information
Efficient viewing tablespace information allows DBAs to understand the current state of their database’s storage, which is crucial for capacity planning and performance optimization. Tablespaces in Oracle serve as logical storage units that contain various database objects, such as tables and indexes. These objects are physically stored in datafiles that reside on disk, and understanding how they are used helps DBAs manage space effectively.
Oracle databases rely on tablespace monitoring to maintain smooth operations. When tracking tablespace information, DBAs should regularly review the space usage, extend datafiles when necessary, and ensure that adequate storage is available for future growth. By checking tablespace information, DBAs can prevent potential performance degradation caused by space exhaustion or inefficient data placement.
Key Queries for Viewing Tablespace Information
Oracle provides several queries that help DBAs view tablespace information across different database versions. Below are some essential queries tailored for Oracle 19c, 11g, 10g, and ASM environments to ensure comprehensive tablespace monitoring and tracking tablespace usage effectively.
Viewing Tablespace in Oracle 11g and Above
set line 200
set pages 300
column tablespace format A26
column KPERC format 99
Column Tipo format A4
SELECT * FROM (
select t.tablespace_name "Tablespace",
substr(t.contents, 1, 1) "Tipo",
trunc((d.tbs_size-nvl(s.free_space, 0))/1024/1024) "Used(MB)",
trunc(d.tbs_size/1024/1024) "ActualSize(MB)",
trunc(nvl(s.free_space, 0)/1024/1024) "FreeSpace(MB)",
trunc(d.tbs_maxsize/1024/1024) "MaxSize(MB)",
decode(d.tbs_maxsize, 0, 0, trunc((d.tbs_size-nvl(s.free_space, 0))*100/d.tbs_maxsize)) "PERC(%)"
from
(select SUM(bytes) tbs_size,
SUM(decode(sign(maxbytes - bytes), -1, bytes, maxbytes)) tbs_maxsize,
tablespace_name tablespace
from (select nvl(bytes, 0) bytes, nvl(maxbytes, 0) maxbytes, tablespace_name
from dba_data_files)
group by tablespace_name
union
select SUM(bytes) tbs_size,
SUM(decode(sign(maxbytes - bytes), -1, bytes, maxbytes)) tbs_maxsize,
tablespace_name tablespace
from (select nvl(bytes, 0) bytes, nvl(maxbytes, 0) maxbytes, tablespace_name
from dba_temp_files)
group by tablespace_name) d,
(SELECT free_space, tablespace_name tablespace
FROM dba_temp_free_space
UNION
SELECT SUM (bytes) free_space, tablespace_name tablespace
FROM dba_free_space
GROUP BY tablespace_name) s,
dba_tablespaces t
where t.tablespace_name = d.tablespace(+)
and t.tablespace_name = s.tablespace(+)
order by "PERC(%)"
);
This query provides a detailed overview of tablespace monitoring, including space usage, free space, and overall storage allocation. It is essential for DBAs who need to regularly check tablespace data to ensure that storage requirements are being met.
Viewing Tablespace in Oracle 10g
set line 2000
column tablespace format A17
column KPERC format 99
set page 50
SELECT * FROM (
select t.tablespace_name "Tablespace",
substr(t.contents, 1, 1) "Tipo",
trunc((d.tbs_size-nvl(s.free_space, 0))/1024/1024) "Used(MB)",
trunc(d.tbs_size/1024/1024) "ActualSize(MB)",
trunc(nvl(s.free_space, 0)/1024/1024) "FreeSpace(MB)",
trunc(d.tbs_maxsize/1024/1024) "MaxSize(MB)",
decode(d.tbs_maxsize, 0, 0, trunc((d.tbs_size-nvl(s.free_space, 0))*100/d.tbs_maxsize)) "PERC(%)"
from
(select SUM(bytes) tbs_size,
SUM(decode(sign(maxbytes - bytes), -1, bytes, maxbytes)) tbs_maxsize,
tablespace_name tablespace
from (select nvl(bytes, 0) bytes, nvl(maxbytes, 0) maxbytes, tablespace_name
from dba_data_files)
group by tablespace_name
union
select SUM(bytes) tbs_size,
SUM(decode(sign(maxbytes - bytes), -1, bytes, maxbytes)) tbs_maxsize,
tablespace_name tablespace
from (select nvl(bytes, 0) bytes, nvl(maxbytes, 0) maxbytes, tablespace_name
from dba_temp_files)
group by tablespace_name) d,
(SELECT SUM(bytes) free_space, tablespace_name tablespace
FROM dba_free_space
GROUP BY tablespace_name) s,
dba_tablespaces t
where t.tablespace_name = d.tablespace(+)
and t.tablespace_name = s.tablespace(+)
order by "PERC(%)"
);
This query is tailored for Oracle 10g environments and provides insight into tracking tablespace usage, ensuring that your storage infrastructure can handle the demands of the database.
Monitoring ASM Diskgroup Space
SET LINESIZE 145
SET PAGESIZE 9999
SET VERIFY off
COLUMN group_name FORMAT a20 HEAD 'Disk Group|Name'
COLUMN sector_size FORMAT 99,999 HEAD 'Sector|Size'
COLUMN block_size FORMAT 99,999 HEAD 'Block|Size'
COLUMN allocation_unit_size FORMAT 999,999,999 HEAD 'Allocation|Unit Size'
COLUMN state FORMAT a11 HEAD 'State'
COLUMN type FORMAT a6 HEAD 'Type'
COLUMN total_mb FORMAT 999,999,999 HEAD 'Total Size (MB)'
COLUMN free_mb FORMAT 999,999,999 HEAD 'Free Size (MB)'
COLUMN used_mb FORMAT 999,999,999 HEAD 'Used Size (MB)'
COLUMN pct_used FORMAT 999.99 HEAD 'Pct. Used'
break on report on disk_group_name skip 1
compute sum label "Grand Total: " of total_mb used_mb on report
SELECT name group_name,
sector_size sector_size,
block_size block_size,
allocation_unit_size allocation_unit_size,
state state,
type type,
total_mb total_mb,
(total_mb - free_mb) used_mb,
free_mb free_mb,
ROUND((1- (free_mb / total_mb))*100, 2) pct_used
FROM
v$asm_diskgroup
ORDER BY
name
/
The above query is designed for DBAs working in Oracle ASM environments, providing an in-depth view of disk group space usage, viewing tablespace information effectively, and ensuring adequate storage is available for your Oracle instances.
Best Practices for Viewing and Managing Tablespace Information
To effectively view tablespace information and manage Oracle tablespaces, DBAs should adhere to the following best practices:
- Regularly monitor tablespace usage: By consistently tracking tablespace usage, DBAs can avoid potential issues related to space exhaustion and ensure that storage is optimized for performance.
- Automate where possible: Leveraging tools like ASM and OMF reduces manual tasks, decreases the likelihood of errors, and ensures consistency in storage management across the environment.
- Perform regular tablespace analysis: Regular analysis helps you stay ahead of storage needs, identifying trends in data growth and checking tablespace usage proactively to avoid space-related issues.
- Use multiple tablespaces for different workloads: By separating data types into different tablespaces, you can reduce I/O contention, improve performance, and optimize your backup strategies.
Conclusion
Managing tablespaces effectively is critical for ensuring the performance and scalability of your Oracle 19c environment. By regularly viewing tablespace information, DBAs can ensure that their databases are optimized for growth, performance, and availability. Through tracking tablespace usage and applying best practices, such as tablespace monitoring and automation, DBAs can stay proactive and keep their databases running smoothly.
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