diff options
| author | Tom Lane <tgl@sss.pgh.pa.us> | 2020-11-25 11:40:44 -0500 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2020-11-25 11:40:44 -0500 |
| commit | 2432b1a04087edc2fd9536c7c9aa4ca03fd1b363 (patch) | |
| tree | 4540b2dc58b1e75c8341f4268b69de1a5d5977c9 /src/include/utils/guc_tables.h | |
| parent | f73999262ed6c40d9a7c3d7cccec7143d4d15287 (diff) | |
Avoid spamming the client with multiple ParameterStatus messages.
Up to now, we sent a ParameterStatus message to the client immediately
upon any change in the active value of any GUC_REPORT variable. This
was only barely okay when the feature was designed; now that we have
things like function SET clauses, there are very plausible use-cases
where a GUC_REPORT variable might change many times within a query
--- and even end up back at its original value, perhaps. Fortunately
most of our GUC_REPORT variables are unlikely to be changed often;
but there are proposals in play to enlarge that set, or even make it
user-configurable.
Hence, let's fix things to not generate more than one ParameterStatus
message per variable per query, and to not send any message at all
unless the end-of-query value is different from what we last reported.
Discussion: https://postgr.es/m/5708.1601145259@sss.pgh.pa.us
Diffstat (limited to 'src/include/utils/guc_tables.h')
| -rw-r--r-- | src/include/utils/guc_tables.h | 5 |
1 files changed, 4 insertions, 1 deletions
diff --git a/src/include/utils/guc_tables.h b/src/include/utils/guc_tables.h index 04431d0eb25..7f36e1146f2 100644 --- a/src/include/utils/guc_tables.h +++ b/src/include/utils/guc_tables.h @@ -161,6 +161,8 @@ struct config_generic GucContext reset_scontext; /* context that set the reset value */ GucStack *stack; /* stacked prior values */ void *extra; /* "extra" pointer for current actual value */ + char *last_reported; /* if variable is GUC_REPORT, value last sent + * to client (NULL if not yet sent) */ char *sourcefile; /* file current setting is from (NULL if not * set in config file) */ int sourceline; /* line in source file */ @@ -172,7 +174,8 @@ struct config_generic * Caution: the GUC_IS_IN_FILE bit is transient state for ProcessConfigFile. * Do not assume that its value represents useful information elsewhere. */ -#define GUC_PENDING_RESTART 0x0002 +#define GUC_PENDING_RESTART 0x0002 /* changed value cannot be applied yet */ +#define GUC_NEEDS_REPORT 0x0004 /* new value must be reported to client */ /* GUC records for specific variable types */ |