Introduction to Cache
Eliot J. B. McIntire
May 16 2026
Source:vignettes/Intro-to-Cache.Rmd
Intro-to-Cache.RmdReproducible 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.
##
## 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
## 0.029 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
## 0.514 0.123 0.635
# 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
## 0.178 0.001 0.180## [1] "Attributes: < Component \".Cache\": Component \"newCache\": 1 element mismatch >"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## Object to retrieve (fn: rnorm, aa549dd751b2f26d.rds) ...## Loaded! Cached result from previous rnorm call## No cachePath supplied and getOption('reproducible.cachePath') is inside a temporary directory;
## this will not persist across R sessions.## Saved! Cache file: aa549dd751b2f26d.rds; fn: rnorm## Saved! Cache file: 3c7f17ad95d2c47c.rds; fn: Cache## 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: c57243764d47af28.rds; fn: Cache## 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: rnormExample 1: Basic cache use with tags
## Saved! Cache file: adf21923cd1e50d0.rds; fn: rnorm## Saved! Cache file: e23cab430872a0ea.rds; fn: runif## 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 2026-05-16 16:18:13.50240
## 4: adf21923cd1e50d0 inCloud FALSE
## 5: adf21923cd1e50d0 elapsedTimeDigest 0.001718521 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 0.001065493 secs
## 15: e23cab430872a0ea function runif
## 16: e23cab430872a0ea objectName b
## 17: e23cab430872a0ea accessed 2026-05-16 16:18:13.50859
## 18: e23cab430872a0ea inCloud FALSE
## 19: e23cab430872a0ea elapsedTimeDigest 0.001430273 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 0.0009086132 secs
## cacheId tagKey tagValue
## <char> <char> <char>
## createdDate
## <char>
## 1: 2026-05-16 16:18:13.504512
## 2: 2026-05-16 16:18:13.504512
## 3: 2026-05-16 16:18:13.504512
## 4: 2026-05-16 16:18:13.504512
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## 7: 2026-05-16 16:18:13.504512
## 8: 2026-05-16 16:18:13.504512
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## 14: 2026-05-16 16:18:13.504512
## 15: 2026-05-16 16:18:13.510436
## 16: 2026-05-16 16:18:13.510436
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## 27: 2026-05-16 16:18:13.510436
## 28: 2026-05-16 16:18:13.510436
## createdDate
## <char>## 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 2026-05-16 16:18:13.50240
## 4: adf21923cd1e50d0 inCloud FALSE
## 5: adf21923cd1e50d0 elapsedTimeDigest 0.001718521 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 0.001065493 secs
## createdDate
## <char>
## 1: 2026-05-16 16:18:13.504512
## 2: 2026-05-16 16:18:13.504512
## 3: 2026-05-16 16:18:13.504512
## 4: 2026-05-16 16:18:13.504512
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## 12: 2026-05-16 16:18:13.504512
## 13: 2026-05-16 16:18:13.504512
## 14: 2026-05-16 16:18:13.504512## 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 2026-05-16 16:18:13.50859
## 4: e23cab430872a0ea inCloud FALSE
## 5: e23cab430872a0ea elapsedTimeDigest 0.001430273 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 0.0009086132 secs
## createdDate
## <char>
## 1: 2026-05-16 16:18:13.510436
## 2: 2026-05-16 16:18:13.510436
## 3: 2026-05-16 16:18:13.510436
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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: 3c7f17ad95d2c47c function Cache
