\ud83d\udccc Note: Dirty buffers are never<\/strong> written to flash cache \u2014 only clean buffers go there.<\/p>\n\n\n\n Smart configuration of the buffer cache can dramatically reduce physical disk reads. Use the Keep Pool for frequently accessed tables, the Recycle Pool for transient data, and consider Flash Cache if you’re working with large datasets and flash storage.<\/p>\n","protected":false},"excerpt":{"rendered":" \ud83e\udde0 Introduction When your Oracle database needs to read or write data, it doesn\u2019t always hit the disk directly. Instead, it uses a special memory area called the Database Buffer Cache to speed things up. Let\u2019s break down what this means. \ud83e\udde9 What is the Database Buffer Cache? The Database Buffer Cache is part of […]<\/p>\n","protected":false},"template":"","meta":{"googlesitekit_rrm_CAowu461DA:productID":""},"categories":[960,952],"class_list":["post-3695","cposts","type-cposts","status-publish","hentry","category-getting-started-with-oracle-dba","category-notes"],"_links":{"self":[{"href":"https:\/\/w3buddy.com\/blog\/wp-json\/wp\/v2\/cposts\/3695","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/w3buddy.com\/blog\/wp-json\/wp\/v2\/cposts"}],"about":[{"href":"https:\/\/w3buddy.com\/blog\/wp-json\/wp\/v2\/types\/cposts"}],"wp:attachment":[{"href":"https:\/\/w3buddy.com\/blog\/wp-json\/wp\/v2\/media?parent=3695"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/w3buddy.com\/blog\/wp-json\/wp\/v2\/categories?post=3695"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
When your Oracle database needs to read or write data, it doesn\u2019t always hit the disk directly. Instead, it uses a special memory area called the Database Buffer Cache<\/strong> to speed things up. Let\u2019s break down what this means.<\/p>\n\n\n\n\ud83e\udde9 What is the Database Buffer Cache?<\/h2>\n\n\n\n
The Database Buffer Cache is part of the System Global Area (SGA)<\/strong> \u2014 a shared memory pool in the Oracle instance. It stores copies of data blocks recently read from data files, allowing fast access by multiple users connected concurrently.<\/p>\n\n\n\n\ud83c\udfaf Why Use the Buffer Cache?<\/h2>\n\n\n\n
\n
\u2699\ufe0f How It Works<\/h2>\n\n\n\n
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\ud83e\udde0 Components of the Buffer Cache<\/h2>\n\n\n\n
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\u27a4 Main area where data blocks are cached (default block size 8 KB)
\u27a4 It\u2019s the only pool unless other pools are configured<\/li>\n\n\n\n
\u27a4 For frequently accessed blocks you want to “keep” in memory
\u27a4 Objects must be explicitly assigned to this pool<\/li>\n\n\n\n
\u27a4 For blocks that are accessed rarely
\u27a4 Helps prevent such blocks from using space in the default pool<\/li>\n\n\n\n
\u27a4 For tablespaces using non-standard block sizes (2 KB, 4 KB, 16 KB, 32 KB)
\u27a4 Each block size has its own buffer pool<\/li>\n<\/ul>\n\n\n\n\ud83e\udde9 Other Important Concepts<\/h2>\n\n\n\n
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\u27a4 Tracks buffer usage
\u27a4 “Hot” buffers (recently used) stay in memory; “cold” ones get aged out<\/li>\n\n\n\n
\u27a4 List of dirty buffers to be written to disk, ordered by redo block address<\/li>\n\n\n\n
\u27a4 Extends the buffer cache using flash storage
\u27a4 Only clean buffers are written here
\u27a4 Faster than disk but slower than memory
\u27a4 Separate LRU chains for DEFAULT and KEEP<\/li>\n<\/ul>\n\n\n\n\ud83d\udee0\ufe0f DBA Tip of the Day<\/h2>\n\n\n\n