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authorThomas Munro <tmunro@postgresql.org>2019-10-17 13:24:50 +1300
committerThomas Munro <tmunro@postgresql.org>2019-10-17 13:58:58 +1300
commit6737111a7ae1fac6b4781250be7c0719c5a7ed48 (patch)
tree0e6aa73116bd8aa6a656bbb048b17728df7d1539
parent6f1e336de01003e4005a9c00f6c25c94ccd4dd34 (diff)
downloadpostgresql-6737111a7ae1fac6b4781250be7c0719c5a7ed48.tar.gz
postgresql-6737111a7ae1fac6b4781250be7c0719c5a7ed48.zip
When restoring GUCs in parallel workers, show an error context.
Otherwise it can be hard to see where an error is coming from, when the parallel worker sets all the GUCs that it received from the leader. Bug #15726. Back-patch to 9.5, where RestoreGUCState() appeared. Reported-by: Tiago Anastacio Reviewed-by: Daniel Gustafsson, Tom Lane Discussion: https://postgr.es/m/15726-6d67e4fa14f027b3%40postgresql.org
-rw-r--r--src/backend/utils/misc/guc.c29
1 files changed, 29 insertions, 0 deletions
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index f88386f0486..eca51a7c4eb 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -9595,6 +9595,21 @@ read_gucstate_binary(char **srcptr, char *srcend, void *dest, Size size)
}
/*
+ * Callback used to add a context message when reporting errors that occur
+ * while trying to restore GUCs in parallel workers.
+ */
+static void
+guc_restore_error_context_callback(void *arg)
+{
+ char **error_context_name_and_value = (char **) arg;
+
+ if (error_context_name_and_value)
+ errcontext("while setting parameter \"%s\" to \"%s\"",
+ error_context_name_and_value[0],
+ error_context_name_and_value[1]);
+}
+
+/*
* RestoreGUCState:
* Reads the GUC state at the specified address and updates the GUCs with the
* values read from the GUC state.
@@ -9612,6 +9627,7 @@ RestoreGUCState(void *gucstate)
char *srcend;
Size len;
int i;
+ ErrorContextCallback error_context_callback;
/* See comment at can_skip_gucvar(). */
for (i = 0; i < num_guc_variables; i++)
@@ -9624,9 +9640,16 @@ RestoreGUCState(void *gucstate)
srcptr += sizeof(len);
srcend = srcptr + len;
+ /* If the GUC value check fails, we want errors to show useful context. */
+ error_context_callback.callback = guc_restore_error_context_callback;
+ error_context_callback.previous = error_context_stack;
+ error_context_callback.arg = NULL;
+ error_context_stack = &error_context_callback;
+
while (srcptr < srcend)
{
int result;
+ char *error_context_name_and_value[2];
varname = read_gucstate(&srcptr, srcend);
varvalue = read_gucstate(&srcptr, srcend);
@@ -9641,6 +9664,9 @@ RestoreGUCState(void *gucstate)
read_gucstate_binary(&srcptr, srcend,
&varscontext, sizeof(varscontext));
+ error_context_name_and_value[0] = varname;
+ error_context_name_and_value[1] = varvalue;
+ error_context_callback.arg = &error_context_name_and_value[0];
result = set_config_option(varname, varvalue, varscontext, varsource,
GUC_ACTION_SET, true, ERROR, true);
if (result <= 0)
@@ -9649,7 +9675,10 @@ RestoreGUCState(void *gucstate)
errmsg("parameter \"%s\" could not be set", varname)));
if (varsourcefile[0])
set_config_sourcefile(varname, varsourcefile, varsourceline);
+ error_context_callback.arg = NULL;
}
+
+ error_context_stack = error_context_callback.previous;
}
/*