## 2: 3c7f17ad95d2c47c accessed 2026-05-16 16:18:13.39765
## 3: 3c7f17ad95d2c47c inCloud FALSE
## 4: 3c7f17ad95d2c47c elapsedTimeDigest 0.002593994 secs
## 5: 3c7f17ad95d2c47c preDigest .cacheChaining:71681d621365dfd7
## 6: 3c7f17ad95d2c47c preDigest .cacheExtra:c85d88fc56f4e042
## 7: 3c7f17ad95d2c47c preDigest .FUN:a844fd4a43c312e6
## 8: 3c7f17ad95d2c47c preDigest .functionName:c85d88fc56f4e042
## 9: 3c7f17ad95d2c47c preDigest conn:118387d5d48f757d
## 10: 3c7f17ad95d2c47c preDigest drv:9ce9a83896bf68a1
## 11: 3c7f17ad95d2c47c preDigest cacheSaveFormat:cf2828ea967d53e7
## 12: 3c7f17ad95d2c47c preDigest dryRun:e9aac936a0e8f6ae
## 13: 3c7f17ad95d2c47c preDigest FUN:265d86c3bd130de5
## 14: 3c7f17ad95d2c47c class call
## 15: 3c7f17ad95d2c47c object.size 1320
## 16: 3c7f17ad95d2c47c fromDisk FALSE
## 17: 3c7f17ad95d2c47c resultHash
## 18: 3c7f17ad95d2c47c elapsedTimeFirstRun 0.008142471 secs
## 19: aa549dd751b2f26d function rnorm
## 20: aa549dd751b2f26d accessed 2026-05-16 16:18:13.38438
## 21: aa549dd751b2f26d inCloud FALSE
## 22: aa549dd751b2f26d elapsedTimeDigest 0.001542091 secs
## 23: aa549dd751b2f26d preDigest .FUN:4f604aa46882b368
## 24: aa549dd751b2f26d preDigest mean:15620f138033a66c
## 25: aa549dd751b2f26d preDigest n:c5775c3b366fb719
## 26: aa549dd751b2f26d preDigest sd:853b1797f54b229c
## 27: aa549dd751b2f26d class numeric
## 28: aa549dd751b2f26d object.size 176
## 29: aa549dd751b2f26d fromDisk FALSE
## 30: aa549dd751b2f26d resultHash
## 31: aa549dd751b2f26d elapsedTimeFirstRun 0.001164198 secs
## 32: aa549dd751b2f26d accessed 2026-05-16 16:18:13.39302
## 33: aa549dd751b2f26d accessed 2026-05-16 16:18:13.42483
## 34: adf21923cd1e50d0 function rnorm
## 35: adf21923cd1e50d0 objectName a
## 36: adf21923cd1e50d0 accessed 2026-05-16 16:18:13.50240
## 37: adf21923cd1e50d0 inCloud FALSE
## 38: adf21923cd1e50d0 elapsedTimeDigest 0.001718521 secs
## 39: adf21923cd1e50d0 preDigest .FUN:4f604aa46882b368
## 40: adf21923cd1e50d0 preDigest mean:c40c00762a0dac94
## 41: adf21923cd1e50d0 preDigest n:7eef4eae85fd9229
## 42: adf21923cd1e50d0 preDigest sd:853b1797f54b229c
## 43: adf21923cd1e50d0 class numeric
## 44: adf21923cd1e50d0 object.size 80
## 45: adf21923cd1e50d0 fromDisk FALSE
## 46: adf21923cd1e50d0 resultHash
## 47: adf21923cd1e50d0 elapsedTimeFirstRun 0.001065493 secs
## 48: c57243764d47af28 function Cache
## 49: c57243764d47af28 accessed 2026-05-16 16:18:13.41141
## 50: c57243764d47af28 inCloud FALSE
## 51: c57243764d47af28 elapsedTimeDigest 0.002382994 secs
## 52: c57243764d47af28 preDigest .cacheChaining:71681d621365dfd7
## 53: c57243764d47af28 preDigest .cacheExtra:c85d88fc56f4e042
## 54: c57243764d47af28 preDigest .FUN:a844fd4a43c312e6
## 55: c57243764d47af28 preDigest .functionName:c85d88fc56f4e042
## 56: c57243764d47af28 preDigest conn:118387d5d48f757d
## 57: c57243764d47af28 preDigest drv:9ce9a83896bf68a1
## 58: c57243764d47af28 preDigest cacheSaveFormat:cf2828ea967d53e7
## 59: c57243764d47af28 preDigest dryRun:e9aac936a0e8f6ae
## 60: c57243764d47af28 preDigest FUN:f2b5e0e1d6ee2618
## 61: c57243764d47af28 class numeric
## 62: c57243764d47af28 object.size 176
## 63: c57243764d47af28 fromDisk FALSE
## 64: c57243764d47af28 resultHash
## 65: c57243764d47af28 elapsedTimeFirstRun 0.006818295 secs
## 66: d78b46a2a76d6d80 function rnorm
## 67: d78b46a2a76d6d80 accessed 2026-05-16 16:18:13.42818
## 68: d78b46a2a76d6d80 inCloud FALSE
## 69: d78b46a2a76d6d80 elapsedTimeDigest 0.001409531 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 0.0008904934 secs
## cacheId tagKey tagValue
## <char> <char> <char>
## createdDate
## <char>
## 1: 2026-05-16 16:18:13.406744
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## createdDate
## <char>
clearCache(tmpDir, ask = FALSE)Example 2: using the “accessed” tag
## Saved! Cache file: adf21923cd1e50d0.rds; fn: rnorm## 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,createdDateExample 3: using keepCache
keepCache does the same as previous example, but more
simply.
