From: Timo Sirainen <tss@iki.fi>
Date: Mon, 30 Mar 2009 20:18:25 +0000 (-0400)
Subject: Write to main index file less often.
X-Git-Tag: 2.0.alpha1~1038^2~7
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=686c00553a7cea22272548d9fb8c888170965ec9;p=thirdparty%2Fdovecot%2Fcore.git

Write to main index file less often.

--HG--
branch : HEAD
---

diff --git a/src/lib-index/mail-index-private.h b/src/lib-index/mail-index-private.h
index 1a843d18c3..4af66c56ad 100644
--- a/src/lib-index/mail-index-private.h
+++ b/src/lib-index/mail-index-private.h
@@ -22,6 +22,11 @@ struct mail_index_sync_map_ctx;
    try to catch them by limiting the header size. */
 #define MAIL_INDEX_EXT_HEADER_MAX_SIZE (1024*1024*16-1)
 
+/* Write to main index file when bytes-to-be-read-from-log is between these
+   values. */
+#define MAIL_INDEX_MIN_WRITE_BYTES (1024*8)
+#define MAIL_INDEX_MAX_WRITE_BYTES (1024*128)
+
 #define MAIL_INDEX_IS_IN_MEMORY(index) \
 	((index)->dir == NULL)
 
@@ -227,6 +232,7 @@ struct mail_index {
 	unsigned int mapping:1;
 	unsigned int syncing:1;
 	unsigned int need_recreate:1;
+	unsigned int index_min_write:1;
 	unsigned int modseqs_enabled:1;
 	unsigned int initial_create:1;
 	unsigned int initial_mapped:1;
diff --git a/src/lib-index/mail-index-sync-update.c b/src/lib-index/mail-index-sync-update.c
index cae0a978ed..329b33aeb6 100644
--- a/src/lib-index/mail-index-sync-update.c
+++ b/src/lib-index/mail-index-sync-update.c
@@ -811,6 +811,15 @@ int mail_index_sync_map(struct mail_index_map **_map,
 		return 0;
 	}
 
+	mail_transaction_log_get_head(index->log, &prev_seq, &prev_offset);
+	if (prev_seq != map->hdr.log_file_seq ||
+	    prev_offset - map->hdr.log_file_tail_offset >
+	    				MAIL_INDEX_MIN_WRITE_BYTES) {
+		/* we're reading more from log than we would have preferred.
+		   remember that we probably want to rewrite index soon. */
+		index->index_min_write = TRUE;
+	}
+
 	/* view referenced the map. avoid unnecessary map cloning by
 	   unreferencing the map while view exists. */
 	map->refcount--;
diff --git a/src/lib-index/mail-index-sync.c b/src/lib-index/mail-index-sync.c
index d30c46b2cf..b5b746c104 100644
--- a/src/lib-index/mail-index-sync.c
+++ b/src/lib-index/mail-index-sync.c
@@ -731,7 +731,8 @@ static bool mail_index_sync_want_index_write(struct mail_index *index)
 
 	log_diff = index->map->hdr.log_file_tail_offset -
 		index->last_read_log_file_tail_offset;
-	if (log_diff > 1024)
+	if (log_diff > MAIL_INDEX_MAX_WRITE_BYTES ||
+	    (index->index_min_write && log_diff > MAIL_INDEX_MIN_WRITE_BYTES))
 		return TRUE;
 
 	if (index->need_recreate)
@@ -780,6 +781,7 @@ int mail_index_sync_commit(struct mail_index_sync_ctx **_ctx)
 	if (ret == 0 &&
 	    (want_rotate || mail_index_sync_want_index_write(index))) {
 		index->need_recreate = FALSE;
+		index->index_min_write = FALSE;
 		mail_index_write(index, want_rotate);
 	}
 	mail_index_sync_end(_ctx);