# HG changeset patch
# User Timo Sirainen <tss@iki.fi>
# Date 1194291447 -7200
# Node ID 76c0e3a4df7a758c99b97cb936ea121d8d428a8f
# Parent  c7742d109a672bb5ec252e726323291ceada2133
If we need to do more than 4 reads to get to the cached fields header,
compress the cache file.

diff -r c7742d109a67 -r 76c0e3a4df7a src/lib-index/mail-cache-fields.c
--- a/src/lib-index/mail-cache-fields.c	Mon Nov 05 21:15:28 2007 +0200
+++ b/src/lib-index/mail-cache-fields.c	Mon Nov 05 21:37:27 2007 +0200
@@ -173,6 +173,7 @@
 	const unsigned int size = sizeof(*field_hdr) + CACHE_HDR_PREFETCH;
 	uint32_t offset, next_offset;
 	uoff_t invalid_start = 0, invalid_end = 0;
+	unsigned int next_count = 0;
 
 	if (MAIL_CACHE_IS_UNUSABLE(cache)) {
 		*offset_r = 0;
@@ -214,8 +215,12 @@
 		field_hdr = CONST_PTR_OFFSET(cache->data, offset);
 		next_offset =
 			mail_index_offset_to_uint32(field_hdr->next_offset);
+		next_count++;
 	}
 
+	if (next_count > MAIL_CACHE_HEADER_FIELD_CONTINUE_COUNT)
+		cache->need_compress_file_seq = cache->hdr->file_seq;
+
 	*offset_r = offset;
 	return 0;
 }
diff -r c7742d109a67 -r 76c0e3a4df7a src/lib-index/mail-cache-private.h
--- a/src/lib-index/mail-cache-private.h	Mon Nov 05 21:15:28 2007 +0200
+++ b/src/lib-index/mail-cache-private.h	Mon Nov 05 21:37:27 2007 +0200
@@ -23,6 +23,10 @@
    200% means that there's 2 continued rows per record. */
 #define MAIL_CACHE_COMPRESS_CONTINUED_PERCENTAGE 200
 
+/* Compress the file when we need to follow more than n next_offsets to find
+   the latest cache header. */
+#define MAIL_CACHE_HEADER_FIELD_CONTINUE_COUNT 4
+
 /* Initial size for the file */
 #define MAIL_CACHE_INITIAL_SIZE (sizeof(struct mail_cache_header) + 10240)