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authorThomas Munro <tmunro@postgresql.org>2019-10-17 13:24:50 +1300
committerThomas Munro <tmunro@postgresql.org>2019-10-17 13:50:59 +1300
commitcdbb3921308ec71e7d090b734a1c8c0bf3269088 (patch)
treee8c9a613d229fd41661c34e997f33e3836538170 /src
parentc1443eebe5a83449ef24d53eb52f7c176c420f71 (diff)
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
Diffstat (limited to 'src')
-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 07447d35e3f..569439fec75 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -9034,6 +9034,21 @@ 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.
@@ -9051,6 +9066,7 @@ 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++)
@@ -9063,9 +9079,16 @@ 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);
@@ -9078,6 +9101,9 @@ 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)
@@ -9086,7 +9112,10 @@ 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;
}
/*