Access Paths in Oracle

In this Blog we will discuss about various table access methods in oracle.

Access paths are the methods by which Oracle can get at our data
There are three broad categories of access paths
1.The infamous full scan
2.Index accesses
3.Directed access, by hash or ROWID

Table Full scans

Reads every block in a given segment that was used at some point or other (up to High Water Mark)
Can be most efficient access path for “small” tables
Are a very efficient method to read a lot of data, since it employs multi block read. i.e. can read multiple blocks in a single I/O
Can cause significant physical I/O, particularly on larger tables
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