## Saved! Cache file: adf21923cd1e50d0.rds; fn: rnorm## 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: 11a6d7fbf3456f77.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: 11a6d7fbf3456f77 function Cache
## 2: 11a6d7fbf3456f77 objectName b
## 3: 11a6d7fbf3456f77 accessed 2026-05-16 16:18:14.84107
## 4: 11a6d7fbf3456f77 inCloud FALSE
## 5: 11a6d7fbf3456f77 elapsedTimeDigest 0.004512787 secs
## 6: 11a6d7fbf3456f77 preDigest .cacheChaining:71681d621365dfd7
## 7: 11a6d7fbf3456f77 preDigest .cacheExtra:c85d88fc56f4e042
## 8: 11a6d7fbf3456f77 preDigest .FUN:a844fd4a43c312e6
## 9: 11a6d7fbf3456f77 preDigest .functionName:c85d88fc56f4e042
## 10: 11a6d7fbf3456f77 preDigest conn:118387d5d48f757d
## 11: 11a6d7fbf3456f77 preDigest drv:9ce9a83896bf68a1
## 12: 11a6d7fbf3456f77 preDigest cacheSaveFormat:cf2828ea967d53e7
## 13: 11a6d7fbf3456f77 preDigest dryRun:e9aac936a0e8f6ae
## 14: 11a6d7fbf3456f77 preDigest FUN:0ea2b04926b969cd
## 15: 11a6d7fbf3456f77 class numeric
## 16: 11a6d7fbf3456f77 object.size 1008
## 17: 11a6d7fbf3456f77 fromDisk FALSE
## 18: 11a6d7fbf3456f77 resultHash
## 19: 11a6d7fbf3456f77 elapsedTimeFirstRun 0.01387906 secs
## 20: adf21923cd1e50d0 function rnorm
## 21: adf21923cd1e50d0 objectName a
## 22: adf21923cd1e50d0 accessed 2026-05-16 16:18:14.82538
## 23: adf21923cd1e50d0 inCloud FALSE
## 24: adf21923cd1e50d0 elapsedTimeDigest 0.005806684 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 0.002897501 secs
## cacheId tagKey tagValue
## <char> <char> <char>
## createdDate
## <char>
## 1: 2026-05-16 16:18:14.856762
## 2: 2026-05-16 16:18:14.856762
## 3: 2026-05-16 16:18:14.856762
## 4: 2026-05-16 16:18:14.856762
## 5: 2026-05-16 16:18:14.856762
## 6: 2026-05-16 16:18:14.856762
## 7: 2026-05-16 16:18:14.856762
## 8: 2026-05-16 16:18:14.856762
## 9: 2026-05-16 16:18:14.856762
## 10: 2026-05-16 16:18:14.856762
## 11: 2026-05-16 16:18:14.856762
## 12: 2026-05-16 16:18:14.856762
## 13: 2026-05-16 16:18:14.856762
## 14: 2026-05-16 16:18:14.856762
## 15: 2026-05-16 16:18:14.856762
## 16: 2026-05-16 16:18:14.856762
## 17: 2026-05-16 16:18:14.856762
## 18: 2026-05-16 16:18:14.856762
## 19: 2026-05-16 16:18:14.856762
## 20: 2026-05-16 16:18:14.830556
## 21: 2026-05-16 16:18:14.830556
## 22: 2026-05-16 16:18:14.830556
## 23: 2026-05-16 16:18:14.830556
## 24: 2026-05-16 16:18:14.830556
## 25: 2026-05-16 16:18:14.830556
## 26: 2026-05-16 16:18:14.830556
## 27: 2026-05-16 16:18:14.830556
## 28: 2026-05-16 16:18:14.830556
## 29: 2026-05-16 16:18:14.830556
## 30: 2026-05-16 16:18:14.830556
## 31: 2026-05-16 16:18:14.830556
## 32: 2026-05-16 16:18:14.830556
## 33: 2026-05-16 16:18:14.830556
## 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 2026-05-16 16:18:14.82538
## 4: adf21923cd1e50d0 inCloud FALSE
## 5: adf21923cd1e50d0 elapsedTimeDigest 0.005806684 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 0.002897501 secs
## createdDate
## <char>
## 1: 2026-05-16 16:18:14.830556
## 2: 2026-05-16 16:18:14.830556
## 3: 2026-05-16 16:18:14.830556
## 4: 2026-05-16 16:18:14.830556
## 5: 2026-05-16 16:18:14.830556
## 6: 2026-05-16 16:18:14.830556
## 7: 2026-05-16 16:18:14.830556
## 8: 2026-05-16 16:18:14.830556
## 9: 2026-05-16 16:18:14.830556
## 10: 2026-05-16 16:18:14.830556
## 11: 2026-05-16 16:18:14.830556
## 12: 2026-05-16 16:18:14.830556
## 13: 2026-05-16 16:18:14.830556
## 14: 2026-05-16 16:18:14.830556
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 2026-05-16 16:18:14.82538
