"Error: DPI-1047: Cannot locate a 64-bit Oracle Client library" when using `libDir`

[ericmorand]

I've been strugling with this bug for months: whenever I try to initialize the Oracle client, I get the following error:

Error: DPI-1047: Cannot locate a 64-bit Oracle Client library: "libnnz.so: cannot open shared object file: No such file or directory".

I'm initializing the client this way:

OracleDB.initOracleClient({
    libDir: '/home/ericmorand/Applications/instantclient_23_26'
});

It makes sense because, if I understand the documentation well, Linux platforms don't support this libDir configuration parameter and the library path MUST be provided with an environment variable before executing the scrips.

Where it starts to not make sense is this:

• If I set the environment variable to the correct path, it works
• If I set the environment variable and the libDir configuration parameter to the same correct path, it works
• If I set the environment variable to the correct path, and the libDir configuration parameter to an incorrect path, it does not work
• If I set the environment variable to an incorrect path, and the libDir configuration parameter to a correct path, it does not work

So, it seems like the libDir configuration parameter is taken into account, and in some case take precedence on the environment variable, but ultimately is not used, and is ignored if not passed.

What is the actual logic behind this? The documentation is nowhere near accurate enough for us to understand how we are expected to use the library in applications that are expected to be multi-platform.

And why is the libDir configuration parameter not enough on Linux platforms? Why is it working for every other platform except this specific one?

[sharadraju]

@ericmorand Thank you for raising the issue.
Can you please let us know exactly on which Linux platform you are seeing this issue?
Also do let us know the node-oracledb, Oracle Client and Oracle Database versions.

[cjbj]

libDir can't be used on Linux because the way an Oracle Instant Client library is built on Linux means the use of dlOpen() doesn't work, and results in the DPI-1047 error. Instead apps need to rely on the OS library search path mechanism which relies on LD_LIBRARY_PATH or the use of ldconfig.

While driver owners would like libDir to work, and have approached the owners of the problematic library that is included in Instant Client, it is a tough problem to fix because changing that Instant Client library isn't feasible, and the alternative solution, which is to link Instant Client differently, has some consequences for other users. Maybe someone in Oracle will be brave and will change the way Instant Client is linked, but until then the rule is simple: don't set libDir on Linux.

const oracledb = require('oracledb');

let clientOpts = {};
if (process.platform === 'win32') { 
    clientOpts = { libDir: 'C:\\oracle\\instantclient_xxxx' };
} else if (process.platform === 'darwin') {
    clientOpts = { libDir: process.env.HOME + '/Downloads/instantclient_xxx' };
} // else on other platforms the system library search path
  // must always be set before Node.js is started.

oracledb.initOracleClient(clientOpts);

[ericmorand]

@cjbj thanks for the explanation. Do you know why populating libDir with an incorrect value makes the initialisation fail even though the environnement variable is correctly set. I would expect that, considering your explanation ("libDir can't be used on Linux because the way an Oracle Instant Client library is built on Linux means the use of dlOpen() doesn't work") that libDir would have no effect at all.

[sharadraju]

Just to expand on @cjbj's explanation, populating libDir with an incorrect value fails, because the driver is currently designed to check the value of libDir if it is populated and does not ignore it (Essentially the libDir property value is given precedence from the driver side).

Here is the explanation on what is exactly failing

If I set the environment variable to the correct path, and the libDir configuration parameter to an incorrect path, it does not work -
In this case the driver throws the error
If I set the environment variable to an incorrect path, and the libDir configuration parameter to a correct path, it does not work -
In this case the Oracle Client library throws an error

I checked the documentation on this and it does appear to be slightly confusing. We will get that corrected. The documentation should say something like

Never set ``libDir`` on Linux   and related platforms. Instead you must configure the system library search
  path to include the directory before starting Node.js.

I will discuss internally with the team, if we need to make the change to the driver behavior internally. Can you provide me a use case as to why you need libDir to be ignored in your case? Perhaps you can remove libDir from your application.

[ericmorand]

@sharadraju I don't have an actual use case. I was working on our internal "developer onboarding" documentation about the driver, and was trying multiple things to be sure that I had everything covered.

I think the change that you propose is enough to remove the confusion about libDir. And your explanation about what layer actually fails is perfect for my own curiosity.

Thanks a lot.

[cjbj]

@ericmorand The big question is what is missing from the driver that stops you from using Thin mode?