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Emit parameter values during query bind/execute errors

Browse Source 
This makes such log entries more useful, since the cause of the error
can be dependent on the parameter values.

Author: Alexey Bashtanov, Álvaro Herrera
Discussion: https://postgr.es/m/0146a67b-a22a-0519-9082-bc29756b93a2@imap.cc
Reviewed-by: Peter Eisentraut, Andres Freund, Tom Lane
This commit is contained in:
Alvaro Herrera
2019-12-11 18:03:35 -03:00
parent 16114f2ea0
commit ba79cb5dc8
8 changed files with 271 additions and 47 deletions
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110
src/backend/nodes/params.c
View File

@ -15,11 +15,14 @@
#include "postgres.h"
#include "access/xact.h"
#include "mb/stringinfo_mb.h"
#include "nodes/bitmapset.h"
#include "nodes/params.h"
#include "storage/shmem.h"
#include "utils/datum.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
/*
@ -44,6 +47,7 @@ makeParamList(int numParams)
retval->paramCompileArg = NULL;
retval->parserSetup = NULL;
retval->parserSetupArg = NULL;
retval->paramValuesStr = NULL;
retval->numParams = numParams;
return retval;
@ -58,6 +62,8 @@ makeParamList(int numParams)
* set of parameter values. If dynamic parameter hooks are present, we
* intentionally do not copy them into the result. Rather, we forcibly
* instantiate all available parameter values and copy the datum values.
*
* paramValuesStr is not copied, either.
*/
ParamListInfo
copyParamList(ParamListInfo from)
@ -158,6 +164,8 @@ EstimateParamListSpace(ParamListInfo paramLI)
* RestoreParamList can be used to recreate a ParamListInfo based on the
* serialized representation; this will be a static, self-contained copy
* just as copyParamList would create.
*
* paramValuesStr is not included.
*/
void
SerializeParamList(ParamListInfo paramLI, char **start_address)
@ -251,3 +259,105 @@ RestoreParamList(char **start_address)
return paramLI;
}
/*
* BuildParamLogString
* Return a string that represent 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 not zero, that's the maximum number of characters of the
* input string printed; an ellipsis is added if more characters exist.
* (Added quotes are not considered.)
*/
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 unsuitable.
*/
/*
* 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);
}
}
}
MemoryContextSwitchTo(oldCxt);
MemoryContextDelete(tmpCxt);
return buf.data;
}
/*
* ParamsErrorCallback - callback for printing parameters in error context
*
* Note that this is a no-op unless BuildParamLogString has been called
* beforehand.
*/
void
ParamsErrorCallback(void *arg)
{
ParamsErrorCbData *data = (ParamsErrorCbData *) arg;
if (data == NULL ||
data->params == NULL ||
data->params->paramValuesStr == NULL)
return;
if (data->portalName && data->portalName[0] != '\0')
errcontext("extended query \"%s\" with parameters: %s",
data->portalName, data->params->paramValuesStr);
else
errcontext("extended query with parameters: %s",
data->params->paramValuesStr);
}

