DBLINK()

DBLINK() is a Vertica User Defined Transform Function coded in C++ to run SQL against other databases. The original repository is vertica / dblink.

For 'Usage' information, please refer to the README file in the original repository.

As of dblink 0.3.2, it has a limitation that DBLINK() is allowed to call only once in one query. The following error occurs if it is called multiple times.

=> SELECT l.id, l.description, tab_a.value value_a, tab_b.value value_b
-> FROM tab_local l
-> LEFT JOIN (SELECT DBLINK(USING PARAMETERS cid='orcl', query='SELECT * FROM tab1') OVER()) tab_a
->   ON tab_a.id = l.id
-> LEFT JOIN (SELECT DBLINK(USING PARAMETERS cid='orcl', query='SELECT * FROM tab1') OVER()) tab_b
->   ON tab_b.id = l.id;

ERROR 8092:  Failure in UDx RPC call InvokeProcessPartition() in User Defined Object [dblink]: UDx side process has exited abnormally

This repository provides DBLINK() without this limitation.

Installation

Set up your environment to meet C++ Requirements described on the following page. https://docs.vertica.com/latest/en/extending/developing-udxs/developing-with-sdk/setting-up-development-environment/

To compile the source codes in 24.1 or later version, run the following command:

$ make

In 23.4 or previous version, run the following command:

$ CXXFLAGS=-D_GLIBCXX_USE_CXX11_ABI=0 make

To install DBLINK function, run the following command:

$ make install

To uninstall DBLINK function, run the following command:

$ make uninstall

Notes

DBLINK function has been tested in Vertica 24.4.