curl-library

From: Ricardo Mota via curl-library <curl-library_at_cool.haxx.se> Date: Wed, 6 Feb 2019 09:37:39 +0000

-- 
*Ricardo Mota*
ricardoflmota_at_gmail.com
Phone : +351 924 421 971
Skype : rfl.mota
On Mon, Feb 4, 2019 at 3:41 PM Chris Carlmar via curl-library <
curl-library_at_cool.haxx.se> wrote:
> On 04.02.2019 15:41, Ricardo Mota via curl-library wrote:
> > Hello Daniel, thank you for your reply.
> >
> > This is the build configuration I've used for an ARMv6 linux embedded
> > target:
> >
> >         /Host setup:       arm-none-linux-gnueabi/
> >
> >         /  Compiler:         arm-none-linux-gnueabi-gcc/
> >
> >         /   CFLAGS:          -Werror-implicit-function-declaration -O2
> >         -Wno-system-headers -pthread/
> >
> >         /   LIBS:            -lssl -lcrypto -lz -lrt/
> >
> >         /
> >         /
> >
> >         /  curl version:     7.64.0-DEV/
> >
> >         /  SSL support:      enabled (OpenSSL)/
> >
> >         /  SSH support:      no      (--with-libssh2)/
> >
> >         /  zlib support:     enabled/
> >
> >         /  brotli support:   no      (--with-brotli)/
> >
> >         /  GSS-API support:  no      (--with-gssapi)/
> >
> >         /  TLS-SRP support:  enabled/
> >
> >         /  resolver:         POSIX threaded/
> >
> >         /  IPv6 support:     enabled/
> >
> >         /  Unix sockets support: enabled/
> >
> >         /  IDN support:      no      (--with-{libidn2,winidn})/
> >
> >         /  Build libcurl:    Shared=no, Static=yes/
> >
> >         /  Built-in manual:  enabled/
> >
> >         /  --libcurl option: enabled (--disable-libcurl-option)/
> >
> >         /  Verbose errors:   enabled (--disable-verbose)/
> >
> >         /  SSPI support:     no      (--enable-sspi)/
> >
> >         /  ca cert bundle:   no/
> >
> >         /  ca cert path:     no/
> >
> >         /  ca fallback:      no/
> >
> >         /  LDAP support:     no      (--enable-ldap / --with-ldap-lib /
> >         --with-lber-lib)/
> >
> >         /  LDAPS support:    no      (--enable-ldaps)/
> >
> >         /  RTSP support:     enabled/
> >
> >         /  RTMP support:     no      (--with-librtmp)/
> >
> >         /  metalink support: no      (--with-libmetalink)/
> >
> >         /  PSL support:      no      (libpsl not found)/
> >
> >         /  HTTP2 support:    disabled (--with-nghttp2)/
> >
> >         /  Protocols:        DICT FILE FTP FTPS GOPHER HTTP HTTPS IMAP
> >         IMAPS POP3 POP3S RTSP SMB SMBS SMTP SMTPS TELNET TFTP/
> >
> >
> > I've used the following /"wrapper"
> > (https://github.com/mrtazz/restclient-cpp)/ for /libcurl/ just doing
> the
> > initialization of an object /connection /and querying a simple REST
> service.
> >
> > I've already tried compiling without /zlib/ or /SSL /support, thinking
> > it could be a problem related with ssl library version I was using, but
> > the problem persisted.
> >
> > I can't get you an exact value for the memory consumption because I
> > don't have many debug tools for the target system but I can see the
> > memory increasing 4KB ~ 10 sec. The only thing I noticed is that if I
> > use direct IP for the connection (without the name resolution), the
> > problem goes away, and the memory only seems to increase when the
> > network is down and the connection fails to resolve the name:
> >
> >         /Could not resolve host: abc.com <http://abc.com/>/
> >
> >         /* Closing connection XXXX/
> >
> >
> > I've already tried with different /7.xx /versions of /libcurl /but the
> > behavior is the same in all.
> >
> > Any other information I can provide to help debug the issue?
> >
> >
> >
> > On Mon, Feb 4, 2019 at 1:25 PM Daniel Stenberg <daniel_at_haxx.se
> > <mailto:daniel_at_haxx.se>> wrote:
> >
> >     On Mon, 4 Feb 2019, Ricardo Mota via curl-library wrote:
> >
> >      > I'm experiencing a problem using *libcurl *due to a memory
> >     consumption
> >      > increase in my application which queries a simple REST API in a
> loop
> >      > reusing the same handle. Doing some tests, I only notice this
> memory
> >      > increase when I'm using name resolution and specifically when the
> >     network
> >      > is down. I've already tried to disable DNS cache by setting
> >      > *CURLOPT_DNS_CACHE_TIMEOUT
> >      > *value to 0 but the problem seems to persist. Can somebody please
> >     help me
> >      > debugging this problem?
> >
> >     What level of memory consumption increase are we talking about?
> >
> >     What libcurl version on what platform?
> >
> >     I don't think what you're describing is a particularly strong
> >     indication that
> >     the increase is indeed the DNS cache, and in fact since the cache is
> >     used to
> >     store name to address data and you say you use it in a loop so
> >     surely you just
> >     store the same name over and over (or even just reuse the cached
> >     content)?
> >
> >     so... how can we reproduce this issue?
> >
> >     --
> >
> >        / daniel.haxx.se <http://daniel.haxx.se>
> >
> >
>
> I had a simular issue using libcurl on an embedded system, leaking when
> DNS could not be reached. It turned out to be a memory leak in the
> version of glibc, which I could not change.
>
> Ended up changing to c-ares, and that stopped the leaking.
>
> --
> mvh
> Chris Carlmar
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curl-library

Re: Memory consumption of DNS cache when network is down?