Re: [HACKERS] PostgreSQL and SOAP, suggestions?

mlw Tue, 01 Apr 2003 16:36:18 -0800

That function looks great, but what happens if you need to return 1 million records? Wouldn't you exhaust all the memory in the server? Or can you stream it somehow?

I have an actual libpq program which performs a query against a server, and will stream out the XML, so the number of records has very little affect on efficiency. I think the table2xml function is great for 99% of all the queries, but for those huge resultsets, I think it may be problematic.

What do you think?

BTW, I routinely have queries that return millions of rows.

Peter Eisentraut wrote:

mlw writes:

Given a HTTP formatted query:
GET "http://localhost:8181/pgmuze?query=select+*+from+zsong+limit+2";

The output is entered below.


That looks a lot like the SQL/XML-style output plus a SOAP header.  Below
is the output that I get from the SQL/XML function that I wrote.  A simple
XSLT stylesheet should do the trick for you.

Btw., I also have an XSLT stylesheet that can make an HTML table out of
this output and I have a table function that can generate a virtual table
from this output.

=> select table2xml('select * from products');

<?xml version='1.0'?>
<table
   xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance'
   xsi:noNamespaceSchemaLocation='#'> <!-- XXX this needs to be fixed -->

<xsd:schema
   xmlns:xsd='http://www.w3.org/2001/XMLSchema'
   xmlns:sqlxml='http://www.iso-standards.org/mra/9075/2001/12/sqlxml'>

 <xsd:import
     namespace='http://www.iso-standards.org/mra/9075/2001/12/sqlxml'
     schemaLocation='http://www.iso-standards.org/mra/9075/2001/12/sqlxml.xsd' />

<xsd:simpleType name='peter.pg_catalog.text'>
 <xsd:restriction base='xsd:string'>
   <xsd:maxLength value='MLIT' /> <!-- XXX needs actual value -->
 </xsd:restriction>
</xsd:simpleType>

<xsd:simpleType name='INTEGER'>
 <xsd:restriction base='xsd:integer'>
   <xsd:maxInclusive value='2147483647'/>
   <xsd:minInclusive value='-2147483648'/>
 </xsd:restriction>
</xsd:simpleType>

<xsd:simpleType name='NUMERIC'>
 <xsd:restriction base='xsd:decimal'>
   <xsd:totalDigits value='PLIT'/> <!-- XXX needs actual values -->
   <xsd:fractionDigits value='SLIT'/>
 </xsd:restriction>
</xsd:simpleType>

<xsd:complexType name='RowType'>
 <xsd:sequence>
   <xsd:element name='name' type='peter.pg_catalog.text' nillable='true'></xsd:element>
   <xsd:element name='category' type='INTEGER' nillable='true'></xsd:element>
   <xsd:element name='price' type='NUMERIC' nillable='true'></xsd:element>
 </xsd:sequence>
</xsd:complexType>

<xsd:complexType name='TableType'>
 <xsd:sequence>
   <xsd:element name='row' type='RowType' minOccurs='0' maxOccurs='unbounded' />
 </xsd:sequence>
</xsd:complexType>

<xsd:element name='table' type='TableType' />

</xsd:schema>

 <row>
   <name>screwdriver</name>
   <category>3</category>
   <price>7.99</price>
 </row>

 <row>
   <name>drill</name>
   <category>9</category>
   <price>12.49</price>
 </row>

</table>

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Re: [HACKERS] PostgreSQL and SOAP, suggestions?

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