Postgres OnLine Journal - 9.4

http extension for windows updated to include PostgreSQL18 64-bit

nospam@example.com (Leo Hsu and Regina Obe) — Thu, 16 Oct 2025 23:03:00 -0400

Updated October 16th, 2025 64-bit package for PostgreSQL 18 http extension v1.7.0 release.

For those folks on windows who want to do http gets and posts directly from your PostgreSQL server, we've made binaries for the http extension for PostgreSQL Windows.

These are designed to work with PostgreSQL EDB windows distributions.

If you have PostGIS already installed, many of these files you will also already have since things like the libcurl and PCRE are also packaged with PostGIS.

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VARIADIC Unnest

nospam@example.com (Leo Hsu and Regina Obe) — Wed, 23 Nov 2022 00:26:00 -0500

PostgreSQL keeps on adding new great stuff. It's hard to remember all the good stuff that has been added over the years. One of the neat ones from the past is the variadic Unnest function which I believe was introduced in PostgreSQL 9.4. It's rare that I ever had to use it, but today I was handed some data where this function was just literally what the doctor ordered. I can't do anything this sweet in other databases I have used.

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PostGIS 2.5.1 Bundle for Windows

nospam@example.com (Leo Hsu and Regina Obe) — Sun, 09 Dec 2018 19:18:00 -0500

PostGIS 2.5.1 was released on November 18th 2018 and I finished off packaging the PostGIS 2.5.1 windows builds and installers targeted for PostgreSQL EDB distribution this weekend and pushing them up to stackbuilder. This covers PostgreSQL 9.4-11 64-bit and PostgreSQL 95-10 (32bit).

Note that PostGIS 2.5 series will be the last of the PostGIS 2s. Goodbye PostGIS 2.* and start playing with the in-development version of PostGIS 3. Snapshot binaries for PostGIS 3.0 windows development are also available on the PostGIS windows download page. These should work for both BigSQL and EDB distributions.

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Unpivoting data using JSON functions

nospam@example.com (Leo Hsu and Regina Obe) — Thu, 14 Jun 2018 03:12:00 -0400

Most of our use-cases for the built-in json support in PostgreSQL is not to implement schemaless design storage, but instead to remold data. Remolding can take the form of restructuring data into json documents suitable for web maps, javascript charting web apps, or datagrids. It also has uses beyond just outputting data in json form. In addition the functions are useful for unraveling json data into a more meaningful relational form.

One of the common cases we use json support is what we call UNPIVOTING data. We demonstrated this in Postgres Vision 2018 presentation in slide 23. This trick won't work in other relational databases that support JSON because it also uses a long existing feature of PostgreSQL to be able to treat a row as a data field.

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PostgreSQL JSQuery extension Windows binaries

nospam@example.com (Leo Hsu and Regina Obe) — Fri, 12 May 2017 20:02:06 -0400

PostgreSQL JSQuery extension Windows binaries

The JSQuery extension is a PostgreSQL extension developed by Postgres Professional. You can get the source code and instructions for use at https://github.com/postgrespro/jsquery. JSQuery is a fairly easy compile install if you are on a Nix system. It provides more query functionality and additional index operator classes to support for JSONB than you get in built in PostgreSQL. It is supported for PostgreSQL 9.4 and above.

We've built windows binaries for PostgreSQL 64-bit 9.4, 9.5, 9.6, and 10beta1. The 9.4 64-bit will only install on the EDB PostgreSQL 9.4 64-bit distribution. The 9.5 and 9.6 are compatible with both PostgreSQL EDB and BigSQL distributions. The 10 has only been tested on BigSQL, but should work on EDB when it comes out. We should have 32-bit versions later and will link to those here.

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regexp_split_to_table and string_to_array unnest performance

nospam@example.com (Leo Hsu and Regina Obe) — Fri, 01 Jul 2016 23:13:00 -0400

Whenever you need to split a text into multiple records breaking by some delimeter, there are two common options that PostgreSQL provides. The first is regpexp_split_to_table and then next popular is using the unnest function in combination with string_to_array.

