From 7642f50ebbbf1baa475dc4342aba2fdb34930e55 Mon Sep 17 00:00:00 2001
From: Jason Volk <jason@zemos.net>
Date: Sun, 6 Sep 2020 02:58:49 -0700
Subject: [PATCH] ircd::m::events: Add readahead; add conf item.

---
 matrix/events.cc | 18 ++++++++++++++++--
 1 file changed, 16 insertions(+), 2 deletions(-)

diff --git a/matrix/events.cc b/matrix/events.cc
index def47cbb6..75029fd49 100644
--- a/matrix/events.cc
+++ b/matrix/events.cc
@@ -347,6 +347,18 @@ ircd::m::events::for_each(const range &range,
 // events::state
 //
 
+namespace ircd::m::events::content
+{
+	extern conf::item<size_t> readahead;
+}
+
+decltype(ircd::m::events::content::readahead)
+ircd::m::events::content::readahead
+{
+	{ "name",     "ircd.m.events.content.readahead" },
+	{ "default",  long(4_MiB)                       },
+};
+
 bool
 ircd::m::events::content::for_each(const closure &closure)
 {
@@ -360,13 +372,15 @@ ircd::m::events::content::for_each(const closure &closure)
 		dbs::event_column.at(content_idx)
 	};
 
-	static const db::gopts gopts
+	db::gopts gopts
 	{
 		db::get::NO_CACHE,
 		db::get::NO_CHECKSUM
 	};
 
-	for(auto it(column.begin(gopts)); bool(it); ++it)
+	gopts.readahead = size_t(readahead);
+	auto it(column.begin(gopts));
+	for(; it; ++it)
 	{
 		const auto &event_idx
 		{