Introduction to Cache

Sharing a ledger of spatial results through Google Drive

Cache stores results by the call that made them. When the result belongs to a place, e.g. a model fitted for one polygon, a ledger is more useful: one .rds file of rows (a polygon plus any columns, including fitted models), from which CacheGeoRead() returns the rows that overlap an area, and CacheGeo() computes only for an area the ledger does not yet cover. See ?CacheGeoLedger.

To share a ledger, create a Google Drive folder, share it “Anyone with the link” as a viewer, and give everyone the folder’s URL as remote. Reading needs no Google login; the file is downloaded only when its md5 differs from the local copy’s. Only the people who write need a login (googledrive::drive_auth()). Two writers at the same time do not lose each other’s rows: CacheGeoWrite() reads the file on Drive again just before writing, and merges again if it changed.

led <- CacheGeoLedger("fitsByPolygon.rds",
                      remote = "https://drive.google.com/drive/folders/<folder id>",
                      destinationPath = "inputs", key = "polygonID")

# anyone: the rows that overlap the study area (an sf object; 0 rows if none)
rows <- CacheGeoRead(led, area = studyArea)

# a writer: replaces the row with the same polygonID, uploads only if the file changed
CacheGeoWrite(led, newRow)

# read, and fit only what is missing
rows <- CacheGeo(led, area = studyArea, compute = function(area) fitThisPolygon(area))

Reproducible workflow

As part of a reproducible workflow, caching of function calls, code chunks, and other elements of a project is a critical component. The objective of a reproducible workflow is is likely that an entire work flow from raw data to publication, decision support, report writing, presentation building etc., could be built and be reproducible anywhere, on any computer, operating system, with any starting conditions, on demand. The reproducible::Cache function is built to work with any R function.

Differences with other approaches

Cache users DBI as a backend, with key functions, dbReadTable, dbRemoveTable, dbSendQuery, dbSendStatement, dbCreateTable and dbAppendTable. These can all be accessed via Cache, showCache, clearCache, and keepCache. It is optimized for speed of transactions, using digest::digest on objects and files. The main function is superficially similar to archivist::cache, which uses digest::digest in all cases to determine whether the arguments are identical in subsequent iterations. It also but does many things that make standard caching with digest::digest don’t work reliably between systems. For these, the function .robustDigest is introduced to make caching transferable between systems. This is relevant for file paths, environments, parallel clusters, functions (which are contained within an environment), and many others (e.g., see ?.robustDigest for methods). Cache also adds important elements like automated tagging and the option to retrieve disk-cached values via stashed objects in memory using memoise::memoise. This means that running Cache 1, 2, and 3 times on the same function will get progressively faster. This can be extremely useful for web apps built with, say shiny.

Function-level caching

Any function can be cached by wrapping Cache around the function call, or by using base pipe |>:

This will be a slight change to a function call, such as: terra::project(raster, crs = terra::crs(newRaster)) to Cache(terra::project(raster, crs = terra::crs(newRaster))) or with the pipe, which may be more convenient as it is easy to add and remove caching in the code base: terra::project(raster, crs = terra::crs(newRaster)) |> Cache()

This is particularly useful for expensive operations.

library(reproducible)
library(data.table)
## 
## Attaching package: 'data.table'
## The following object is masked from 'package:terra':
## 
##     shift
## The following object is masked from 'package:base':
## 
##     %notin%
tmpDir <- file.path(tempfile(), "reproducible_examples", "Cache")
dir.create(tmpDir, recursive = TRUE)

# Source raster with a complete LCC definition
ras <- terra::rast(terra::ext(0, 300, 0, 300), vals = 1:9e4, res = 1)
terra::crs(ras) <- "+proj=lcc +lat_1=60 +lat_2=70 +lat_0=50 +lon_0=-100 +x_0=0 +y_0=0 +datum=WGS84 +units=m +no_defs"

# Target CRS in PROJ form (no EPSG lookup)
newCRS <- "+proj=longlat +datum=WGS84 +no_defs"

# Derive target extent from source extent (no registry lookup)
target_ext <- terra::project(terra::ext(ras), from = terra::crs(ras), to = newCRS)

# Build template with chosen resolution; assign CRS
tmplate <- terra::rast(target_ext, resolution = 0.00001)
terra::crs(tmplate) <- newCRS

# No Cache
system.time(map1 <- terra::project(ras, tmplate, method = "near"))
##    user  system elapsed 
##   0.031   0.000   0.030
# Try with memoise for this example -- for many simple cases, memoising will not be faster
opts <- options("reproducible.useMemoise" = TRUE)
# With Cache -- a little slower the first time because saving to disk
system.time({
  suppressWarnings({
    map1 <- terra::project(ras, tmplate, method = "near") |> 
      Cache(cachePath = tmpDir)
  })
})
## Saved! Cache file: b080b61ea3444bd7.rds; fn: project (and added a memoised copy)
##    user  system elapsed 
##   0.404   0.025   0.432
# faster the second time; improvement depends on size of object and time to run function
system.time({
  map2 <- terra::project(ras, tmplate, method = "near") |> 
    Cache(cachePath = tmpDir)
})
## Object to retrieve (fn: project, b080b61ea3444bd7.rds) ...
## Loaded! Memoised result from previous project call
##    user  system elapsed 
##   0.078   0.001   0.079
options(opts)

all.equal(map1, map2, check.attributes = FALSE) # TRUE
## [1] "Attributes: < Component \".Cache\": Component \"newCache\": 1 element mismatch >"                
## [2] "Attributes: < Component \"pntr\": Component \"origin\": Mean relative difference: 0.0003503788 >"

Caching examples

Basic use

try(clearCache(tmpDir, ask = FALSE), silent = TRUE) # just to make sure it is clear

ranNumsA <- rnorm(10, 16) |> Cache(cachePath = tmpDir)
## Saved! Cache file: aa549dd751b2f26d.rds; fn: rnorm
# All same
ranNumsB <- rnorm(10, 16) |> Cache(cachePath = tmpDir) # recovers cached copy
## Object to retrieve (fn: rnorm, aa549dd751b2f26d.rds) ...
## Loaded! Cached result from previous rnorm call
ranNumsD1 <- Cache(quote(rnorm(n = 10, 16))) |> Cache(cachePath = tmpDir) # recovers cached copy
## No cachePath supplied. Using /tmp/Rtmpv34gxE/reproducible/cache
## Saved! Cache file: aa549dd751b2f26d.rds; fn: rnorm
## Saved! Cache file: 579099707ff597eb.rds; fn: Cache
ranNumsD2 <- Cache(rnorm(n = 10, 16)) |> Cache(cachePath = tmpDir) # recovers cached copy
## No cachePath supplied and getOption('reproducible.cachePath') is inside a temporary directory;
##   this will not persist across R sessions.
## Object to retrieve (fn: rnorm, aa549dd751b2f26d.rds) ...
## Loaded! Cached result from previous rnorm call
## Saved! Cache file: 72d4cb57fcaed7ff.rds; fn: Cache
# pipe
ranNumsD3 <- rnorm(n = 10, 16) |> Cache(cachePath = tmpDir) # recovers cached copy
## Object to retrieve (fn: rnorm, aa549dd751b2f26d.rds) ...
## Loaded! Cached result from previous rnorm call
# Any minor change makes it different
ranNumsE <- rnorm(10, 6) |> Cache(cachePath = tmpDir) # different
## Saved! Cache file: d78b46a2a76d6d80.rds; fn: rnorm