119
src/backend/tcop/postgres.c
View File

@ -1614,6 +1614,8 @@ exec_bind_message(StringInfo input_message)
bool save_log_statement_stats = log_statement_stats;
bool snapshot_set = false;
char msec_str[32];
ParamsErrorCbData params_data;
ErrorContextCallback params_errcxt;
/* Get the fixed part of the message */
portal_name = pq_getmsgstring(input_message);
@ -1753,6 +1755,8 @@ exec_bind_message(StringInfo input_message)
*/
if (numParams > 0)
{
char **knownTextValues = NULL; /* allocate on first use */
params = makeParamList(numParams);
for (int paramno = 0; paramno < numParams; paramno++)
@ -1820,9 +1824,32 @@ exec_bind_message(StringInfo input_message)
pval = OidInputFunctionCall(typinput, pstring, typioparam, -1);
/* Free result of encoding conversion, if any */
if (pstring && pstring != pbuf.data)
pfree(pstring);
/*
* Free result of encoding conversion, if any, and save a copy
* for later when logging parameters.
*/
if (pstring)
{
if (log_parameters_on_error)
{
MemoryContext oldcxt;
oldcxt = MemoryContextSwitchTo(MessageContext);
if (knownTextValues == NULL)
knownTextValues =
palloc0(numParams * sizeof(char *));
/*
* Note: must copy at least two more full characters
* than BuildParamLogString wants to see; otherwise it
* might fail to include the ellipsis.
*/
knownTextValues[paramno] =
pnstrdup(pstring, 64 + 2 * MAX_MULTIBYTE_CHAR_LEN);
MemoryContextSwitchTo(oldcxt);
}
if (pstring != pbuf.data)
pfree(pstring);
}
}
else if (pformat == 1) /* binary mode */
{
@ -1872,6 +1899,15 @@ exec_bind_message(StringInfo input_message)
params->params[paramno].pflags = PARAM_FLAG_CONST;
params->params[paramno].ptype = ptype;
}
/*
* Once all parameters have been received, prepare for printing them in
* errors, if configured to do so. (This is saved in the portal, so
* that they'll appear when the query is executed later.)
*/
if (log_parameters_on_error)
params->paramValuesStr =
BuildParamLogString(params, knownTextValues, 64);
}
else
params = NULL;
@ -1879,6 +1915,14 @@ exec_bind_message(StringInfo input_message)
/* Done storing stuff in portal's context */
MemoryContextSwitchTo(oldContext);
/* Set the error callback so that parameters are logged, as needed */
params_data.portalName = portal->name;
params_data.params = params;
params_errcxt.previous = error_context_stack;
params_errcxt.callback = ParamsErrorCallback;
params_errcxt.arg = (void *) &params_data;
error_context_stack = &params_errcxt;
/* Get the result format codes */
numRFormats = pq_getmsgint(input_message, 2);
if (numRFormats > 0)
@ -1924,6 +1968,12 @@ exec_bind_message(StringInfo input_message)
*/
PortalSetResultFormat(portal, numRFormats, rformats);
/*
* Done binding; remove the parameters error callback. Entries emitted
* later determine independently whether to log the parameters or not.
*/
error_context_stack = error_context_stack->previous;
/*
* Send BindComplete.
*/
@ -1980,6 +2030,8 @@ exec_execute_message(const char *portal_name, long max_rows)
bool execute_is_fetch;
bool was_logged = false;
char msec_str[32];
ParamsErrorCbData params_data;
ErrorContextCallback params_errcxt;
/* Adjust destination to tell printtup.c what to do */
dest = whereToSendOutput;
@ -2104,8 +2156,16 @@ exec_execute_message(const char *portal_name, long max_rows)
CHECK_FOR_INTERRUPTS();
/*
* Okay to run the portal.
* Okay to run the portal. Set the error callback so that parameters are
* logged. The parameters must have been saved during the bind phase.
*/
params_data.portalName = portal->name;
params_data.params = portalParams;
params_errcxt.previous = error_context_stack;
params_errcxt.callback = ParamsErrorCallback;
params_errcxt.arg = (void *) &params_data;
error_context_stack = &params_errcxt;
if (max_rows <= 0)
max_rows = FETCH_ALL;
@ -2119,6 +2179,9 @@ exec_execute_message(const char *portal_name, long max_rows)
receiver->rDestroy(receiver);
/* Done executing; remove the params error callback */
error_context_stack = error_context_stack->previous;
if (completed)
{
if (is_xact_command)
@ -2329,51 +2392,13 @@ errdetail_execute(List *raw_parsetree_list)
static int
errdetail_params(ParamListInfo params)
{
/* We mustn't call user-defined I/O functions when in an aborted xact */
if (params && params->numParams > 0 && !IsAbortedTransactionBlockState())
if (params && params->numParams > 0)
{
StringInfoData param_str;
MemoryContext oldcontext;
char *str;
/* This code doesn't support dynamic param lists */
Assert(params->paramFetch == NULL);
/* Make sure any trash is generated in MessageContext */
oldcontext = MemoryContextSwitchTo(MessageContext);
initStringInfo(&param_str);
for (int paramno = 0; paramno < params->numParams; paramno++)
{
ParamExternData *prm = &params->params[paramno];
Oid typoutput;
bool typisvarlena;
char *pstring;
appendStringInfo(&param_str, "%s$%d = ",
paramno > 0 ? ", " : "",
paramno + 1);
if (prm->isnull || !OidIsValid(prm->ptype))
{
appendStringInfoString(&param_str, "NULL");
continue;
}
getTypeOutputInfo(prm->ptype, &typoutput, &typisvarlena);
pstring = OidOutputFunctionCall(typoutput, prm->value);
appendStringInfoStringQuoted(&param_str, pstring, 0);
pfree(pstring);
}
errdetail("parameters: %s", param_str.data);
pfree(param_str.data);
MemoryContextSwitchTo(oldcontext);
str = BuildParamLogString(params, NULL, 0);
if (str && str[0] != '\0')
errdetail("parameters: %s", str);
}
return 0;

