3.7. QuickJS
Configure QuickJS Javascript Engine.
QuickJS is a new Javascript Engine installed alongside the default Spidermonkey engine. It’s disabled by default, but may be enabled via configuration settings.
The configuration toggle to enable and disable QuickJS by default is in
couchdb js_engine section.
To help evaluate design doc compatibility, without the penalty of resetting all the views on a cluster, there is a scanner plugin, which will traverse databases and design docs, compile and then execute some of the view functions using both engines and report incompatibilities.
Added in version 3.4.
3.7.1. QuickJS Options
- [quickjs]
- memory_limit_bytes
Set QuickJS memory limit in bytes. The default is
undefinedand the built-in C default of 64MB is used.[quickjs] memory_limit_bytes = 67108864
- [couch_quickjs_scanner_plugin]
Enable QuickJS Scanner plugin in couch_scanner_plugins couch_scanner_plugins section.
- max_ddocs
Limit the number of design docs processed per database.
[couch_quickjs_scanner_plugin] max_ddocs = 100
- max_shards
Limit the number of shards processed per database.
[couch_quickjs_scanner_plugin] max_shards = 4
- max_docs
Limit the number of documents processed per database. These are the max number of documents sent to the design doc functions.
[couch_quickjs_scanner_plugin] max_docs = 1000
- max_step
Limit the maximum step size when processing docs. Given that total number of documents in a shard as N, if the max_docs is M, then the step S = N / M. Then only every S documents will be sampled and processed.
[couch_quickjs_scanner_plugin] max_step = 1000
- max_batch_items
Maximum document batch size to gather before feeding them through each design doc on both QuickJS and Spidermonkey engines and compare the results.
[couch_quickjs_scanner_plugin] max_batch_items = 100
- max_batch_size
Maximum memory usage for a document batch size.
[couch_quickjs_scanner_plugin] max_batch_size = 16777216