estimate_database_sizes

database_replicator::migration::estimation

Function estimate_database_sizes 

Source 
pub async fn estimate_database_sizes(
    source_url: &str,
    source_client: &Client,
    databases: &[DatabaseInfo],
    filter: &ReplicationFilter,
) -> Result<Vec<DatabaseSizeInfo>>
Expand description

Estimate database sizes and replication times with filtering support

Queries PostgreSQL for database sizes and calculates estimated replication times based on typical dump/restore speeds. Uses a conservative estimate of 20 GB/hour for total replication time (dump + restore).

When table filters are specified, connects to each database to compute the exact size of filtered tables rather than using the entire database size.

§Arguments

  • source_url - Connection URL for the source database cluster
  • source_client - Connected PostgreSQL client to source database
  • databases - List of databases to estimate
  • filter - Replication filter for table inclusion/exclusion

§Returns

Returns a vector of DatabaseSizeInfo with size and time estimates for each database.

§Errors

This function will return an error if:

  • Cannot query database sizes
  • Database connection fails
  • Cannot connect to individual databases for table filtering

§Examples

let url = "postgresql://user:pass@localhost:5432/postgres";
let client = connect(url).await?;
let databases = list_databases(&client).await?;
let filter = ReplicationFilter::empty();
let estimates = estimate_database_sizes(url, &client, &databases, &filter).await?;

for estimate in estimates {
    println!("{}: {} (~{:?})", estimate.name, estimate.size_human, estimate.estimated_duration);
}