Here is an example using regexp_split_to_table:

SELECT a
FROM regexp_split_to_table('john,smith,jones', ',') AS a;

Which outputs:

   a
-------
 john
 smith
 jones
(3 rows)

You can achieve the same result by using the construct:

SELECT a
FROM unnest(string_to_array('john,smith,jones', ',')) AS a;

With short text you won't notice much perfomance difference. But what happens if we pass in a humungous text?

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PostGIS 2.2 Windows users hold off on installing latest PostgreSQL patch release

nospam@example.com (Leo Hsu and Regina Obe) — Sat, 02 Apr 2016 11:34:00 -0400

Someone reported recently on PostGIS mailing list, that they were unable to install PostGIS 2.2.1 bundle or PostGIS 2.2.2 binaries on a clean PostgreSQL 9.5.2 install. Someone also complained about PostgreSQL 9.3 (though not clear the version) if that is a separate issue or the same. I have tested on PostgreSQL 9.5.2 Windows 64-bit and confirmed the issue. The issue does not affect PostgreSQL 9.5.1 and older. I haven't confirmed its an issue with the 32-bit installs, but I suspect so too. This issue will affect OGR_FDW users and people who used our compiled WWW_FDW.

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Import Foreign Schema hack with OGR_FDW and reading LibreOffice calc workbooks

nospam@example.com (Leo Hsu and Regina Obe) — Thu, 07 Jan 2016 02:59:00 -0500

PostgreSQL 9.4 and below doesn't support importing whole set of tables from a FOREIGN server, but PostgreSQL 9.5 does with the upcoming Import Foreign Schema. To use will require FDW wrapper designers to be aware of this feature and use the plumbing in their wrappers. IMPORT FOREIGN SCHEMA for ogr_fdw come PostgreSQL 9.5 release is on the features ticket list.

UPDATE: If you are using PostgreSQL 9.5+, you can use the IMPORT FOREIGN SCHEMA feature which is available in ogr_fdw 1.0.1+. We demonstrate this in: ogr fdw IMPORT FOREIGN SCHEMA.

The ogr_fdw comes with this to die for commandline utility called ogr_fdw_info that does generate the table structures for you and will also list all the tables in the Foreign data source if you don't give it a specific table name. So with this utility I wrote a little hack involving using PostgreSQL COPY PROGRAM feature to call out to the ogr_fdw_info commandline tool to figure out the table names and some DO magic to create the tables.

Though ogr_fdw is designed to be a spatial foreign data wrapper, it's turning out to be a pretty nice non-spatial FDW as well especially for reading spreadsheets which we seem to get a lot of. This hack I am about to demonstrate I am demonstrating with LibreOffice/OpenOffice workbook, but works equally well with Excel workbooks and most any data source that OGR supports.

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PostgreSQL OGR FDW update and PostGIS 2.2 news

nospam@example.com (Leo Hsu and Regina Obe) — Mon, 29 Jun 2015 05:24:00 -0400

PostGIS 2.2 is planned to reach feature freeze June 30th 2015 so we can make the September PostgreSQL 9.5 curtain call with confidence. Great KNN enhancements for PostgreSQL 9.5 only users. I've been busy getting all my ducks lined up. A lot on tiger geocoder and address standardizer extension to be shipped with windows builds, story for later. One other feature we plan to ship with the windows PostGIS 2.2 builds is the ogr_fdw ogr_fdw Foreign data wrapper extension. I've been nagging Paul Ramsey a lot about issues with it, this in particular https://github.com/pramsey/pgsql-ogr-fdw/issues/25, and after some prodding, he finally put his nose in and fixed them and pinged Even Rouault for some help on a GDAL specific item.

Needless to say, I've been super happy with the progress and support I've gotten with ogr_fdw development and really enjoying my ogr_fdw use. The XLSX reading a file saved after the connection was open required a fix in GDAL 2.0 branch (which missed GDAL 2.0.0 release, so because of this, this new package contains a GDAL 2.0.1ish library. Hopeful GDAL 2.0.1 will be out before PostGIS 2.2.0 comes out so I can release without guilt with this fix.

