[libvirt] [PATCH v2] lib: Add note that bulk stats API queries may overrun RPC buffers

Peter Krempa pkrempa at redhat.com
Tue May 23 14:23:30 UTC 2017


Hint that the users should limit the number of VMs queried in the bulk
stats API.
---
v2:
- added a suggestion of the number of queried VMs (valid after bump to 32M message)

 src/libvirt-domain.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/src/libvirt-domain.c b/src/libvirt-domain.c
index 310b91b37..aef061943 100644
--- a/src/libvirt-domain.c
+++ b/src/libvirt-domain.c
@@ -11315,6 +11315,10 @@ virConnectGetDomainCapabilities(virConnectPtr conn,
  * VIR_CONNECT_GET_ALL_DOMAINS_STATS_SHUTOFF and/or
  * VIR_CONNECT_GET_ALL_DOMAINS_STATS_OTHER for all other states.
  *
+ * Note that this API is prone to exceeding maximum RPC message size on hosts
+ * with lots of VMs so it's suggested to use virDomainListGetStats with a
+ * reasonable list of VMs as the argument.
+ *
  * Returns the count of returned statistics structures on success, -1 on error.
  * The requested data are returned in the @retStats parameter. The returned
  * array should be freed by the caller. See virDomainStatsRecordListFree.
@@ -11386,6 +11390,10 @@ virConnectGetAllDomainStats(virConnectPtr conn,
  * Note that any of the domain list filtering flags in @flags may be rejected
  * by this function.
  *
+ * Note that this API is prone to exceeding maximum RPC if querying too many VMs
+ * with lots of statistics. It's suggested to query in batches of 10VMs, which
+ * should be good enough for VMs with 3000 disks + networks.
+ *
  * Returns the count of returned statistics structures on success, -1 on error.
  * The requested data are returned in the @retStats parameter. The returned
  * array should be freed by the caller. See virDomainStatsRecordListFree.
-- 
2.12.2




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