Example 1: Basic cache use with tags

ranNumsA <- rnorm(4) |> Cache(cachePath = tmpDir, userTags = "objectName:a")
## Saved! Cache file: adf21923cd1e50d0.rds; fn: rnorm
ranNumsB <- runif(4) |> Cache(cachePath = tmpDir, userTags = "objectName:b")
## Saved! Cache file: e23cab430872a0ea.rds; fn: runif
showCache(tmpDir, userTags = c("objectName"))
## Cache size:
## Total (including Rasters): 40 bytes
## Selected objects (not including Rasters): 40 bytes
##              cacheId              tagKey                  tagValue
##               <char>              <char>                    <char>
##  1: adf21923cd1e50d0            function                     rnorm
##  2: adf21923cd1e50d0          objectName                         a
##  3: adf21923cd1e50d0            accessed 2026-10-11 20:32:52.74835
##  4: adf21923cd1e50d0             inCloud                     FALSE
##  5: adf21923cd1e50d0   elapsedTimeDigest          0.001810789 secs
##  6: adf21923cd1e50d0           preDigest     .FUN:4f604aa46882b368
##  7: adf21923cd1e50d0           preDigest     mean:c40c00762a0dac94
##  8: adf21923cd1e50d0           preDigest        n:7eef4eae85fd9229
##  9: adf21923cd1e50d0           preDigest       sd:853b1797f54b229c
## 10: adf21923cd1e50d0               class                   numeric
## 11: adf21923cd1e50d0         object.size                        80
## 12: adf21923cd1e50d0            fromDisk                     FALSE
## 13: adf21923cd1e50d0          resultHash                          
## 14: adf21923cd1e50d0 elapsedTimeFirstRun          0.001092672 secs
## 15: e23cab430872a0ea            function                     runif
## 16: e23cab430872a0ea          objectName                         b
## 17: e23cab430872a0ea            accessed 2026-10-11 20:32:52.75559
## 18: e23cab430872a0ea             inCloud                     FALSE
## 19: e23cab430872a0ea   elapsedTimeDigest          0.001781464 secs
## 20: e23cab430872a0ea           preDigest     .FUN:881ec847b7161f3c
## 21: e23cab430872a0ea           preDigest      max:853b1797f54b229c
## 22: e23cab430872a0ea           preDigest      min:c40c00762a0dac94
## 23: e23cab430872a0ea           preDigest        n:7eef4eae85fd9229
## 24: e23cab430872a0ea               class                   numeric
## 25: e23cab430872a0ea         object.size                        80
## 26: e23cab430872a0ea            fromDisk                     FALSE
## 27: e23cab430872a0ea          resultHash                          
## 28: e23cab430872a0ea elapsedTimeFirstRun         0.0009922981 secs
##              cacheId              tagKey                  tagValue
##               <char>              <char>                    <char>
##                    createdDate
##                         <char>
##  1: 2026-10-11 20:32:52.750606
##  2: 2026-10-11 20:32:52.750606
##  3: 2026-10-11 20:32:52.750606
##  4: 2026-10-11 20:32:52.750606
##  5: 2026-10-11 20:32:52.750606
##  6: 2026-10-11 20:32:52.750606
##  7: 2026-10-11 20:32:52.750606
##  8: 2026-10-11 20:32:52.750606
##  9: 2026-10-11 20:32:52.750606
## 10: 2026-10-11 20:32:52.750606
## 11: 2026-10-11 20:32:52.750606
## 12: 2026-10-11 20:32:52.750606
## 13: 2026-10-11 20:32:52.750606
## 14: 2026-10-11 20:32:52.750606
## 15: 2026-10-11 20:32:52.757728
## 16: 2026-10-11 20:32:52.757728
## 17: 2026-10-11 20:32:52.757728
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## 27: 2026-10-11 20:32:52.757728
## 28: 2026-10-11 20:32:52.757728
##                    createdDate
##                         <char>
showCache(tmpDir, userTags = c("^a$")) # regular expression ... "a" exactly
## Cache size:
## Total (including Rasters): 20 bytes
## Selected objects (not including Rasters): 20 bytes
##              cacheId              tagKey                  tagValue
##               <char>              <char>                    <char>
##  1: adf21923cd1e50d0            function                     rnorm
##  2: adf21923cd1e50d0          objectName                         a
##  3: adf21923cd1e50d0            accessed 2026-10-11 20:32:52.74835
##  4: adf21923cd1e50d0             inCloud                     FALSE
##  5: adf21923cd1e50d0   elapsedTimeDigest          0.001810789 secs
##  6: adf21923cd1e50d0           preDigest     .FUN:4f604aa46882b368
##  7: adf21923cd1e50d0           preDigest     mean:c40c00762a0dac94
##  8: adf21923cd1e50d0           preDigest        n:7eef4eae85fd9229
##  9: adf21923cd1e50d0           preDigest       sd:853b1797f54b229c
## 10: adf21923cd1e50d0               class                   numeric
## 11: adf21923cd1e50d0         object.size                        80
## 12: adf21923cd1e50d0            fromDisk                     FALSE
## 13: adf21923cd1e50d0          resultHash                          
## 14: adf21923cd1e50d0 elapsedTimeFirstRun          0.001092672 secs
##                    createdDate
##                         <char>
##  1: 2026-10-11 20:32:52.750606
##  2: 2026-10-11 20:32:52.750606
##  3: 2026-10-11 20:32:52.750606
##  4: 2026-10-11 20:32:52.750606
##  5: 2026-10-11 20:32:52.750606
##  6: 2026-10-11 20:32:52.750606
##  7: 2026-10-11 20:32:52.750606
##  8: 2026-10-11 20:32:52.750606
##  9: 2026-10-11 20:32:52.750606
## 10: 2026-10-11 20:32:52.750606
## 11: 2026-10-11 20:32:52.750606
## 12: 2026-10-11 20:32:52.750606
## 13: 2026-10-11 20:32:52.750606
## 14: 2026-10-11 20:32:52.750606
showCache(tmpDir, userTags = c("runif")) # show only cached objects made during runif call
## Cache size:
## Total (including Rasters): 20 bytes
## Selected objects (not including Rasters): 20 bytes
##              cacheId              tagKey                  tagValue
##               <char>              <char>                    <char>
##  1: e23cab430872a0ea            function                     runif
##  2: e23cab430872a0ea          objectName                         b
##  3: e23cab430872a0ea            accessed 2026-10-11 20:32:52.75559
##  4: e23cab430872a0ea             inCloud                     FALSE
##  5: e23cab430872a0ea   elapsedTimeDigest          0.001781464 secs
##  6: e23cab430872a0ea           preDigest     .FUN:881ec847b7161f3c
##  7: e23cab430872a0ea           preDigest      max:853b1797f54b229c
##  8: e23cab430872a0ea           preDigest      min:c40c00762a0dac94
##  9: e23cab430872a0ea           preDigest        n:7eef4eae85fd9229
## 10: e23cab430872a0ea               class                   numeric
## 11: e23cab430872a0ea         object.size                        80
## 12: e23cab430872a0ea            fromDisk                     FALSE
## 13: e23cab430872a0ea          resultHash                          
## 14: e23cab430872a0ea elapsedTimeFirstRun         0.0009922981 secs
##                    createdDate
##                         <char>
##  1: 2026-10-11 20:32:52.757728
##  2: 2026-10-11 20:32:52.757728
##  3: 2026-10-11 20:32:52.757728
##  4: 2026-10-11 20:32:52.757728
##  5: 2026-10-11 20:32:52.757728
##  6: 2026-10-11 20:32:52.757728
##  7: 2026-10-11 20:32:52.757728
##  8: 2026-10-11 20:32:52.757728
##  9: 2026-10-11 20:32:52.757728
## 10: 2026-10-11 20:32:52.757728
## 11: 2026-10-11 20:32:52.757728
## 12: 2026-10-11 20:32:52.757728
## 13: 2026-10-11 20:32:52.757728
## 14: 2026-10-11 20:32:52.757728
clearCache(tmpDir, userTags = c("runif"), ask = FALSE) # remove only cached objects made during runif call
## Cache size:
## Total (including Rasters): 20 bytes
## Selected objects (not including Rasters): 20 bytes
showCache(tmpDir) # all
