Error in Query Entity due to large data in Database

1.  That error message is generic and there are other causes. Are you sure it's related to the volume of data?
2. If it is, then you can use the paging capability to fetch the data in smaller batches. Setting the 'batchSize' to -1 will indeed attempt to fetch all of the data, and you can mitigate this by adding one or more filters, and/or change the 'batchSize' to a number like 10, or 50, or whatever makes sense in the context of your solution

As an example for Stewart's #2, this is typically how I will batch from a!queryEntity() when I need to return a data set larger than a single query can handle:

a!localVariables(
  local!batchSize: 3000,
  local!totalCount: 
  a!queryEntity(
    entity: cons!YOUR_DS_HERE,
    fetchtotalcount: true,
    query: a!query(
      pagingInfo: a!pagingInfo(1,1)
    )
  ).totalCount,
  local!batchCount: ceiling(local!totalCount/local!batchSize),

  a!flatten(
    a!forEach(
      items: 1+enumerate(local!batchCount),
      expression: a!localVariables(
        local!startIndex: fv!item+((fv!index-1)*local!batchSize)-(fv!index-1),
        a!queryEntity(
          entity: cons!YOUR_DS_HERE,
          fetchtotalcount: false,
          query: a!query(
            pagingInfo: a!pagingInfo(local!startIndex,local!batchSize)
          )
        ).data
      )
    )
  )
)

With average amounts of columns I can typically batch 5000 rows at a time, however if your column count grows you may have to lessen this value since the maximum is related to data size, not row count.

This example is designed for a database view which contains the necessary filters built in, however you can add your filters to the a!query() calls on lines 7 and 21 (add the same filter sets for each).