## 4: adf21923cd1e50d0 inCloud FALSE
## 5: adf21923cd1e50d0 elapsedTimeDigest 0.005806684 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 0.002897501 secs
## createdDate
## <char>
## 1: 2026-05-16 16:18:14.830556
## 2: 2026-05-16 16:18:14.830556
## 3: 2026-05-16 16:18:14.830556
## 4: 2026-05-16 16:18:14.830556
## 5: 2026-05-16 16:18:14.830556
## 6: 2026-05-16 16:18:14.830556
## 7: 2026-05-16 16:18:14.830556
## 8: 2026-05-16 16:18:14.830556
## 9: 2026-05-16 16:18:14.830556
## 10: 2026-05-16 16:18:14.830556
## 11: 2026-05-16 16:18:14.830556
## 12: 2026-05-16 16:18:14.830556
## 13: 2026-05-16 16:18:14.830556
## 14: 2026-05-16 16:18:14.830556
# 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 2026-05-16 16:18:15.96587
## 4: 438a3028a4570cf9 inCloud FALSE
## 5: 438a3028a4570cf9 elapsedTimeDigest 0.002588987 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 0.00173974 secs
## createdDate
## <char>
## 1: 2026-05-16 16:18:15.96915
## 2: 2026-05-16 16:18:15.96915
## 3: 2026-05-16 16:18:15.96915
## 4: 2026-05-16 16:18:15.96915
## 5: 2026-05-16 16:18:15.96915
## 6: 2026-05-16 16:18:15.96915
## 7: 2026-05-16 16:18:15.96915
## 8: 2026-05-16 16:18:15.96915
## 9: 2026-05-16 16:18:15.96915
## 10: 2026-05-16 16:18:15.96915
## 11: 2026-05-16 16:18:15.96915
## 12: 2026-05-16 16:18:15.96915
## 13: 2026-05-16 16:18:15.96915
## 14: 2026-05-16 16:18:15.96915
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## 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 2026-05-16 16:18:16.09949
## 4: adf21923cd1e50d0 inCloud FALSE
## 5: adf21923cd1e50d0 elapsedTimeDigest 0.00252533 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 0.001748085 secs
## 15: e23cab430872a0ea function runif
## 16: e23cab430872a0ea objectName a
## 17: e23cab430872a0ea accessed 2026-05-16 16:18:16.08587
## 18: e23cab430872a0ea inCloud FALSE
## 19: e23cab430872a0ea elapsedTimeDigest 0.005649805 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 0.002851248 secs
## cacheId tagKey tagValue
## <char> <char> <char>
## createdDate
## <char>
## 1: 2026-05-16 16:18:16.10304
## 2: 2026-05-16 16:18:16.10304
## 3: 2026-05-16 16:18:16.10304
## 4: 2026-05-16 16:18:16.10304
## 5: 2026-05-16 16:18:16.10304
## 6: 2026-05-16 16:18:16.10304
## 7: 2026-05-16 16:18:16.10304
## 8: 2026-05-16 16:18:16.10304
## 9: 2026-05-16 16:18:16.10304
## 10: 2026-05-16 16:18:16.10304
## 11: 2026-05-16 16:18:16.10304
## 12: 2026-05-16 16:18:16.10304
## 13: 2026-05-16 16:18:16.10304
## 14: 2026-05-16 16:18:16.10304
## 15: 2026-05-16 16:18:16.090897
## 16: 2026-05-16 16:18:16.090897
## 17: 2026-05-16 16:18:16.090897
## 18: 2026-05-16 16:18:16.090897
## 19: 2026-05-16 16:18:16.090897
## 20: 2026-05-16 16:18:16.090897
## 21: 2026-05-16 