## Cache size:
## Total (including Rasters): 482 bytes
## Selected objects (not including Rasters): 482 bytes
##              cacheId              tagKey                         tagValue
##               <char>              <char>                           <char>
##  1: 579099707ff597eb            function                            Cache
##  2: 579099707ff597eb            accessed        2026-10-11 20:32:52.68523
##  3: 579099707ff597eb             inCloud                            FALSE
##  4: 579099707ff597eb   elapsedTimeDigest                 0.002880812 secs
##  5: 579099707ff597eb           preDigest  .cacheChaining:71681d621365dfd7
##  6: 579099707ff597eb           preDigest     .cacheExtra:c85d88fc56f4e042
##  7: 579099707ff597eb           preDigest            .FUN:1b670f52e1b13bd1
##  8: 579099707ff597eb           preDigest   .functionName:c85d88fc56f4e042
##  9: 579099707ff597eb           preDigest            conn:118387d5d48f757d
## 10: 579099707ff597eb           preDigest             drv:9ce9a83896bf68a1
## 11: 579099707ff597eb           preDigest cacheSaveFormat:cf2828ea967d53e7
## 12: 579099707ff597eb           preDigest          dryRun:e9aac936a0e8f6ae
## 13: 579099707ff597eb           preDigest             FUN:265d86c3bd130de5
## 14: 579099707ff597eb               class                             call
## 15: 579099707ff597eb         object.size                             1320
## 16: 579099707ff597eb            fromDisk                            FALSE
## 17: 579099707ff597eb          resultHash                                 
## 18: 579099707ff597eb elapsedTimeFirstRun                 0.009168148 secs
## 19: 72d4cb57fcaed7ff            function                            Cache
## 20: 72d4cb57fcaed7ff            accessed        2026-10-11 20:32:52.70103
## 21: 72d4cb57fcaed7ff             inCloud                            FALSE
## 22: 72d4cb57fcaed7ff   elapsedTimeDigest                 0.002597809 secs
## 23: 72d4cb57fcaed7ff           preDigest  .cacheChaining:71681d621365dfd7
## 24: 72d4cb57fcaed7ff           preDigest     .cacheExtra:c85d88fc56f4e042
## 25: 72d4cb57fcaed7ff           preDigest            .FUN:1b670f52e1b13bd1
## 26: 72d4cb57fcaed7ff           preDigest   .functionName:c85d88fc56f4e042
## 27: 72d4cb57fcaed7ff           preDigest            conn:118387d5d48f757d
## 28: 72d4cb57fcaed7ff           preDigest             drv:9ce9a83896bf68a1
## 29: 72d4cb57fcaed7ff           preDigest cacheSaveFormat:cf2828ea967d53e7
## 30: 72d4cb57fcaed7ff           preDigest          dryRun:e9aac936a0e8f6ae
## 31: 72d4cb57fcaed7ff           preDigest             FUN:7e42fc6cf6296e60
## 32: 72d4cb57fcaed7ff               class                          numeric
## 33: 72d4cb57fcaed7ff         object.size                              176
## 34: 72d4cb57fcaed7ff            fromDisk                            FALSE
## 35: 72d4cb57fcaed7ff          resultHash                                 
## 36: 72d4cb57fcaed7ff elapsedTimeFirstRun                 0.008151054 secs
## 37: aa549dd751b2f26d            function                            rnorm
## 38: aa549dd751b2f26d            accessed        2026-10-11 20:32:52.66451
## 39: aa549dd751b2f26d             inCloud                            FALSE
## 40: aa549dd751b2f26d   elapsedTimeDigest                 0.001981258 secs
## 41: aa549dd751b2f26d           preDigest            .FUN:4f604aa46882b368
## 42: aa549dd751b2f26d           preDigest            mean:15620f138033a66c
## 43: aa549dd751b2f26d           preDigest               n:c5775c3b366fb719
## 44: aa549dd751b2f26d           preDigest              sd:853b1797f54b229c
## 45: aa549dd751b2f26d               class                          numeric
## 46: aa549dd751b2f26d         object.size                              176
## 47: aa549dd751b2f26d            fromDisk                            FALSE
## 48: aa549dd751b2f26d          resultHash                                 
## 49: aa549dd751b2f26d elapsedTimeFirstRun                 0.001411676 secs
## 50: aa549dd751b2f26d            accessed        2026-10-11 20:32:52.67911
## 51: aa549dd751b2f26d            accessed        2026-10-11 20:32:52.71726
## 52: adf21923cd1e50d0            function                            rnorm
## 53: adf21923cd1e50d0          objectName                                a
## 54: adf21923cd1e50d0            accessed        2026-10-11 20:32:52.74835
## 55: adf21923cd1e50d0             inCloud                            FALSE
## 56: adf21923cd1e50d0   elapsedTimeDigest                 0.001810789 secs
## 57: adf21923cd1e50d0           preDigest            .FUN:4f604aa46882b368
## 58: adf21923cd1e50d0           preDigest            mean:c40c00762a0dac94
## 59: adf21923cd1e50d0           preDigest               n:7eef4eae85fd9229
## 60: adf21923cd1e50d0           preDigest              sd:853b1797f54b229c
## 61: adf21923cd1e50d0               class                          numeric
## 62: adf21923cd1e50d0         object.size                               80
## 63: adf21923cd1e50d0            fromDisk                            FALSE
## 64: adf21923cd1e50d0          resultHash                                 
## 65: adf21923cd1e50d0 elapsedTimeFirstRun                 0.001092672 secs
## 66: d78b46a2a76d6d80            function                            rnorm
## 67: d78b46a2a76d6d80            accessed        2026-10-11 20:32:52.72202
## 68: d78b46a2a76d6d80             inCloud                            FALSE
## 69: d78b46a2a76d6d80   elapsedTimeDigest                 0.001711369 secs
## 70: d78b46a2a76d6d80           preDigest            .FUN:4f604aa46882b368
## 71: d78b46a2a76d6d80           preDigest            mean:152602b8ff81e5bb
## 72: d78b46a2a76d6d80           preDigest               n:c5775c3b366fb719
## 73: d78b46a2a76d6d80           preDigest              sd:853b1797f54b229c
## 74: d78b46a2a76d6d80               class                          numeric
## 75: d78b46a2a76d6d80         object.size                              176
## 76: d78b46a2a76d6d80            fromDisk                            FALSE
## 77: d78b46a2a76d6d80          resultHash                                 
## 78: d78b46a2a76d6d80 elapsedTimeFirstRun                0.0008971691 secs
##              cacheId              tagKey                         tagValue
##               <char>              <char>                           <char>
##                    createdDate
##                         <char>
##  1: 2026-10-11 20:32:52.695629
##  2: 2026-10-11 20:32:52.695629
##  3: 2026-10-11 20:32:52.695629
##  4: 2026-10-11 20:32:52.695629
##  5: 2026-10-11 20:32:52.695629
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## 19: 2026-10-11 20:32:52.710537
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## 33: 2026-10-11 20:32:52.710537
## 34: 2026-10-11 20:32:52.710537
## 35: 2026-10-11 20:32:52.710537
## 36: 2026-10-11 20:32:52.710537
## 37: 2026-10-11 20:32:52.667533
## 38: 2026-10-11 20:32:52.667533
## 39: 2026-10-11 20:32:52.667533
## 40: 2026-10-11 20:32:52.667533
## 41: 2026-10-11 20:32:52.667533
## 42: 2026-10-11 20:32:52.667533
## 43: 2026-10-11 20:32:52.667533
## 44: 2026-10-11 20:32:52.667533
## 45: 2026-10-11 20:32:52.667533
## 46: 2026-10-11 20:32:52.667533
## 47: 2026-10-11 20:32:52.667533
## 48: 2026-10-11 20:32:52.667533
## 49: 2026-10-11 20:32:52.667533
## 50: 2026-10-11 20:32:52.679197
## 51: 2026-10-11 20:32:52.717351
## 52: 2026-10-11 20:32:52.750606
## 53: 2026-10-11 20:32:52.750606
## 54: 2026-10-11 20:32:52.750606
## 55: 2026-10-11 20:32:52.750606
## 56: 2026-10-11 20:32:52.750606
## 57: 2026-10-11 20:32:52.750606
## 58: 2026-10-11 20:32:52.750606
## 59: 2026-10-11 20:32:52.750606
## 60: 2026-10-11 20:32:52.750606
## 61: 2026-10-11 20:32:52.750606
## 62: 2026-10-11 20:32:52.750606
## 63: 2026-10-11 20:32:52.750606
## 64: 2026-10-11 20:32:52.750606
## 65: 2026-10-11 20:32:52.750606
## 66: 2026-10-11 20:32:52.724049
## 67: 2026-10-11 20:32:52.724049
## 68: 2026-10-11 20:32:52.724049
## 69: 2026-10-11 20:32:52.724049
## 70: 2026-10-11 20:32:52.724049
## 71: 2026-10-11 20:32:52.724049
## 72: 2026-10-11 20:32:52.724049
## 73: 2026-10-11 20:32:52.724049
## 74: 2026-10-11 20:32:52.724049
## 75: 2026-10-11 20:32:52.724049
## 76: 2026-10-11 20:32:52.724049
## 77: 2026-10-11 20:32:52.724049
## 78: 2026-10-11 20:32:52.724049
##                    createdDate
##                         <char>
clearCache(tmpDir, ask = FALSE)

