On 2019-Dec-07, Tom Lane wrote:
> 0002:
Here's a version of this part with fixes for these comments. It applies
on top of the stringinfo_mb.c patch sent elsewhere in the thread.
(If we were to add a "log_parameters_on_error_max_length" GUC to decide
the length to log, we would get rid of the remaining magical numbers in
this code).
> Seems like BuildParamLogString's "valueLen" parameter ought to be called
> "maxlen", for consistency with 0001 and because "valueLen" is at best
> misleading about what the parameter means.
>
> I'd toss the enlargeStringInfo call here too, as it seems overly
> complicated and underly correct or useful.
>
> Probably doing MemoryContextReset after each parameter (even the last one!)
> is a net loss compared to just letting it go till the end. Although
> I'd be inclined to use ALLOCSET_DEFAULT_SIZES not SMALL_SIZES if you
> do it like that.
>
> Please do not throw away the existing comment "/* Free result of encoding
> conversion, if any */" in exec_bind_message.
>
> As above, this risks generating partial multibyte characters. You might
> be able to get away with letting appendStringInfoStringQuoted do the
> multibyte-aware truncation, but you probably have to copy more than just
> one more extra byte first.
>
> I have zero faith in this:
>
> + params_errcxt.arg = (void *) &((ParamsErrorCbData)
> + { portal->name, params });
>
> How do you know where the compiler is putting that value, ie what
> its lifespan is going to be? Better to use an explicit variable.
>
> I concur with dropping testlibpq5.
>
> regards, tom lane
--
Álvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
>From 45eca917877ea72122478fded75d5722a18d92aa Mon Sep 17 00:00:00 2001
From: Alvaro Herrera <[email protected]>
Date: Mon, 2 Dec 2019 16:02:48 -0300
Subject: [PATCH v21 2/2] Emit parameter values during query bind/execute
errors
---
doc/src/sgml/config.sgml | 23 ++++
src/backend/nodes/params.c | 114 +++++++++++++++++
src/backend/tcop/postgres.c | 118 +++++++++++-------
src/backend/utils/misc/guc.c | 10 ++
src/backend/utils/misc/postgresql.conf.sample | 1 +
src/bin/pgbench/t/001_pgbench_with_server.pl | 35 ++++++
src/include/nodes/params.h | 10 ++
src/include/utils/guc.h | 1 +
8 files changed, 265 insertions(+), 47 deletions(-)
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 53ac14490a..5d1c90282f 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -6595,6 +6595,29 @@ log_line_prefix = '%m [%p] %q%u@%d/%a '
</listitem>
</varlistentry>
+ <varlistentry id="guc-log-parameters-on-error" xreflabel="log_parameters_on_error">
+ <term><varname>log_parameters_on_error</varname> (<type>boolean</type>)
+ <indexterm>
+ <primary><varname>log_parameters_on_error</varname> configuration parameter</primary>
+ </indexterm>
+ </term>
+ <listitem>
+ <para>
+ Controls whether bind parameters are logged when a statement is logged
+ as a result of <xref linkend="guc-log-min-error-statement"/>.
+ It adds some overhead, as postgres will compute and store textual
+ representations of parameter values in memory for all statements,
+ even if they eventually do not get logged.
+ This setting has no effect on statements logged due to
+ <xref linkend="guc-log-min-duration-statement"/> or
+ <xref linkend="guc-log-statement"/> settings, as they are always logged
+ with parameters.
+ The default is <literal>off</literal>.
+ Only superusers can change this setting.
+ </para>
+ </listitem>
+ </varlistentry>
+
<varlistentry id="guc-log-statement" xreflabel="log_statement">
<term><varname>log_statement</varname> (<type>enum</type>)
<indexterm>
diff --git a/src/backend/nodes/params.c b/src/backend/nodes/params.c
index cf4387e40f..c3320ee1c4 100644
--- a/src/backend/nodes/params.c
+++ b/src/backend/nodes/params.c
@@ -15,11 +15,16 @@
#include "postgres.h"
+#include "access/xact.h"
+#include "lib/stringinfo.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"
+#include "utils/portal.h"
/*
@@ -44,6 +49,7 @@ makeParamList(int numParams)
retval->paramCompileArg = NULL;
retval->parserSetup = NULL;
retval->parserSetupArg = NULL;
+ retval->paramValuesStr = NULL;
retval->numParams = numParams;
return retval;
@@ -58,6 +64,8 @@ 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 +166,8 @@ 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 +261,107 @@ RestoreParamList(char **start_address)
return paramLI;
}
+
+/*
+ * BuildParamLogString
+ * Prepare for reporting parameter values.
+ *
+ * Create a string to represent parameters list for logging and save it to
+ * params->paramValuesStr. 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 the individual values not
+ * known. 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.)
+ *
+ * This should only be called if log_parameters_on_error is set, or caller
+ * wants to report the query parameters for other reasons.
