| PGA components [message #145944] |
Mon, 07 November 2005 17:16 |
troglodita2
Messages: 2
Registered: November 2005
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Junior Member |
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Books and manuals have different ways to explain PGA structure and it has confused me.
From Fundamentals I Course Manual 9i + Oracle 9i Database Concepts
Pga = private sql area (persistent + runtime) + session memory
Where:
Persistent area contains bind variables.
Session memory comprises session's variables (logon information, etc.)
Runtime area includes SQL Work Area that is used for complex queries with sorts, joins, etc.
Location of memory structures In Shared Server:
Session memory + persistent + runtime for SELECT are located in SGA
From Fundamentals II & Tuning Course Manual 9i & One-on-one book 8i
PGA = UGA (User session data + cursor state + sort area) + Stack Space
Where:
- User session data includes security and resource usage information
- Cursor state contains runtime memory values for the SQL statement,such as rows retrieved.
- Stack space contains local variables for the process
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(question 1) What are the relations between these concepts ?, is "private sql area" included in "session memory" ?, "sql Work area" is a synonym of "sort area" ?, what is the correspondence
between "runtime area" and "cursor state" ?.
(question 2) What are the difference between bind variables (located in persistent area) and local variables (stored in Stack area) ?
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Thanks in advance,
Troglo
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