Example 2: using the “accessed” tag

ranNumsA <- rnorm(4) |> Cache(cachePath = tmpDir, userTags = "objectName:a")
## Saved! Cache file: adf21923cd1e50d0.rds; fn: rnorm
ranNumsB <- runif(4) |> Cache(cachePath = tmpDir, userTags = "objectName:b")
## Saved! Cache file: e23cab430872a0ea.rds; fn: runif
# access it again, from Cache
Sys.sleep(1)
ranNumsA <- rnorm(4) |> Cache(cachePath = tmpDir, userTags = "objectName:a")
## Object to retrieve (fn: rnorm, adf21923cd1e50d0.rds) ...
## Loaded! Cached result from previous rnorm call
wholeCache <- showCache(tmpDir)
## Cache size:
## Total (including Rasters): 40 bytes
## Selected objects (not including Rasters): 40 bytes
# keep only items accessed "recently" (i.e., only objectName:a)
onlyRecentlyAccessed <- showCache(tmpDir, userTags = max(wholeCache[tagKey == "accessed"]$tagValue))
## Cache size:
## Total (including Rasters): 40 bytes
## Selected objects (not including Rasters): 40 bytes
# inverse join with 2 data.tables ... using: a[!b]
# i.e., return all of wholeCache that was not recently accessed
#   Note: the two different ways to access -- old way with "artifact" will be deprecated
toRemove <- unique(wholeCache[!onlyRecentlyAccessed, on = "cacheId"], by = "cacheId")$cacheId
clearCache(tmpDir, toRemove, ask = FALSE) # remove ones not recently accessed
## Cache size:
## Total (including Rasters): 40 bytes
## Selected objects (not including Rasters): 40 bytes
showCache(tmpDir) # still has more recently accessed
## Empty data.table (0 rows and 4 cols): cacheId,tagKey,tagValue,createdDate

Example 3: using keepCache

keepCache does the same as previous example, but more simply.

ranNumsA <- rnorm(4) |> Cache(cachePath = tmpDir, userTags = "objectName:a")
## Saved! Cache file: adf21923cd1e50d0.rds; fn: rnorm
ranNumsB <- Cache(runif(4)) |> Cache(cachePath = tmpDir, userTags = "objectName:b")
## No cachePath supplied and getOption('reproducible.cachePath') is inside a temporary directory;
##   this will not persist across R sessions.
## Saved! Cache file: e23cab430872a0ea.rds; fn: runif
## Saved! Cache file: 2b81e4e8bd0f2f53.rds; fn: Cache
# keep only those cached items from the last 24 hours
oneDay <- 60 * 60 * 24
keepCache(tmpDir, after = Sys.time() - oneDay, ask = FALSE)
## Nothing to remove; keeping all
##              cacheId              tagKey                         tagValue
##               <char>              <char>                           <char>
##  1: 2b81e4e8bd0f2f53            function                            Cache
##  2: 2b81e4e8bd0f2f53          objectName                                b
##  3: 2b81e4e8bd0f2f53            accessed        2026-10-11 20:32:53.92479
##  4: 2b81e4e8bd0f2f53             inCloud                            FALSE
##  5: 2b81e4e8bd0f2f53   elapsedTimeDigest                 0.002732038 secs
##  6: 2b81e4e8bd0f2f53           preDigest  .cacheChaining:71681d621365dfd7
##  7: 2b81e4e8bd0f2f53           preDigest     .cacheExtra:c85d88fc56f4e042
##  8: 2b81e4e8bd0f2f53           preDigest            .FUN:1b670f52e1b13bd1
##  9: 2b81e4e8bd0f2f53           preDigest   .functionName:c85d88fc56f4e042
## 10: 2b81e4e8bd0f2f53           preDigest            conn:118387d5d48f757d
## 11: 2b81e4e8bd0f2f53           preDigest             drv:9ce9a83896bf68a1
## 12: 2b81e4e8bd0f2f53           preDigest cacheSaveFormat:cf2828ea967d53e7
## 13: 2b81e4e8bd0f2f53           preDigest          dryRun:e9aac936a0e8f6ae
## 14: 2b81e4e8bd0f2f53           preDigest             FUN:09c45d5cc048c64a
## 15: 2b81e4e8bd0f2f53               class                          numeric
## 16: 2b81e4e8bd0f2f53         object.size                             1008
## 17: 2b81e4e8bd0f2f53            fromDisk                            FALSE
## 18: 2b81e4e8bd0f2f53          resultHash                                 
## 19: 2b81e4e8bd0f2f53 elapsedTimeFirstRun                 0.008973837 secs
## 20: adf21923cd1e50d0            function                            rnorm
## 21: adf21923cd1e50d0          objectName                                a
## 22: adf21923cd1e50d0            accessed        2026-10-11 20:32:53.91628
## 23: adf21923cd1e50d0             inCloud                            FALSE
## 24: adf21923cd1e50d0   elapsedTimeDigest                  0.00201416 secs
## 25: adf21923cd1e50d0           preDigest            .FUN:4f604aa46882b368
## 26: adf21923cd1e50d0           preDigest            mean:c40c00762a0dac94
## 27: adf21923cd1e50d0           preDigest               n:7eef4eae85fd9229
## 28: adf21923cd1e50d0           preDigest              sd:853b1797f54b229c
## 29: adf21923cd1e50d0               class                          numeric
## 30: adf21923cd1e50d0         object.size                               80
## 31: adf21923cd1e50d0            fromDisk                            FALSE
## 32: adf21923cd1e50d0          resultHash                                 
## 33: adf21923cd1e50d0 elapsedTimeFirstRun                 0.001196384 secs
##              cacheId              tagKey                         tagValue
##               <char>              <char>                           <char>
##                    createdDate
##                         <char>
##  1: 2026-10-11 20:32:53.935019
##  2: 2026-10-11 20:32:53.935019
##  3: 2026-10-11 20:32:53.935019
##  4: 2026-10-11 20:32:53.935019
##  5: 2026-10-11 20:32:53.935019
##  6: 2026-10-11 20:32:53.935019
##  7: 2026-10-11 20:32:53.935019
##  8: 2026-10-11 20:32:53.935019
##  9: 2026-10-11 20:32:53.935019
## 10: 2026-10-11 20:32:53.935019
## 11: 2026-10-11 20:32:53.935019
## 12: 2026-10-11 20:32:53.935019
## 13: 2026-10-11 20:32:53.935019
## 14: 2026-10-11 20:32:53.935019
## 15: 2026-10-11 20:32:53.935019
## 16: 2026-10-11 20:32:53.935019
## 17: 2026-10-11 20:32:53.935019
## 18: 2026-10-11 20:32:53.935019
## 19: 2026-10-11 20:32:53.935019
## 20: 2026-10-11 20:32:53.918721
## 21: 2026-10-11 20:32:53.918721
## 22: 2026-10-11 20:32:53.918721
## 23: 2026-10-11 20:32:53.918721
## 24: 2026-10-11 20:32:53.918721
## 25: 2026-10-11 20:32:53.918721
## 26: 2026-10-11 20:32:53.918721
## 27: 2026-10-11 20:32:53.918721
## 28: 2026-10-11 20:32:53.918721
## 29: 2026-10-11 20:32:53.918721
## 30: 2026-10-11 20:32:53.918721
## 31: 2026-10-11 20:32:53.918721
## 32: 2026-10-11 20:32:53.918721
## 33: 2026-10-11 20:32:53.918721
##                    createdDate
##                         <char>
# Keep all Cache items created with an rnorm() call
keepCache(tmpDir, userTags = "rnorm", ask = FALSE)
