ID 473065 - Long processing times to make changes to a Material network if the Shader model has a high number of inputs

Problem summary
Long processing times to make changes to a Material network if the Shader model has a high number of inputs

Customer reported version
Mari 4.7v2

Customer reported platform

Multiple

Steps to reproduce

1) Create a custom Shader with a high number of inputs, or install Renderman for Mari to use the pxrSurface Shader

2) Create 10 or more Material nodes, configured for the custom or pxrSurface shader model

3) Chain the Material nodes together with Multi-Channel Merge nodes

4) Create a new Material node and connect it to the network with a Multi-Channel Merge node

Expected behaviour
The new Material node should be connected to the network.

Actual behaviour
The new Material node connects to the network, but it takes a long time, during which Mari is unresponsive.

The more nodes that are connected to the network, the longer the processing time to add or remove further Material nodes.

Using a Shader model with more inputs also increases this processing time.

Workaround
To save time making changes to large Material networks, parts of the node network can be worked on in isolation before connecting everything at the end.

Reproduced by support

This bug has been reproduced in:
Mari 4.7v2 - Windows 10 - CentOS 7.7

Mari 4.7v1 - Windows 10

Mari 4.6v1 - Windows 10

Mari 4.5v1 - Windows 10 - CentOS 7.7

Earliest version tested
Mari 4.5v1 - This feature did not exist before this version