System Performance

REDCap generally performs well, but large projects may cause some issues. Our systems have finite resources available to them and large projects may be prone to issues under certain circumstances. We do continually monitor system performance and we do allocate additional resources if and when we can.

Slow Pages

Large projects may experience poor performance when building the record status dashboard or the record home page. Specifically:

Customizations

The Custom Record Label and the Secondary Unique field both will slow down REDCap because there is no caching for these

Data Entry Forms

If a data entry form is ever slow to load, it is almost never due to the server being slow but because of too many fields or too many fields with branching logic

Record Status Dashboard

The Record Status Dashboard may be slow if the project contains a large number of instruments or events. if the default RSD is slow, you can limit the number of records that are displayed or create a custom dashboard that displays a subset of events/instruments.

Reports and Exports Failing

Retrieving, sorting, and filtering records are resource intensive. Some large reports and exports may fail if they run out of memory during processing. This may be dependent on system loading and current memory configurations. There is no easy answer to this problem. Two options are:

Export your data and build a report using an external tool.
Break your report or export into smaller "chunks". (You can merge exports during analysis using analysis tools such as SPSS, Stata or SAS).
Contact the helpdesk. We may be able to suggest a solution or temporarily allocate additional system resources.

Log Page Slow to Load

Early releases of REDCap used a single table to store log records. More recently logging has been restructured to use additional log tables, which reduces the number of records in each table, and therefore improves log performance. However, the initial log table is large and older projects may still have issues. If your logging page is slow and is critical to study operations let us know. If you have an older project we may be able to move your log records to a smaller table and thus solve the problem. However large, busy projects may still run into issues since querying the log tables is a resource intensive process.

Form Logic and Browser Issues

There are known performance and memory-handling issues with Google Chrome and Microsoft Edge browsers. Both these browsers may crash if they run out of memory when displaying large pages. Additionally, there have been reports of REDCap displaying an error message when an instrument contains variables with very large branching logic or calculations containing hundreds of nested IF statements. Under these circumstances, REDCap may display branching logic or calculated field errors even when the logic is technically correct.