##              cacheId              tagKey                  tagValue
##               <char>              <char>                    <char>
##  1: adf21923cd1e50d0            function                     rnorm
##  2: adf21923cd1e50d0          objectName                         a
##  3: adf21923cd1e50d0            accessed 2026-10-11 20:32:53.91628
##  4: adf21923cd1e50d0             inCloud                     FALSE
##  5: adf21923cd1e50d0   elapsedTimeDigest           0.00201416 secs
##  6: adf21923cd1e50d0           preDigest     .FUN:4f604aa46882b368
##  7: adf21923cd1e50d0           preDigest     mean:c40c00762a0dac94
##  8: adf21923cd1e50d0           preDigest        n:7eef4eae85fd9229
##  9: adf21923cd1e50d0           preDigest       sd:853b1797f54b229c
## 10: adf21923cd1e50d0               class                   numeric
## 11: adf21923cd1e50d0         object.size                        80
## 12: adf21923cd1e50d0            fromDisk                     FALSE
## 13: adf21923cd1e50d0          resultHash                          
## 14: adf21923cd1e50d0 elapsedTimeFirstRun          0.001196384 secs
##                    createdDate
##                         <char>
##  1: 2026-10-11 20:32:53.918721
##  2: 2026-10-11 20:32:53.918721
##  3: 2026-10-11 20:32:53.918721
##  4: 2026-10-11 20:32:53.918721
##  5: 2026-10-11 20:32:53.918721
##  6: 2026-10-11 20:32:53.918721
##  7: 2026-10-11 20:32:53.918721
##  8: 2026-10-11 20:32:53.918721
##  9: 2026-10-11 20:32:53.918721
## 10: 2026-10-11 20:32:53.918721
## 11: 2026-10-11 20:32:53.918721
## 12: 2026-10-11 20:32:53.918721
## 13: 2026-10-11 20:32:53.918721
## 14: 2026-10-11 20:32:53.918721
showCache(tmpDir)
## Cache size:
## Total (including Rasters): 20 bytes
## Selected objects (not including Rasters): 20 bytes
##              cacheId              tagKey                  tagValue
##               <char>              <char>                    <char>
##  1: adf21923cd1e50d0            function                     rnorm
##  2: adf21923cd1e50d0          objectName                         a
##  3: adf21923cd1e50d0            accessed 2026-10-11 20:32:53.91628
##  4: adf21923cd1e50d0             inCloud                     FALSE
##  5: adf21923cd1e50d0   elapsedTimeDigest           0.00201416 secs
##  6: adf21923cd1e50d0           preDigest     .FUN:4f604aa46882b368
##  7: adf21923cd1e50d0           preDigest     mean:c40c00762a0dac94
##  8: adf21923cd1e50d0           preDigest        n:7eef4eae85fd9229
##  9: adf21923cd1e50d0           preDigest       sd:853b1797f54b229c
## 10: adf21923cd1e50d0               class                   numeric
## 11: adf21923cd1e50d0         object.size                        80
## 12: adf21923cd1e50d0            fromDisk                     FALSE
## 13: adf21923cd1e50d0          resultHash                          
## 14: adf21923cd1e50d0 elapsedTimeFirstRun          0.001196384 secs
##                    createdDate
##                         <char>
##  1: 2026-10-11 20:32:53.918721
##  2: 2026-10-11 20:32:53.918721
##  3: 2026-10-11 20:32:53.918721
##  4: 2026-10-11 20:32:53.918721
##  5: 2026-10-11 20:32:53.918721
##  6: 2026-10-11 20:32:53.918721
##  7: 2026-10-11 20:32:53.918721
##  8: 2026-10-11 20:32:53.918721
##  9: 2026-10-11 20:32:53.918721
## 10: 2026-10-11 20:32:53.918721
## 11: 2026-10-11 20:32:53.918721
## 12: 2026-10-11 20:32:53.918721
## 13: 2026-10-11 20:32:53.918721
## 14: 2026-10-11 20:32:53.918721
# Remove all Cache items that happened within a rnorm() call
clearCache(tmpDir, userTags = "rnorm", ask = FALSE)
## Cache size:
## Total (including Rasters): 20 bytes
## Selected objects (not including Rasters): 20 bytes
showCache(tmpDir) ## empty
## Empty data.table (0 rows and 4 cols): cacheId,tagKey,tagValue,createdDate
# Also, can set a time before caching happens and remove based on this
#  --> a useful, simple way to control Cache
ranNumsA <- rnorm(4) |> Cache(cachePath = tmpDir, userTags = "objectName:a")
## Saved! Cache file: adf21923cd1e50d0.rds; fn: rnorm
startTime <- Sys.time()
Sys.sleep(1)
ranNumsB <- rnorm(5) |> Cache(cachePath = tmpDir, userTags = "objectName:b")
## Saved! Cache file: 438a3028a4570cf9.rds; fn: rnorm
keepCache(tmpDir, after = startTime, ask = FALSE) # keep only those newer than startTime
##              cacheId              tagKey                  tagValue
##               <char>              <char>                    <char>
##  1: 438a3028a4570cf9            function                     rnorm
##  2: 438a3028a4570cf9          objectName                         b
##  3: 438a3028a4570cf9            accessed 2026-10-11 20:32:55.00155
##  4: 438a3028a4570cf9             inCloud                     FALSE
##  5: 438a3028a4570cf9   elapsedTimeDigest          0.002136946 secs
##  6: 438a3028a4570cf9           preDigest     .FUN:4f604aa46882b368
##  7: 438a3028a4570cf9           preDigest     mean:c40c00762a0dac94
##  8: 438a3028a4570cf9           preDigest        n:a4f076b3db622faf
##  9: 438a3028a4570cf9           preDigest       sd:853b1797f54b229c
## 10: 438a3028a4570cf9               class                   numeric
## 11: 438a3028a4570cf9         object.size                        96
## 12: 438a3028a4570cf9            fromDisk                     FALSE
## 13: 438a3028a4570cf9          resultHash                          
## 14: 438a3028a4570cf9 elapsedTimeFirstRun          0.001274824 secs
##                    createdDate
##                         <char>
##  1: 2026-10-11 20:32:55.004119
##  2: 2026-10-11 20:32:55.004119
##  3: 2026-10-11 20:32:55.004119
##  4: 2026-10-11 20:32:55.004119
##  5: 2026-10-11 20:32:55.004119
##  6: 2026-10-11 20:32:55.004119
##  7: 2026-10-11 20:32:55.004119
##  8: 2026-10-11 20:32:55.004119
##  9: 2026-10-11 20:32:55.004119
## 10: 2026-10-11 20:32:55.004119
## 11: 2026-10-11 20:32:55.004119
## 12: 2026-10-11 20:32:55.004119
## 13: 2026-10-11 20:32:55.004119
## 14: 2026-10-11 20:32:55.004119
clearCache(tmpDir, ask = FALSE)

