stats: added additional mode to --cache-threshold

Added addl logic to remove auto-created index if the `--cache-threshold` arg ends with a 5.

src/cmd/stats.rs

@@ -145,8 +145,10 @@ stats options:
  Set to 0 to suppress caching. 
  Set to 1 to force caching.
  Set to a negative number to automatically create an index
- when the input file size is greater than abs(arg) in bytes
- AND to force caching.
+ when the input file size is greater than abs(arg) in bytes.
+ If the negative number ends with 5, it will delete the index
+ file and the stats cache file after the stats run. Otherwise,
+ the index file and the cache files are kept.
  [default: 5000]
 
 Common options:
@@ -379,6 +381,7 @@ pub fn run(argv: &[&str]) -> CliResult<()> {
 
  let mut compute_stats = true;
  let mut create_cache = args.flag_cache_threshold > 0 || args.flag_stats_binout;
+ let mut autoindex_set = false;
 
  let write_stats_binout = args.flag_stats_binout;
 
@@ -484,8 +487,9 @@ pub fn run(argv: &[&str]) -> CliResult<()> {
 
  // check if flag_cache_threshold is a negative number,
  // if so, set the autoindex_size to absolute of the number
- if args.flag_cache_threshold < 0 {
+ if args.flag_cache_threshold.is_negative() {
  fconfig.autoindex_size = args.flag_cache_threshold.unsigned_abs() as u64;
+ autoindex_set = true;
  }
 
  // we need to count the number of records in the file to calculate sparsity
@@ -544,7 +548,8 @@ pub fn run(argv: &[&str]) -> CliResult<()> {
  }
 
  // ensure create_cache is also true if the user specified --cache-threshold 1
- create_cache = create_cache || args.flag_cache_threshold == 1 || args.flag_cache_threshold < 0;
+ create_cache =
+ create_cache || args.flag_cache_threshold == 1 || args.flag_cache_threshold.is_negative();
 
  wtr.flush()?;
 
@@ -584,6 +589,20 @@ pub fn run(argv: &[&str]) -> CliResult<()> {
  fs::copy(currstats_filename.clone(), stats_pathbuf.clone())?;
  }
 
+ if args.flag_cache_threshold.is_negative() && args.flag_cache_threshold % 10 == -5 {
+ // if the cache threshold is a negative number ending in 5,
+ // delete both the index file and the stats cache file
+ if autoindex_set {
+ let index_file = path.with_extension("csv.idx");
+ log::debug!("deleting index file: {}", index_file.display());
+ if std::fs::remove_file(index_file.clone()).is_err() {
+ // fails silently if it can't remove the index file
+ log::warn!("Could not remove index file: {}", index_file.display());
+ }
+ }
+ create_cache = false;
+ }
+
  if !create_cache {
  // remove the stats cache file
  if fs::remove_file(stats_pathbuf.clone()).is_err() {