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Configure experimental HTTP VFS behavior (optional)

Source: R/httpvfs_config.R
sqliteHttpConfig.Rd

lifecycle::badge("experimental")

Set conservative, process-wide options for the experimental HTTP/HTTPS VFS. These values are read on first open of a remote database in the current process.

Usage

sqliteHttpConfig(
  cache_size_mb = NULL,
  prefetch_pages = NULL,
  fallback_full_download = NULL
)

Arguments

cache_size_mb

Integer megabytes for in-memory page cache. NULL leaves unchanged.

prefetch_pages

Integer pages to prefetch ahead. NULL leaves unchanged.

fallback_full_download

Logical; if TRUE, allow full-download fallback when Range is not available. NULL leaves unchanged.

Value

A named list of previous values (in R types).

Details

Options are stored in environment variables so they also affect C-level code:

  • RSQLITE_HTTP_CACHE_MB: In-memory page cache size in megabytes (default 4).

  • RSQLITE_HTTP_PREFETCH_PAGES: Prefetch this many pages ahead (default 0).

  • RSQLITE_HTTP_FALLBACK_FULLDL: If TRUE (default), fall back to full download when the server does not support HTTP Range; if FALSE, open will fail.

Examples

old <- sqliteHttpConfig(cache_size_mb = 8, prefetch_pages = 1, fallback_full_download = TRUE)
on.exit(do.call(sqliteHttpConfig, old), add = TRUE)
# ... connect with sqliteRemote() ...