Example 4: searching for multiple objects in the cache

# default userTags is "and" matching; for "or" matching use |
ranNumsA <- runif(4) |> Cache(cachePath = tmpDir, userTags = "objectName:a")
## Saved! Cache file: e23cab430872a0ea.rds; fn: runif
ranNumsB <- rnorm(4) |> Cache(cachePath = tmpDir, userTags = "objectName:b")
## Saved! Cache file: adf21923cd1e50d0.rds; fn: rnorm
# show all objects (runif and rnorm in this case)
showCache(tmpDir)
## Cache size:
## Total (including Rasters): 40 bytes
## Selected objects (not including Rasters): 40 bytes
##              cacheId              tagKey                  tagValue
##               <char>              <char>                    <char>
##  1: adf21923cd1e50d0            function                     rnorm
##  2: adf21923cd1e50d0          objectName                         b
##  3: adf21923cd1e50d0            accessed 2026-10-11 20:32:55.06025
##  4: adf21923cd1e50d0             inCloud                     FALSE
##  5: adf21923cd1e50d0   elapsedTimeDigest          0.001813889 secs
##  6: adf21923cd1e50d0           preDigest     .FUN:4f604aa46882b368
##  7: adf21923cd1e50d0           preDigest     mean:c40c00762a0dac94
##  8: adf21923cd1e50d0           preDigest        n:7eef4eae85fd9229
##  9: adf21923cd1e50d0           preDigest       sd:853b1797f54b229c
## 10: adf21923cd1e50d0               class                   numeric
## 11: adf21923cd1e50d0         object.size                        80
## 12: adf21923cd1e50d0            fromDisk                     FALSE
## 13: adf21923cd1e50d0          resultHash                          
## 14: adf21923cd1e50d0 elapsedTimeFirstRun         0.0009953976 secs
## 15: e23cab430872a0ea            function                     runif
## 16: e23cab430872a0ea          objectName                         a
## 17: e23cab430872a0ea            accessed 2026-10-11 20:32:55.05275
## 18: e23cab430872a0ea             inCloud                     FALSE
## 19: e23cab430872a0ea   elapsedTimeDigest          0.001894712 secs
## 20: e23cab430872a0ea           preDigest     .FUN:881ec847b7161f3c
## 21: e23cab430872a0ea           preDigest      max:853b1797f54b229c
## 22: e23cab430872a0ea           preDigest      min:c40c00762a0dac94
## 23: e23cab430872a0ea           preDigest        n:7eef4eae85fd9229
## 24: e23cab430872a0ea               class                   numeric
## 25: e23cab430872a0ea         object.size                        80
## 26: e23cab430872a0ea            fromDisk                     FALSE
## 27: e23cab430872a0ea          resultHash                          
## 28: e23cab430872a0ea elapsedTimeFirstRun          0.001132488 secs
##              cacheId              tagKey                  tagValue
##               <char>              <char>                    <char>
##                    createdDate
##                         <char>
##  1: 2026-10-11 20:32:55.062466
##  2: 2026-10-11 20:32:55.062466
##  3: 2026-10-11 20:32:55.062466
##  4: 2026-10-11 20:32:55.062466
##  5: 2026-10-11 20:32:55.062466
##  6: 2026-10-11 20:32:55.062466
##  7: 2026-10-11 20:32:55.062466
##  8: 2026-10-11 20:32:55.062466
##  9: 2026-10-11 20:32:55.062466
## 10: 2026-10-11 20:32:55.062466
## 11: 2026-10-11 20:32:55.062466
## 12: 2026-10-11 20:32:55.062466
## 13: 2026-10-11 20:32:55.062466
## 14: 2026-10-11 20:32:55.062466
## 15: 2026-10-11 20:32:55.055096
## 16: 2026-10-11 20:32:55.055096
## 17: 2026-10-11 20:32:55.055096
## 18: 2026-10-11 20:32:55.055096
## 19: 2026-10-11 20:32:55.055096
## 20: 2026-10-11 20:32:55.055096
## 21: 2026-10-11 20:32:55.055096
## 22: 2026-10-11 20:32:55.055096
## 23: 2026-10-11 20:32:55.055096
## 24: 2026-10-11 20:32:55.055096
## 25: 2026-10-11 20:32:55.055096
## 26: 2026-10-11 20:32:55.055096
## 27: 2026-10-11 20:32:55.055096
## 28: 2026-10-11 20:32:55.055096
##                    createdDate
##                         <char>
# show objects that are both runif and rnorm
# (i.e., none in this case, because objecs are either or, not both)
showCache(tmpDir, userTags = c("runif", "rnorm")) ## empty
## Cache size:
## Total (including Rasters): 0 bytes
## Selected objects (not including Rasters): 0 bytes
## Empty data.table (0 rows and 4 cols): cacheId,tagKey,tagValue,createdDate
# show objects that are either runif or rnorm ("or" search)
showCache(tmpDir, userTags = "runif|rnorm")
## Cache size:
## Total (including Rasters): 40 bytes
## Selected objects (not including Rasters): 40 bytes
##              cacheId              tagKey                  tagValue
##               <char>              <char>                    <char>
##  1: adf21923cd1e50d0            function                     rnorm
##  2: adf21923cd1e50d0          objectName                         b
##  3: adf21923cd1e50d0            accessed 2026-10-11 20:32:55.06025
##  4: adf21923cd1e50d0             inCloud                     FALSE
##  5: adf21923cd1e50d0   elapsedTimeDigest          0.001813889 secs
##  6: adf21923cd1e50d0           preDigest     .FUN:4f604aa46882b368
##  7: adf21923cd1e50d0           preDigest     mean:c40c00762a0dac94
##  8: adf21923cd1e50d0           preDigest        n:7eef4eae85fd9229
##  9: adf21923cd1e50d0           preDigest       sd:853b1797f54b229c
## 10: adf21923cd1e50d0               class                   numeric
## 11: adf21923cd1e50d0         object.size                        80
## 12: adf21923cd1e50d0            fromDisk                     FALSE
## 13: adf21923cd1e50d0          resultHash                          
## 14: adf21923cd1e50d0 elapsedTimeFirstRun         0.0009953976 secs
## 15: e23cab430872a0ea            function                     runif
## 16: e23cab430872a0ea          objectName                         a
## 17: e23cab430872a0ea            accessed 2026-10-11 20:32:55.05275
## 18: e23cab430872a0ea             inCloud                     FALSE
## 19: e23cab430872a0ea   elapsedTimeDigest          0.001894712 secs
## 20: e23cab430872a0ea           preDigest     .FUN:881ec847b7161f3c
## 21: e23cab430872a0ea           preDigest      max:853b1797f54b229c
## 22: e23cab430872a0ea           preDigest      min:c40c00762a0dac94
## 23: e23cab430872a0ea           preDigest        n:7eef4eae85fd9229
## 24: e23cab430872a0ea               class                   numeric
## 25: e23cab430872a0ea         object.size                        80
## 26: e23cab430872a0ea            fromDisk                     FALSE
## 27: e23cab430872a0ea          resultHash                          
## 28: e23cab430872a0ea elapsedTimeFirstRun          0.001132488 secs
##              cacheId              tagKey                  tagValue
##               <char>              <char>                    <char>
##                    createdDate
##                         <char>
##  1: 2026-10-11 20:32:55.062466
##  2: 2026-10-11 20:32:55.062466
##  3: 2026-10-11 20:32:55.062466
##  4: 2026-10-11 20:32:55.062466
##  5: 2026-10-11 20:32:55.062466
##  6: 2026-10-11 20:32:55.062466
##  7: 2026-10-11 20:32:55.062466
##  8: 2026-10-11 20:32:55.062466
##  9: 2026-10-11 20:32:55.062466
## 10: 2026-10-11 20:32:55.062466
## 11: 2026-10-11 20:32:55.062466
## 12: 2026-10-11 20:32:55.062466
## 13: 2026-10-11 20:32:55.062466
## 14: 2026-10-11 20:32:55.062466
## 15: 2026-10-11 20:32:55.055096
## 16: 2026-10-11 20:32:55.055096
## 17: 2026-10-11 20:32:55.055096
## 18: 2026-10-11 20:32:55.055096
## 19: 2026-10-11 20:32:55.055096
## 20: 2026-10-11 20:32:55.055096
## 21: 2026-10-11 20:32:55.055096
## 22: 2026-10-11 20:32:55.055096
## 23: 2026-10-11 20:32:55.055096
## 24: 2026-10-11 20:32:55.055096
## 25: 2026-10-11 20:32:55.055096
## 26: 2026-10-11 20:32:55.055096
## 27: 2026-10-11 20:32:55.055096
## 28: 2026-10-11 20:32:55.055096
##                    createdDate
##                         <char>
# keep only objects that are either runif or rnorm ("or" search)
keepCache(tmpDir, userTags = "runif|rnorm", ask = FALSE)
## Nothing to remove; keeping all
##              cacheId              tagKey                  tagValue
##               <char>              <char>                    <char>
##  1: adf21923cd1e50d0            function                     rnorm
##  2: adf21923cd1e50d0          objectName                         b
##  3: adf21923cd1e50d0            accessed 2026-10-11 20:32:55.06025
##  4: adf21923cd1e50d0             inCloud                     FALSE
##  5: adf21923cd1e50d0   elapsedTimeDigest          0.001813889 secs
##  6: adf21923cd1e50d0           preDigest     .FUN:4f604aa46882b368
##  7: adf21923cd1e50d0           preDigest     mean:c40c00762a0dac94
##  8: adf21923cd1e50d0           preDigest        n:7eef4eae85fd9229
##  9: adf21923cd1e50d0           preDigest       sd:853b1797f54b229c
## 10: adf21923cd1e50d0               class                   numeric
## 11: adf21923cd1e50d0         object.size                        80
## 12: adf21923cd1e50d0            fromDisk                     FALSE
## 13: adf21923cd1e50d0          resultHash                          
## 14: adf21923cd1e50d0 elapsedTimeFirstRun         0.0009953976 secs
## 15: e23cab430872a0ea            function                     runif
## 16: e23cab430872a0ea          objectName                         a
## 17: e23cab430872a0ea            accessed 2026-10-11 20:32:55.05275
## 18: e23cab430872a0ea             inCloud                     FALSE
## 19: e23cab430872a0ea   elapsedTimeDigest          0.001894712 secs
## 20: e23cab430872a0ea           preDigest     .FUN:881ec847b7161f3c
## 21: e23cab430872a0ea           preDigest      max:853b1797f54b229c
## 22: e23cab430872a0ea           preDigest      min:c40c00762a0dac94
## 23: e23cab430872a0ea           preDigest        n:7eef4eae85fd9229
## 24: e23cab430872a0ea               class                   numeric
## 25: e23cab430872a0ea         object.size                        80
## 26: e23cab430872a0ea            fromDisk                     FALSE
## 27: e23cab430872a0ea          resultHash                          
## 28: e23cab430872a0ea elapsedTimeFirstRun          0.001132488 secs
##              cacheId              tagKey                  tagValue
##               <char>              <char>                    <char>
##                    createdDate
##                         <char>
##  1: 2026-10-11 20:32:55.062466
##  2: 2026-10-11 20:32:55.062466
##  3: 2026-10-11 20:32:55.062466
##  4: 2026-10-11 20:32:55.062466
##  5: 2026-10-11 20:32:55.062466
##  6: 2026-10-11 20:32:55.062466
##  7: 2026-10-11 20:32:55.062466
##  8: 2026-10-11 20:32:55.062466
##  9: 2026-10-11 20:32:55.062466
## 10: 2026-10-11 20:32:55.062466
## 11: 2026-10-11 20:32:55.062466
## 12: 2026-10-11 20:32:55.062466
## 13: 2026-10-11 20:32:55.062466
## 14: 2026-10-11 20:32:55.062466
## 15: 2026-10-11 20:32:55.055096
## 16: 2026-10-11 20:32:55.055096
## 17: 2026-10-11 20:32:55.055096
## 18: 2026-10-11 20:32:55.055096
## 19: 2026-10-11 20:32:55.055096
## 20: 2026-10-11 20:32:55.055096
## 21: 2026-10-11 20:32:55.055096
## 22: 2026-10-11 20:32:55.055096
## 23: 2026-10-11 20:32:55.055096
## 24: 2026-10-11 20:32:55.055096
## 25: 2026-10-11 20:32:55.055096
## 26: 2026-10-11 20:32:55.055096
## 27: 2026-10-11 20:32:55.055096
## 28: 2026-10-11 20:32:55.055096
##                    createdDate
##                         <char>
clearCache(tmpDir, ask = FALSE)

