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-rw-r--r--modules/prefetch/prefetch.lua21
1 files changed, 21 insertions, 0 deletions
diff --git a/modules/prefetch/prefetch.lua b/modules/prefetch/prefetch.lua
new file mode 100644
index 00000000..673cf3e5
--- /dev/null
+++ b/modules/prefetch/prefetch.lua
@@ -0,0 +1,21 @@
+-- SPDX-License-Identifier: GPL-3.0-or-later
+-- Speculative prefetching for repetitive and soon-expiring records to reduce latency.
+-- @module prefetch
+local prefetch = {}
+
+
+prefetch.layer = {
+ -- Prefetch all expiring (sub-)queries immediately after the request finishes.
+ -- Doing that immediately is simplest and avoids creating (new) large bursts of activity.
+ finish = function (_, req)
+ local qrys = req.rplan.resolved
+ for i = 0, (tonumber(qrys.len) - 1) do -- size_t doesn't work for some reason
+ local qry = qrys.at[i]
+ if qry.flags.EXPIRING == true then
+ resolve(kres.dname2str(qry.sname), qry.stype, qry.sclass, {'NO_CACHE'})
+ end
+ end
+ end
+}
+
+return prefetch