Hello,
Greg Stark wrote:
Tom Lane <[EMAIL PROTECTED]> writes:
The paragraph continues:
"If the SELECT command included the clause WHERE phone NOT NULL, PostgreSQL could use the index to satisfy the ORDER BY clause.
An index that covers optional (NOT NULL) columns will not be used to speed table joins either."
My goodness, it seems to be a veritable fount of misinformation :-(
I wonder if they just tried explain on a bunch of queries and noticed that postgres wasn't using an index for SELECT * FROM foo ORDER BY bar and came up with explanations for the patterns they saw?
This paragraph was in the chapter about PostgreSQL indexing and the paragraph itself was entitled "Indexes and Null values".
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Regards/Gruß,
Tarlika Elisabeth Schmitz
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