Example 5: using caching to speed up rerunning expensive computations

ras <- terra::rast(terra::ext(0, 5, 0, 5),
  res = 1,
  vals = sample(1:5, replace = TRUE, size = 25),
  crs = "+proj=lcc +lat_1=48 +lat_2=33 +lon_0=-100 +ellps=WGS84"
)

rasCRS <- terra::crs(ras)
# Build an explicit target raster (same CRS, coarser resolution).
# Avoids the `terra::project(x, char_crs, res = N)` shorthand which
# recurses internally and forwards an unrecognized `wopt` set on
# recent terra versions, producing
# `[write] unknown option(s): xscale,yscale`.
rasTarget <- terra::rast(terra::ext(ras), crs = rasCRS, resolution = 5)

# A slow operation, like GIS operation
notCached <- suppressWarnings(
  # project raster generates warnings when run non-interactively
  terra::project(ras, rasTarget)
)

cached <- suppressWarnings(
  # project raster generates warnings when run non-interactively
  # using quote works also
  terra::project(ras, rasTarget) |> Cache(cachePath = tmpDir)
)
## Saved! Cache file: 5895373b1892f73e.rds; fn: project
# second time is much faster
reRun <- suppressWarnings(
  # project raster generates warnings when run non-interactively
  terra::project(ras, rasTarget) |> Cache(cachePath = tmpDir)
)
## Object to retrieve (fn: project, 5895373b1892f73e.rds) ...
## Loaded! Cached result from previous project call
# recovered cached version is same as non-cached version
all.equal(notCached, reRun, check.attributes = FALSE) ## TRUE
## [1] "Attributes: < Names: 2 string mismatches >"                                                    
## [2] "Attributes: < Length mismatch: comparison on first 2 components >"                             
## [3] "Attributes: < Component 1: Modes: character, list >"                                           
## [4] "Attributes: < Component 1: names for current but not for target >"                             
## [5] "Attributes: < Component 1: Attributes: < names for target but not for current > >"             
## [6] "Attributes: < Component 1: Attributes: < Length mismatch: comparison on first 0 components > >"
## [7] "Attributes: < Component 1: target is character, current is list >"                             
## [8] "Attributes: < Component 2: 'current' is not an envRefClass >"

Nested Caching

Nested caching, which is when Caching of a function occurs inside an outer function, which is itself cached. This is a critical element to working within a reproducible work flow. It is not enough during development to cache flat code chunks, as there will be many levels of “slow” functions. Ideally, at all points in a development cycle, it should be possible to get to any line of code starting from the very initial steps, running through everything up to that point, in less than a few seconds. If the workflow can be kept very fast like this, then there is a guarantee that it will work at any point.

##########################
## Nested Caching
# Make 2 functions
inner <- function(mean) {
  d <- 1
  rnorm(n = 3, mean = mean)
}
outer <- function(n) {
  inner(0.1) |> Cache(cachePath = tmpdir2)
}

