Function BuildParamLogString

src/backend/nodes/params.c:334–398

* BuildParamLogString * Return a string that represents the parameter list, for logging. * * If caller already knows textual representations for some parameters, it can * pass an array of exactly params->numParams values as knownTextValues, which * can contain NULLs for any unknown individual values. NULL can be given if * no parameters are known. * * If maxlen is >= 0, that's the maximu

 * longer.  (Added quotes are not considered in this calculation.)
 */
char *
BuildParamLogString(ParamListInfo params, char **knownTextValues, int maxlen)
{
	MemoryContext tmpCxt,
				oldCxt;
	StringInfoData buf;

	/*
	 * NB: think not of returning params->paramValuesStr!  It may have been
	 * generated with a different maxlen, and so be unsuitable.  Besides that,
	 * this is the function used to create that string.
	 */

	/*
	 * No work if the param fetch hook is in use.  Also, it's not possible to
	 * do this in an aborted transaction.  (It might be possible to improve on
	 * this last point when some knownTextValues exist, but it seems tricky.)
	 */
	if (params->paramFetch != NULL ||
		IsAbortedTransactionBlockState())
		return NULL;

	/* Initialize the output stringinfo, in caller's memory context */
	initStringInfo(&buf);

	/* Use a temporary context to call output functions, just in case */
	tmpCxt = AllocSetContextCreate(CurrentMemoryContext,
								   "BuildParamLogString",
								   ALLOCSET_DEFAULT_SIZES);
	oldCxt = MemoryContextSwitchTo(tmpCxt);

	for (int paramno = 0; paramno < params->numParams; paramno++)
	{
		ParamExternData *param = &params->params[paramno];

		appendStringInfo(&buf,
						 "%s$%d = ",
						 paramno > 0 ? ", " : "",
						 paramno + 1);

		if (param->isnull || !OidIsValid(param->ptype))
			appendStringInfoString(&buf, "NULL");
		else
		{
			if (knownTextValues != NULL && knownTextValues[paramno] != NULL)
				appendStringInfoStringQuoted(&buf, knownTextValues[paramno],
											 maxlen);
			else
			{
				Oid			typoutput;
				bool		typisvarlena;
				char	   *pstring;

				getTypeOutputInfo(param->ptype, &typoutput, &typisvarlena);
				pstring = OidOutputFunctionCall(typoutput, param->value);
				appendStringInfoStringQuoted(&buf, pstring, maxlen);
			}
		}