10
src/backend/utils/misc/guc.c
View File

@ -486,6 +486,7 @@ extern const struct config_enum_entry dynamic_shared_memory_options[];
* GUC option variables that are exported from this module
*/
bool log_duration = false;
bool log_parameters_on_error = false;
bool Debug_print_plan = false;
bool Debug_print_parse = false;
bool Debug_print_rewritten = false;
@ -1300,6 +1301,15 @@ static struct config_bool ConfigureNamesBool[] =
false,
NULL, NULL, NULL
},
{
{"log_parameters_on_error", PGC_SUSET, LOGGING_WHAT,
gettext_noop("Logs bind parameters of the logged statements where possible."),
NULL
},
&log_parameters_on_error,
false,
NULL, NULL, NULL
},
{
{"debug_print_parse", PGC_USERSET, LOGGING_WHAT,
gettext_noop("Logs each query's parse tree."),

1
src/backend/utils/misc/postgresql.conf.sample
View File

@ -544,6 +544,7 @@
# e.g. '<%u%%%d> '
#log_lock_waits = off # log lock waits >= deadlock_timeout
#log_statement = 'none' # none, ddl, mod, all
#log_parameters_on_error = off # on error log statements with bind parameters
#log_replication_commands = off
#log_temp_files = -1 # log temporary files equal or larger
# than the specified size in kilobytes;

44
src/bin/pgbench/t/001_pgbench_with_server.pl
View File

@ -270,6 +270,50 @@ COMMIT;
}
});
# Verify server logging of parameters.
$node->append_conf('postgresql.conf', "log_parameters_on_error = true");
$node->reload;
pgbench(
'-n -t1 -c1 -M prepared',
2,
[],
[
qr{ERROR: division by zero},
qr{CONTEXT: extended query with parameters: \$1 = '1', \$2 = NULL}
],
'server parameter logging',
{
'001_param_1' => q{select '1' as one \gset
SELECT 1 / (random() / 2)::int, :one::int, :two::int;
}
});
$node->append_conf('postgresql.conf', "log_min_duration_statement = 0");
$node->reload;
pgbench(
'-n -t1 -c1 -M prepared',
2,
[],
[
qr{ERROR: invalid input syntax for type json},
qr[CONTEXT: JSON data, line 1: \{ invalid\.\.\.
extended query with parameters: \$1 = '\{ invalid ', \$2 = '''Valame Dios!'' dijo Sancho; ''no le dije yo a vuestra merced que ...'$]m
],
'server parameter logging',
{
'001_param_2' => q[select '{ invalid ' as value \gset
select $$'Valame Dios!' dijo Sancho; 'no le dije yo a vuestra merced que mirase bien lo que hacia?'$$ as long \gset
select column1::jsonb from (values (:value), (:long)) as q;
]
});
my $log = TestLib::slurp_file($node->logfile);
like($log, qr[DETAIL: parameters: \$1 = '\{ invalid ', \$2 = '''Valame Dios!'' dijo Sancho; ''no le dije yo a vuestra merced que mirase bien lo que hacia\?'''],
"parameter report does not truncate");
$log = undef;
$node->append_conf('postgresql.conf', "log_min_duration_statement = -1");
$node->reload;
# test expressions
# command 1..3 and 23 depend on random seed which is used to call srandom.
pgbench(

10
src/include/nodes/params.h
View File

@ -115,6 +115,7 @@ typedef struct ParamListInfoData
void *paramCompileArg;
ParserSetupHook parserSetup; /* parser setup hook */
void *parserSetupArg;
char *paramValuesStr; /* params as a single string for errors */
int numParams; /* nominal/maximum # of Params represented */
/*
@ -149,6 +150,12 @@ typedef struct ParamExecData
bool isnull;
} ParamExecData;
/* type of argument for ParamsErrorCallback */
typedef struct ParamsErrorCbData
{
const char *portalName;
ParamListInfo params;
} ParamsErrorCbData;
/* Functions found in src/backend/nodes/params.c */
extern ParamListInfo makeParamList(int numParams);
@ -156,5 +163,8 @@ extern ParamListInfo copyParamList(ParamListInfo from);
extern Size EstimateParamListSpace(ParamListInfo paramLI);
extern void SerializeParamList(ParamListInfo paramLI, char **start_address);
extern ParamListInfo RestoreParamList(char **start_address);
extern char *BuildParamLogString(ParamListInfo params, char **paramTextValues,
int valueLen);
extern void ParamsErrorCallback(void *arg);
#endif /* PARAMS_H */

1
src/include/utils/guc.h
View File

@ -234,6 +234,7 @@ typedef enum
/* GUC vars that are actually declared in guc.c, rather than elsewhere */
extern bool log_duration;
extern bool log_parameters_on_error;
extern bool Debug_print_plan;
extern bool Debug_print_parse;
extern bool Debug_print_rewritten;