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Add sleep to execute_cmd_time_limit

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If the query fails instantly, the retries end up busy-looping. Now
each try is at least one second.
This commit is contained in:
Esa Korhonen 2018-10-04 16:29:13 +03:00
parent 707506feae
commit a398da58a4
1 changed files with 12 additions and 1 deletions
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13
server/modules/monitor/mariadbmon/mariadbserver.cc
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@ -187,14 +187,19 @@ bool MariaDBServer::execute_cmd_time_limit(const std::string& cmd, maxbase::Dura
std::string* errmsg_out)
{
StopWatch timer;
// If a query lasts less than 1s, sleep so that at most 1 query/s is sent.
// This prevents busy-looping when faced with some network errors.
const Duration min_query_time(1.0);
// Even if time is up, try at least once.
bool cmd_success = false;
bool keep_trying = true;
while (!cmd_success && keep_trying)
{
StopWatch query_timer;
string error_msg;
unsigned int errornum = 0;
cmd_success = execute_cmd_no_retry(cmd, &error_msg, &errornum);
auto query_time = query_timer.lap();
// Check if there is time to retry.
Duration time_remaining = time_limit - timer.split();
@ -203,8 +208,14 @@ bool MariaDBServer::execute_cmd_time_limit(const std::string& cmd, maxbase::Dura
{
if (keep_trying)
{
MXS_WARNING("Query '%s' failed on '%s': %s Retrying with %.1f seconds left.",
MXS_WARNING("Query '%s' failed on %s: %s Retrying with %.1f seconds left.",
cmd.c_str(), name(), error_msg.c_str(), time_remaining.secs());
if (query_time < min_query_time)
{
Duration query_sleep = min_query_time - query_time;
Duration this_sleep = MXS_MIN(time_remaining, query_sleep);
std::this_thread::sleep_for(this_sleep);
}
}
else if (errmsg_out)
{