16:18:16.090897
## 22: 2026-05-16 16:18:16.090897
## 23: 2026-05-16 16:18:16.090897
## 24: 2026-05-16 16:18:16.090897
## 25: 2026-05-16 16:18:16.090897
## 26: 2026-05-16 16:18:16.090897
## 27: 2026-05-16 16:18:16.090897
## 28: 2026-05-16 16:18:16.090897
## 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 2026-05-16 16:18:16.09949
## 4: adf21923cd1e50d0 inCloud FALSE
## 5: adf21923cd1e50d0 elapsedTimeDigest 0.00252533 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 0.001748085 secs
## 15: e23cab430872a0ea function runif
## 16: e23cab430872a0ea objectName a
## 17: e23cab430872a0ea accessed 2026-05-16 16:18:16.08587
## 18: e23cab430872a0ea inCloud FALSE
## 19: e23cab430872a0ea elapsedTimeDigest 0.005649805 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 0.002851248 secs
## cacheId tagKey tagValue
## <char> <char> <char>
## createdDate
## <char>
## 1: 2026-05-16 16:18:16.10304
## 2: 2026-05-16 16:18:16.10304
## 3: 2026-05-16 16:18:16.10304
## 4: 2026-05-16 16:18:16.10304
## 5: 2026-05-16 16:18:16.10304
## 6: 2026-05-16 16:18:16.10304
## 7: 2026-05-16 16:18:16.10304
## 8: 2026-05-16 16:18:16.10304
## 9: 2026-05-16 16:18:16.10304
## 10: 2026-05-16 16:18:16.10304
## 11: 2026-05-16 16:18:16.10304
## 12: 2026-05-16 16:18:16.10304
## 13: 2026-05-16 16:18:16.10304
## 14: 2026-05-16 16:18:16.10304
## 15: 2026-05-16 16:18:16.090897
## 16: 2026-05-16 16:18:16.090897
## 17: 2026-05-16 16:18:16.090897
## 18: 2026-05-16 16:18:16.090897
## 19: 2026-05-16 16:18:16.090897
## 20: 2026-05-16 16:18:16.090897
## 21: 2026-05-16 16:18:16.090897
## 22: 2026-05-16 16:18:16.090897
## 23: 2026-05-16 16:18:16.090897
## 24: 2026-05-16 16:18:16.090897
## 25: 2026-05-16 16:18:16.090897
## 26: 2026-05-16 16:18:16.090897
## 27: 2026-05-16 16:18:16.090897
## 28: 2026-05-16 16:18:16.090897
## 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 2026-05-16 16:18:16.09949
## 4: adf21923cd1e50d0 inCloud FALSE
## 5: adf21923cd1e50d0 elapsedTimeDigest 0.00252533 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 0.001748085 secs
## 15: e23cab430872a0ea function runif
## 16: e23cab430872a0ea objectName a
## 17: e23cab430872a0ea accessed 2026-05-16 16:18:16.08587
## 18: e23cab430872a0ea inCloud FALSE
## 19: e23cab430872a0ea elapsedTimeDigest 0.005649805 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 0.002851248 secs
## cacheId tagKey tagValue
## <char> <char> <char>
## createdDate
## <char>
## 1: 2026-05-16 16:18:16.10304
## 2: 2026-05-16 16:18:16.10304
## 3: 2026-05-16 16:18:16.10304
## 4: 2026-05-16 16:18:16.10304
## 5: 2026-05-16 16:18:16.10304
## 6: 2026-05-16 16:18:16.10304
## 7: 2026-05-16 16:18:16.10304
## 8: 2026-05-16 16:18:16.10304
## 9: 2026-05-16 16:18:16.10304
## 10: 2026-05-16 16:18:16.10304
## 11: 2026-05-16 16:18:16.10304
## 12: 2026-05-16 16:18:16.10304
## 13: 2026-05-16 16:18:16.10304
## 14: 2026-05-16 16:18:16.10304
## 15: 2026-05-16 16:18:16.090897
## 16: 2026-05-16 16:18:16.090897
## 17: 2026-05-16 16:18:16.090897
## 18: 2026-05-16 16:18:16.090897
## 19: 2026-05-16 16:18:16.090897
## 20: 2026-05-16 16:18:16.090897
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## 28: 2026-05-16 16:18:16.090897