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Adding properties to existing JSON object with PLV8

nospam@example.com (Leo Hsu and Regina Obe) — Mon, 04 May 2015 01:45:00 -0400

Lately I've been experimenting with building semi-schemaless apps. These are apps where much of the data may never be used for reporting aside from story telling and also that as time goes by some of these may be revisited and converted to more structured fields for easier roll-up and reporting. For the front-end UI, I'm using AngularJS which naturally spits out data as JSON and can autobind to JSON data of any complexity. My stored functions in PostgreSQL take JSON blobs as inputs spit it out into various tables and throws the whole thing in a jsonb field for later consumption (it's a bit redundant). Similarly they return JSON back. One of the things I wanted to be able to do was take this jsonb blob and tack on additional properties from well-structured fields or even a whole set of data like sub recordsets to feed back to my app in JSON. While there are lots of functions in PostgreSQL 9.3/9.4 that can easily build json objects from records, aggregate rows, etc. I couldn't find a function that allowed me to just add a property to an existing JSON object, so I went to my tried and true old-pal PL/V8 for some comfort. Here is a quickie function I created in PL/V8 that did what I needed. Hopefully it will be of use to others or others might have other ideas of doing this that I missed.

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LATERAL WITH ORDINALITY - numbering sets

nospam@example.com (Leo Hsu and Regina Obe) — Sun, 01 Mar 2015 18:35:00 -0500

One of the neat little features that arrived at PostgreSQL 9.4 is the WITH ORDINALITY ANSI-SQL construct. What this construct does is to tack an additional column called ordinality as an additional column when you use a set returning function in the FROM part of an SQL Statement.

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Querying MS Access and other ODBC data sources with OGR_FDW

nospam@example.com (Leo Hsu and Regina Obe) — Tue, 10 Feb 2015 01:30:00 -0500

If you have the OGR_FDW we discussed in OGR FDW Windows first taste built with ODBC support, then you can access most any ODBC datasource from PostgreSQL. This is especially useful for Windows users. Two of the data sources I've been experimenting with are SQL Server and MS Access. In this article, I'll demonstrate how to connect to MS Access with PostgreSQL running on a windows box. I think there is an Access driver for Unix/Linux most robust utilizes java. I won't go there.

Registry hack should no longer be needed for PostGIS 2.2 ogr_fdw bundle and up since these come packaged with newer GDAL libraries that have the fix.

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Using SSL https connections with www_fdw on windows

nospam@example.com (Leo Hsu and Regina Obe) — Sat, 24 Jan 2015 13:35:00 -0500

One of the foreign data wrappers I included in the PostgreSQL 9.3 Windows FDW bag and PostgreSQL 9.4 Windows FDW bag is the www_fdw extension used for querying web services. Someone asked that since I didn't build curl with SSL support, they are unable to use it with https connections. The main reason I didn't is that the EDB installs come with ssleay32.dll and libeay32.dll (even the 64-bit) which are dependencies of curl when built with SSL support. I wanted to minimize the issue of distributing dlls that are packaged with Windows PostgreSQL installers already.

Though this article is specific to using www_fdw on Windows systems, many of the issues are equally applicable to other platforms, so may be worth a read if you are running into similar issues with using specialty SSL certificates on Linux/Unix/Mac.

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PLV8 binaries for PostgreSQL 9.4 windows both 32-bit and 64-bit

nospam@example.com (Leo Hsu and Regina Obe) — Tue, 06 Jan 2015 00:53:00 -0500

I'm still in the middle of building packages for our clients for the packages that aren't normally distributed for windows to make upgrading to PostgreSQL 9.4 smooth. One of those is PL/V8 which we use for some custom functions. I had mentioned how I build PL/V8 for PostgreSQL windows, and the instructions are a bit out of date., but I put more up to date instructions on my gist page. I tend to use gist a lot as a public scrap book with hopes someone else can learn from my toils and save them some trouble. At some point I should probably get more organized with my scrapbooks.

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Foreign Data Wrappers for PostgreSQL 9.4 Windows

nospam@example.com (Leo Hsu and Regina Obe) — Sun, 28 Dec 2014 06:02:00 -0500

As stated in last article, I've packaged FDW binaries for PostgreSQL 9.4 windows 32-bit and 64-bit and added in the ogr_fdw one. These we've tested with the standard EDB VS built PostgreSQL windows installs and work fine with those.

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