From afe1de5d98f2f4eb3d1fa495f090a1f99551d61a Mon Sep 17 00:00:00 2001
From: Willy Tarreau <w@1wt.eu>
Date: Wed, 4 Apr 2018 11:56:43 +0200
Subject: [PATCH] BUG/MINOR: cache: fix "show cache" output
The "show cache" command used to dump the header for each entry into into
the handler loop, making it repeated every ~16kB of output data. Additionally
chunk_appendf() was used instead of chunk_printf(), causing the output to
repeat already emitted lines, and the output size to grow in O(n^2). It used
to take several minutes to report tens of millions of objects from a small
cache containing only a few thousands. There was no more impact though.
This fix must be backported to 1.8.
---
src/cache.c | 15 +++++++++------
1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/src/cache.c b/src/cache.c
index 39d8196ac..419324f97 100644
--- a/src/cache.c
+++ b/src/cache.c
@@ -963,9 +963,6 @@ static int cli_io_handler_show_cache(struct appctx *appctx)
struct cache* cache = appctx->ctx.cli.p0;
struct stream_interface *si = appctx->owner;
- chunk_reset(&trash);
-
-
if (cache == NULL) {
cache = LIST_ELEM((caches).n, typeof(struct cache *), list);
}
@@ -975,9 +972,14 @@ static int cli_io_handler_show_cache(struct appctx *appctx)
unsigned int next_key;
struct cache_entry *entry;
- chunk_appendf(&trash, "%p: %s (shctx:%p, available blocks:%d)\n", cache, cache->id, shctx_ptr(cache), shctx_ptr(cache)->nbav);
-
next_key = appctx->ctx.cli.i0;
+ if (!next_key) {
+ chunk_printf(&trash, "%p: %s (shctx:%p, available blocks:%d)\n", cache, cache->id, shctx_ptr(cache), shctx_ptr(cache)->nbav);
+ if (ci_putchk(si_ic(si), &trash) == -1) {
+ si_applet_cant_put(si);
+ return 0;
+ }
+ }
appctx->ctx.cli.p0 = cache;
@@ -987,11 +989,12 @@ static int cli_io_handler_show_cache(struct appctx *appctx)
node = eb32_lookup_ge(&cache->entries, next_key);
if (!node) {
shctx_unlock(shctx_ptr(cache));
+ appctx->ctx.cli.i0 = 0;
break;
}
entry = container_of(node, struct cache_entry, eb);
- chunk_appendf(&trash, "%p hash:%u size:%u (%u blocks), refcount:%u, expire:%d\n", entry, (*(unsigned int *)entry->hash), block_ptr(entry)->len, block_ptr(entry)->block_count, block_ptr(entry)->refcount, entry->expire - (int)now.tv_sec);
+ chunk_printf(&trash, "%p hash:%u size:%u (%u blocks), refcount:%u, expire:%d\n", entry, (*(unsigned int *)entry->hash), block_ptr(entry)->len, block_ptr(entry)->block_count, block_ptr(entry)->refcount, entry->expire - (int)now.tv_sec);
next_key = node->key + 1;
appctx->ctx.cli.i0 = next_key;