## 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: bc663c9b226de9f2.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, bc663c9b226de9f2.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] -0.6854327 -0.9567369 -0.6955414
## 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 2026-05-16 16:18:16.54489
## 3: 61564dd5e84ab6d5 inCloud FALSE
## 4: 61564dd5e84ab6d5 elapsedTimeDigest 0.006633997 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 0.02890611 secs
## createdDate
## <char>
## 1: 2026-05-16 16:18:16.575719
## 2: 2026-05-16 16:18:16.575719
## 3: 2026-05-16 16:18:16.575719
## 4: 2026-05-16 16:18:16.575719
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## 11: 2026-05-16 16:18:16.575719
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 2026-05-16 16:18:16.56292
## 4: a352d42cb0291199 inCloud FALSE
## 5: a352d42cb0291199 elapsedTimeDigest 0.00629282 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 0.003668308 secs
## createdDate
## <char>
## 1: 2026-05-16 16:18:16.568987
## 2: 2026-05-16 16:18:16.568987
## 3: 2026-05-16 16:18:16.568987
## 4: 2026-05-16 16:18:16.568987
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## 12: 2026-05-16 16:18:16.568987
# 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: ad4fe405053618ab.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: ad4fe405053618ab function Cache
## 2: ad4fe405053618ab userTags outerTag
## 3: ad4fe405053618ab accessed 2026-05-16 16:18:16.64138
## 4: ad4fe405053618ab inCloud FALSE
## 5: ad4fe405053618ab elapsedTimeDigest 0.00693655 secs
## 6: ad4fe405053618ab preDigest .cacheChaining:71681d621365dfd7
## 7: ad4fe405053618ab preDigest .cacheExtra:c85d88fc56f4e042
## 8: ad4fe405053618ab preDigest .FUN:a844fd4a43c312e6
## 9: ad4fe405053618ab preDigest .functionName:c85d88fc56f4e042
## 10: ad4fe405053618ab preDigest conn:118387d5d48f757d
## 11: ad4fe405053618ab preDigest drv:9ce9a83896bf68a1
## 12: ad4fe405053618ab preDigest n:82dc709f2b91918a
## 13: ad4fe405053618ab preDigest cacheSaveFormat:cf2828ea967d53e7
## 14: ad4fe405053618ab preDigest dryRun:e9aac936a0e8f6ae
## 15: ad4fe405053618ab preDigest FUN:f4ab56347506d214
## 16: ad4fe405053618ab class numeric
## 17: ad4fe405053618ab object.size 1008
## 18: ad4fe405053618ab fromDisk FALSE
## 19: ad4fe405053618ab resultHash
## 20: ad4fe405053618ab elapsedTimeFirstRun 0.03758407 secs
## cacheId tagKey tagValue
## <char> <char> <char>
## createdDate
## <char>
## 1: 2026-05-16 16:18:16.68034
## 2: 2026-05-16 16:18:16.68034
## 3: 2026-05-16 16:18:16.68034
## 4: 2026-05-16 16:18:16.68034
## 5: 2026-05-16 16:18:16.68034
## 6: 2026-05-16 16:18:16.68034
## 7: 2026-05-16 16:18:16.68034
## 8: 2026-05-16 16:18:16.68034
## 9: 2026-05-16 16:18:16.68034
## 10: 2026-05-16 16:18:16.68034
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## 20: 2026-05-16 16:18:16.68034
## 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".
## 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)
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.