+ */
+void
+BuildParamLogString(ParamListInfo params, char **knownTextValues, int maxlen)
+{
+ MemoryContext tmpCxt,
+ oldCxt;
+ StringInfoData buf;
+
+ /*
+ * Nothing to do if it's is already set; also, no work if the param fetch
+ * hook is in use. (Mostly because it's unimplemented ... but that's
+ * because it doesn't seem a case worth pursuing.) Also, avoid calling
+ * user-defined I/O functions when in an aborted transaction. It might
+ * be possible to improve on this when some knownTextValues exist.
+ */
+ if (params->paramValuesStr != NULL ||
+ params->paramFetch != NULL ||
+ IsAbortedTransactionBlockState())
+ return;
+
+ /* 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 = ¶ms->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);
+ }
+ }
+ }
+
+ params->paramValuesStr = buf.data;
+
+ MemoryContextSwitchTo(oldCxt);
+ MemoryContextDelete(tmpCxt);
+}
+
+/*
+ * 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);
+}
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index 512209a38c..5eef1ae41c 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -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 +1899,14 @@ exec_bind_message(StringInfo input_message)
params->params[paramno].pflags = PARAM_FLAG_CONST;
params->params[paramno].ptype = ptype;
}
+
+ /*
+ * Prepare for printing parameters, 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)
+ BuildParamLogString(params, knownTextValues, 64);
}
else
params = NULL;
@@ -1879,6 +1914,14 @@ 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_errcxt.previous = error_context_stack;
+ params_errcxt.callback = ParamsErrorCallback;
+ params_data.portalName = portal->name;
+ params_data.params = params;
+ params_errcxt.arg = (void *) ¶ms_data;
+ error_context_stack = ¶ms_errcxt;
+
/* Get the result format codes */
numRFormats = pq_getmsgint(input_message, 2);
if (numRFormats > 0)
@@ -1924,6 +1967,12 @@ 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 +2029,8 @@ 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 +2155,16 @@ 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_errcxt.previous = error_context_stack;
+ params_errcxt.callback = ParamsErrorCallback;
+ params_data.portalName = portal->name;
+ params_data.params = portalParams;
+ params_errcxt.arg = (void *) ¶ms_data;
+ error_context_stack = ¶ms_errcxt;
+
if (max_rows <= 0)
max_rows = FETCH_ALL;
@@ -2119,6 +2178,9 @@ 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 +2391,13 @@ 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;
+ BuildParamLogString(params, NULL, 0);
- /* This code doesn't support dynamic param lists */
- Assert(params->paramFetch == NULL);
-
- /* Make sure any trash is generated in MessageContext */
- oldcontext = MemoryContextSwitchTo(MessageContext);
-
- initStringInfo(¶m_str);
-
- for (int paramno = 0; paramno < params->numParams; paramno++)
- {
- ParamExternData *prm = ¶ms->params[paramno];
- Oid typoutput;
- bool typisvarlena;
- char *pstring;
-
- appendStringInfo(¶m_str, "%s$%d = ",
- paramno > 0 ? ", " : "",
- paramno + 1);
-
- if (prm->isnull || !OidIsValid(prm->ptype))
- {
- appendStringInfoString(¶m_str, "NULL");
- continue;
- }
-
- getTypeOutputInfo(prm->ptype, &typoutput, &typisvarlena);
-
- pstring = OidOutputFunctionCall(typoutput, prm->value);
-
- appendStringInfoStringQuoted(¶m_str, pstring, 0);
-
- pfree(pstring);
- }
-
- errdetail("parameters: %s", param_str.data);
-
- pfree(param_str.data);
-
- MemoryContextSwitchTo(oldcontext);
+ if (params->paramValuesStr &&
+ params->paramValuesStr[0] != '\0')
+ errdetail("parameters: %s", params->paramValuesStr);
}
return 0;
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index ba74bf9f7d..8d951ce404 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -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."),
diff --git a/src/backend/utils/misc/postgresql.conf.sample b/src/backend/utils/misc/postgresql.conf.sample
index 9541879c1f..087190ce63 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -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;
diff --git a/src/bin/pgbench/t/001_pgbench_with_server.pl b/src/bin/pgbench/t/001_pgbench_with_server.pl
index 1845869016..021d7a1826 100644
--- a/src/bin/pgbench/t/001_pgbench_with_server.pl
+++ b/src/bin/pgbench/t/001_pgbench_with_server.pl
@@ -270,6 +270,41 @@ 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;
+}
+ });
+
+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;
+]
+ });
+
# test expressions
# command 1..3 and 23 depend on random seed which is used to call srandom.
pgbench(
diff --git a/src/include/nodes/params.h b/src/include/nodes/params.h
index fd9046619c..d7a7e1f191 100644
--- a/src/include/nodes/params.h
+++ b/src/include/nodes/params.h
@@ -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 void BuildParamLogString(ParamListInfo params, char **paramTextValues,
+ int valueLen);
+extern void ParamsErrorCallback(void *arg);
#endif /* PARAMS_H */
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index 50098e63fe..41d5e1d14a 100644
--- a/src/include/utils/guc.h
+++ b/src/include/utils/guc.h
@@ -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;
--
2.20.1
