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authorAlvaro Herrera2013-07-02 16:21:16 +0000
committerAlvaro Herrera2013-07-02 17:14:02 +0000
commit8455b70fee2ddaabb5f76ed3aef11c97cbd10507 (patch)
tree9b426d62e902be747c88d85536c2124fb8e8b8b1
parent50e66d37aceee0f38c44f41834f39cfdda34c796 (diff)
Mention extra_float_digits in floating point docs
Make it easier for readers of the FP docs to find out about possibly truncated values. Per complaint from Tom Duffey in message [email protected] Author: Albe Laurenz Reviewed by: Abhijit Menon-Sen
-rw-r--r--doc/src/sgml/config.sgml1
-rw-r--r--doc/src/sgml/datatype.sgml11
2 files changed, 12 insertions, 0 deletions
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 7e67f9c2508..ca368412094 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -5024,6 +5024,7 @@ SET XML OPTION { DOCUMENT | CONTENT };
partially-significant digits; this is especially useful for dumping
float data that needs to be restored exactly. Or it can be set
negative to suppress unwanted digits.
+ See also <xref linkend="datatype-float">.
</para>
</listitem>
</varlistentry>
diff --git a/doc/src/sgml/datatype.sgml b/doc/src/sgml/datatype.sgml
index b7c51a4dee3..10ec158098d 100644
--- a/doc/src/sgml/datatype.sgml
+++ b/doc/src/sgml/datatype.sgml
@@ -672,6 +672,17 @@ NUMERIC
from zero will cause an underflow error.
</para>
+ <note>
+ <para>
+ The <xref linkend="guc-extra-float-digits"> setting controls the
+ number of extra significant digits included when a floating point
+ value is converted to text for output. With the default value of
+ <literal>0</literal>, the output is the same on every platform
+ supported by PostgreSQL. Increasing it will produce output that
+ more accurately represents the stored value, but may be unportable.
+ </para>
+ </note>
+
<indexterm>
<primary>not a number</primary>
<secondary>double precision</secondary>