From: Marco Bettini <marco.bettini@open-xchange.com>
Date: Tue, 6 Dec 2022 11:31:21 +0000 (+0000)
Subject: lib-index: Shorten mail_cache_unaccessed_field_drop effective value to 1/4 while... 
X-Git-Tag: 2.4.0~3269
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=19890c0d30d1c4270831e1ed42dfc6569bd086b9;p=thirdparty%2Fdovecot%2Fcore.git

lib-index: Shorten mail_cache_unaccessed_field_drop effective value to 1/4 while cache header count is saturated

This is done to help the cache to converge quicker to the intended state.
---

diff --git a/src/lib-index/mail-cache-purge.c b/src/lib-index/mail-cache-purge.c
index 477f80d2a3..789689f854 100644
--- a/src/lib-index/mail-cache-purge.c
+++ b/src/lib-index/mail-cache-purge.c
@@ -675,10 +675,16 @@ void mail_cache_purge_drop_init(struct mail_cache *cache,
 	if (hdr->day_stamp != 0) {
 		const struct mail_index_cache_optimization_settings *opt =
 			&cache->index->optimization_set.cache;
-		ctx_r->max_yes_downgrade_time = hdr->day_stamp -
-			opt->unaccessed_field_drop_secs;
-		ctx_r->max_temp_drop_time = hdr->day_stamp -
-			2 * opt->unaccessed_field_drop_secs;
+		long threshold = opt->unaccessed_field_drop_secs;
+
+		/* While cache max headers count is saturated, shrink the actual
+		   value of this parameter to 1/4, so that the cache can return
+		   quicker to the intended state. */
+		if (mail_cache_headers_check_capped(cache))
+			threshold /= 4;
+
+		ctx_r->max_yes_downgrade_time = hdr->day_stamp - threshold;
+		ctx_r->max_temp_drop_time     = hdr->day_stamp - 2 * threshold;
 	}
 }
 
diff --git a/src/lib-index/test-mail-cache-purge.c b/src/lib-index/test-mail-cache-purge.c
index 790226eda6..54086af0dd 100644
--- a/src/lib-index/test-mail-cache-purge.c
+++ b/src/lib-index/test-mail-cache-purge.c
@@ -1042,6 +1042,42 @@ static void test_mail_cache_update_need_purge_deleted_records2(void)
 	test_end();
 }
 
+static void test_mail_cache_purge_deadlines(void)
+{
+	static const uint32_t BASE_TIME = 1000;
+	static const uint32_t DROP_SECS =  100;
+
+	struct mail_cache cache;
+	struct mail_index index;
+	struct mail_index_header hdr;
+	struct mail_cache_purge_drop_ctx ctx;
+
+	i_zero(&cache);
+	i_zero(&index);
+	i_zero(&hdr);
+	i_zero(&ctx);
+
+	hdr.day_stamp = BASE_TIME;
+	index.optimization_set.cache.unaccessed_field_drop_secs = DROP_SECS;
+	index.optimization_set.cache.max_headers_count = 1;
+	cache.index = &index;
+
+	test_begin("mail cache purge deadlines");
+
+	mail_cache_purge_drop_init(&cache, &hdr, &ctx);
+	test_assert_cmp(cache.headers_capped, ==, FALSE);
+	test_assert_cmp(ctx.max_yes_downgrade_time, ==, BASE_TIME - DROP_SECS);
+	test_assert_cmp(ctx.max_temp_drop_time, ==, BASE_TIME - DROP_SECS - DROP_SECS);
+
+	cache.headers_capped = TRUE;
+	mail_cache_purge_drop_init(&cache, &hdr, &ctx);
+	test_assert_cmp(cache.headers_capped, ==, TRUE);
+	test_assert_cmp(ctx.max_yes_downgrade_time, ==, BASE_TIME - DROP_SECS/4);
+	test_assert_cmp(ctx.max_temp_drop_time, ==, BASE_TIME - DROP_SECS/4 - DROP_SECS/4);
+
+	test_end();
+}
+
 int main(void)
 {
 	static void (*const test_functions[])(void) = {
@@ -1070,6 +1106,7 @@ int main(void)
 		test_mail_cache_update_need_purge_continued_records2,
 		test_mail_cache_update_need_purge_deleted_records,
 		test_mail_cache_update_need_purge_deleted_records2,
+		test_mail_cache_purge_deadlines,
 		NULL
 	};
 	return test_run(test_functions);