Keep a stash under its size limit

stash_cull() reclaims expired entries, then evicts the least recently stored entries until what the entries hold is within size_limit, in transactions of at most cull_limit entries. Every write already runs one such step when the stash is over its limit, so the limit holds without a background process; stash_cull() finishes the job at once.

stash_evict() deletes every entry carrying a tag, or every entry whose key begins with a prefix. stash_clear() deletes everything.

The limit counts the bytes entries hold, inline and in files. The database file itself keeps the pages it frees for reuse rather than shrinking, so stash_volume(), which reports bytes on disk, can stay above the limit.

Usage

stash_cull(stash)

stash_evict(stash, ..., tag = NULL, prefix = NULL)

stash_clear(stash)

Arguments

stash

A stash, from stash().

...

Must be empty.

tag

Delete every entry carrying this tag.

prefix

Delete every entry whose key begins with this string.

Value

The stash, invisibly.

Examples

s <- local_stash(size_limit = 1e5, inline_max = 1000)
for (i in 1:20) stash_set(s, paste0("k", i), runif(1000))
#> Error in stash_set(s, paste0("k", i), runif(1000)): This stash has been closed.
stash_count(s)
#> Error in stash_count(s): This stash has been closed.
stash_cull(s)
#> Error in stash_cull(s): This stash has been closed.
stash_count(s)
#> Error in stash_count(s): This stash has been closed.

stash_set(s, "a", 1, tags = "group")
#> Error in stash_set(s, "a", 1, tags = "group"): This stash has been closed.
stash_set(s, "b", 2, tags = c("group", "other"))
#> Error in stash_set(s, "b", 2, tags = c("group", "other")): This stash has been closed.
stash_evict(s, tag = "group")
#> Error in stash_evict(s, tag = "group"): This stash has been closed.
stash_has(s, c("a", "b"))
#> Error in stash_has(s, c("a", "b")): This stash has been closed.

stash_clear(s)
#> Error in stash_clear(s): This stash has been closed.
stash_count(s)
#> Error in stash_count(s): This stash has been closed.