193.121.160.69: Created page with "Enable flash cache: alter system set db_flash_cache_file='/flash/cache.dbf' scope=spfile; alter system set db_flash_cache_size=10G scope=spfile; ..."

2016-04-05T10:10:31Z

Created page with "Enable flash cache: <source lang="sql"> alter system set db_flash_cache_file='/flash/cache.dbf' scope=spfile; alter system set db_flash_cache_size=10G scope=spfile; </source>..."

New page

Enable flash cache:
<source lang="sql">
alter system set db_flash_cache_file='/flash/cache.dbf' scope=spfile;
alter system set db_flash_cache_size=10G scope=spfile;
</source>

Prevent flash cache from turning off due to small interruption:
<source lang="sql">
alter system set _db_flash_cache_max_latency=200;
alter system set _db_flash_cache_max_slow_io=10000;
</source>

In case flash cache is turned off due to a latency error, it can be re-enabled by setting the size to 0 (disabling flash cache), then setting the size back to the old setting. Online resizing of flash cache is not supported so only values 0 and the old value are valid settings.

Show contents of Flash cache:
<source lang="sql">
SELECT /*+ use_hash(o bh) */
owner
, object_name
, object_type
, count(1) * &block_size / 1048576 / 1024 "Size (GB)"
FROM dba_objects o
, v$bh bh
WHERE o.data_object_id = bh.objd
AND bh.status IN ('flashcur')
GROUP BY owner, object_name, object_type
ORDER BY count(1) desc;
</source>

Size of flash cache:
<source lang="sql">
SELECT count(1) * &block_size / 1048576 / 1024 "Size (GB)"
FROM v$bh bh
WHERE bh.status IN ('flashcur');
</source>

Flash Cache - Revision history

193.121.160.69: Created page with "Enable flash cache: alter system set db_flash_cache_file='/flash/cache.dbf' scope=spfile; alter system set db_flash_cache_size=10G scope=spfile; ..."