# make 2 different cache paths
tmpdir1 <- file.path(tempfile(), "first")
tmpdir2 <- file.path(tempfile(), "second")

# Run the Cache ... notOlderThan propagates to all 3 Cache calls,
#   but cachePath is tmpdir1 in top level Cache and all nested
#   Cache calls, unless individually overridden ... here inner
#   uses tmpdir2 repository
outer(n = 2) |> Cache(cachePath = tmpdir1)
## Saved! Cache file: a352d42cb0291199.rds; fn: inner
## Saved! Cache file: 61564dd5e84ab6d5.rds; fn: outer
## [1] -0.07595336 -0.90167436  0.10709071
## attr(,".Cache")
## attr(,".Cache")$newCache
## [1] TRUE
## 
## attr(,"tags")
## [1] "cacheId:61564dd5e84ab6d5"
## attr(,"callInCache")
## [1] ""
showCache(tmpdir1) # 2 function calls
## Cache size:
## Total (including Rasters): 252 bytes
## Selected objects (not including Rasters): 252 bytes
##              cacheId              tagKey                  tagValue
##               <char>              <char>                    <char>
##  1: 61564dd5e84ab6d5            function                     outer
##  2: 61564dd5e84ab6d5            accessed 2026-10-11 20:32:55.27315
##  3: 61564dd5e84ab6d5             inCloud                     FALSE
##  4: 61564dd5e84ab6d5   elapsedTimeDigest          0.002167702 secs
##  5: 61564dd5e84ab6d5           preDigest     .FUN:fd3ff16451bebbef
##  6: 61564dd5e84ab6d5           preDigest        n:82dc709f2b91918a
##  7: 61564dd5e84ab6d5               class                   numeric
##  8: 61564dd5e84ab6d5         object.size                      1008
##  9: 61564dd5e84ab6d5            fromDisk                     FALSE
## 10: 61564dd5e84ab6d5          resultHash                          
## 11: 61564dd5e84ab6d5 elapsedTimeFirstRun           0.00830102 secs
##                    createdDate
##                         <char>
##  1: 2026-10-11 20:32:55.282801
##  2: 2026-10-11 20:32:55.282801
##  3: 2026-10-11 20:32:55.282801
##  4: 2026-10-11 20:32:55.282801
##  5: 2026-10-11 20:32:55.282801
##  6: 2026-10-11 20:32:55.282801
##  7: 2026-10-11 20:32:55.282801
##  8: 2026-10-11 20:32:55.282801
##  9: 2026-10-11 20:32:55.282801
## 10: 2026-10-11 20:32:55.282801
## 11: 2026-10-11 20:32:55.282801
showCache(tmpdir2) # 1 function call
## Cache size:
## Total (including Rasters): 20 bytes
## Selected objects (not including Rasters): 20 bytes
##              cacheId              tagKey                  tagValue
##               <char>              <char>                    <char>
##  1: a352d42cb0291199            function                     inner
##  2: a352d42cb0291199       outerFunction                     outer
##  3: a352d42cb0291199            accessed 2026-10-11 20:32:55.27678
##  4: a352d42cb0291199             inCloud                     FALSE
##  5: a352d42cb0291199   elapsedTimeDigest          0.001963615 secs
##  6: a352d42cb0291199           preDigest     .FUN:c411a17f70613a02
##  7: a352d42cb0291199           preDigest     mean:22413394efd9f6a3
##  8: a352d42cb0291199               class                   numeric
##  9: a352d42cb0291199         object.size                        80
## 10: a352d42cb0291199            fromDisk                     FALSE
## 11: a352d42cb0291199          resultHash                          
## 12: a352d42cb0291199 elapsedTimeFirstRun          0.001012087 secs
##                    createdDate
##                         <char>
##  1: 2026-10-11 20:32:55.279037
##  2: 2026-10-11 20:32:55.279037
##  3: 2026-10-11 20:32:55.279037
##  4: 2026-10-11 20:32:55.279037
##  5: 2026-10-11 20:32:55.279037
##  6: 2026-10-11 20:32:55.279037
##  7: 2026-10-11 20:32:55.279037
##  8: 2026-10-11 20:32:55.279037
##  9: 2026-10-11 20:32:55.279037
## 10: 2026-10-11 20:32:55.279037
## 11: 2026-10-11 20:32:55.279037
## 12: 2026-10-11 20:32:55.279037
# userTags get appended
# all items have the outer tag propagate, plus inner ones only have inner ones
clearCache(tmpdir1, ask = FALSE)
outerTag <- "outerTag"
innerTag <- "innerTag"
inner <- function(mean) {
  d <- 1
  rnorm(n = 3, mean = mean) |> Cache(notOlderThan = Sys.time() - 1e5, userTags = innerTag)
}
outer <- function(n) {
  inner(0.1) |> Cache()
}
aa <- Cache(outer, n = 2) |> Cache(cachePath = tmpdir1, userTags = outerTag)
## No cachePath supplied and getOption('reproducible.cachePath') is inside a temporary directory;
##   this will not persist across R sessions.
## No cachePath supplied and getOption('reproducible.cachePath') is inside a temporary directory;
##   this will not persist across R sessions.
## No cachePath supplied and getOption('reproducible.cachePath') is inside a temporary directory;
##   this will not persist across R sessions.
## Saved! Cache file: a481e2b85f7337f2.rds; fn: rnorm
## Saved! Cache file: 9691c7bae9ad6582.rds; fn: inner
## Saved! Cache file: 2d26a68d5154433e.rds; fn: outer
## Saved! Cache file: c384b23e661caeb7.rds; fn: Cache
showCache(tmpdir1) # rnorm function has outerTag and innerTag, inner and outer only have outerTag
## Cache size:
## Total (including Rasters): 252 bytes
## Selected objects (not including Rasters): 252 bytes
##              cacheId              tagKey                         tagValue
##               <char>              <char>                           <char>
##  1: c384b23e661caeb7            function                            Cache
##  2: c384b23e661caeb7            userTags                         outerTag
##  3: c384b23e661caeb7            accessed        2026-10-11 20:32:55.30547
##  4: c384b23e661caeb7             inCloud                            FALSE
##  5: c384b23e661caeb7   elapsedTimeDigest                 0.002666712 secs
##  6: c384b23e661caeb7           preDigest  .cacheChaining:71681d621365dfd7
##  7: c384b23e661caeb7           preDigest     .cacheExtra:c85d88fc56f4e042
##  8: c384b23e661caeb7           preDigest            .FUN:1b670f52e1b13bd1
##  9: c384b23e661caeb7           preDigest   .functionName:c85d88fc56f4e042
## 10: c384b23e661caeb7           preDigest            conn:118387d5d48f757d
## 11: c384b23e661caeb7           preDigest             drv:9ce9a83896bf68a1
## 12: c384b23e661caeb7           preDigest               n:82dc709f2b91918a
## 13: c384b23e661caeb7           preDigest cacheSaveFormat:cf2828ea967d53e7
## 14: c384b23e661caeb7           preDigest          dryRun:e9aac936a0e8f6ae
## 15: c384b23e661caeb7           preDigest             FUN:f4ab56347506d214
## 16: c384b23e661caeb7               class                          numeric
## 17: c384b23e661caeb7         object.size                             1008
## 18: c384b23e661caeb7            fromDisk                            FALSE
## 19: c384b23e661caeb7          resultHash                                 
## 20: c384b23e661caeb7 elapsedTimeFirstRun                  0.02377295 secs
##              cacheId              tagKey                         tagValue
##               <char>              <char>                           <char>
##                    createdDate
##                         <char>
##  1: 2026-10-11 20:32:55.330481
##  2: 2026-10-11 20:32:55.330481
##  3: 2026-10-11 20:32:55.330481
##  4: 2026-10-11 20:32:55.330481
##  5: 2026-10-11 20:32:55.330481
##  6: 2026-10-11 20:32:55.330481
##  7: 2026-10-11 20:32:55.330481
##  8: 2026-10-11 20:32:55.330481
##  9: 2026-10-11 20:32:55.330481
## 10: 2026-10-11 20:32:55.330481
## 11: 2026-10-11 20:32:55.330481
## 12: 2026-10-11 20:32:55.330481
## 13: 2026-10-11 20:32:55.330481
## 14: 2026-10-11 20:32:55.330481
## 15: 2026-10-11 20:32:55.330481
## 16: 2026-10-11 20:32:55.330481
## 17: 2026-10-11 20:32:55.330481
## 18: 2026-10-11 20:32:55.330481
## 19: 2026-10-11 20:32:55.330481
## 20: 2026-10-11 20:32:55.330481
##                    createdDate
##                         <char>

cacheId

Sometimes, it is not absolutely desirable to maintain the work flow intact because changes that are irrelevant to the analysis, such as changing messages sent to a user, may be changed, without a desire to rerun functions. The cacheId argument is for this. Once a piece of code is run, then the cacheId can be manually extracted (it is reported at the end of a Cache call) and manually placed in the code, passed in as, say, cacheId = "ad184ce64541972b50afd8e7b75f821b".

### cacheId
set.seed(1)
rnorm(1) |> Cache(cachePath = tmpdir1)
## Saved! Cache file: ca275879d5116967.rds; fn: rnorm
## [1] -0.6264538
## attr(,".Cache")
## attr(,".Cache")$newCache
## [1] TRUE
## 
## attr(,"tags")
## [1] "cacheId:ca275879d5116967"
## attr(,"callInCache")
## [1] ""
# manually look at output attribute which shows cacheId: 422bae4ed2f770cc
rnorm(1) |> Cache(cachePath = tmpdir1, cacheId = "422bae4ed2f770cc") # same value
## cacheId passed to override automatic digesting; using 422bae4ed2f770cc
## Saved! Cache file: 422bae4ed2f770cc.rds; fn: rnorm
## [1] 0.1836433
## attr(,".Cache")
## attr(,".Cache")$newCache
## [1] TRUE
## 
## attr(,"tags")
## [1] "cacheId:422bae4ed2f770cc"
## attr(,"callInCache")
## [1] ""
# override even with different inputs:
rnorm(2) |> Cache(cachePath = tmpdir1, cacheId = "422bae4ed2f770cc")
## cacheId passed to override automatic digesting; using 422bae4ed2f770cc
## Object to retrieve (fn: rnorm, 422bae4ed2f770cc.rds) ...
## Loaded! Cached result from previous rnorm call
## [1] 0.1836433
## attr(,".Cache")
## attr(,".Cache")$newCache
## [1] FALSE
## 
## attr(,"tags")
## [1] "cacheId:422bae4ed2f770cc"
## attr(,"callInCache")
## [1] ""

Working with the Cache manually

Since the cache is simply a DBI data table (of an SQLite database by default). In addition, there are several helpers in the reproducible package, including showCache, keepCache and clearCache that may be useful. Also, one can access cached items manually (rather than simply rerunning the same Cache function again).

# As of reproducible version 1.0, there is a new backend directly using DBI
mapHash <- unique(showCache(tmpDir, userTags = "project")$cacheId)
## Cache size:
## Total (including Rasters): 676 bytes
## Selected objects (not including Rasters): 676 bytes
map <- loadFromCache(mapHash[1], cachePath = tmpDir)
## Loaded! Cached result from previous  call
terra::plot(map)

## cleanup
unlink(dirname(tmpDir), recursive = TRUE)

Alternative database backends

By default, caching relies on a sqlite database for it’s backend. While this works in many situations, there are some important limitations of using sqlite for caching, including 1) speed; 2) concurrent transactions; 3) sharing database across machines or projects. Fortunately, Cache makes use of DBI package and thus supports several database backends, including mysql and postgresql.

See https://github.com/PredictiveEcology/SpaDES/wiki/Using-alternate-database-backends-for-Cache for further information on configuring these additional backends.

Reproducible workflow

In general, we feel that a liberal use of Cache will make a re-usable and reproducible work flow. shiny apps can be made, taking advantage of Cache. Indeed, much of the difficulty in managing data sets and saving them for future use, can be accommodated by caching.