Nice patch, thanks.
I didn't like abusing testlibpq3.c for your new stuff, so I moved it off
to a new file testlibpq5.c. I cleaned up a few other cosmetics things
about this -- v10 attached. I eventually noticed that this patch fails
to initialize each param's textValue to NULL, which probably explains
why you have to be so careful about only setting hasTextValues after the
whole loop. That seems a bit too trusting; I think it would be better
to set all these to NULL in makeParamList instead of leaving the memory
undefined. One way would be to have a for() look in makeParamList that
nullifies the member; another would be to use palloc0().
A third possibility is to inspect each caller of makeParamList and have
them all set textValue to NULL to each parameter.
I'm marking this waiting on author.
--
Álvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
>From 19c80d631694366e8098a564ba347fb1e937056b Mon Sep 17 00:00:00 2001
From: Alvaro Herrera <alvhe...@alvh.no-ip.org>
Date: Wed, 18 Sep 2019 16:56:42 -0300
Subject: [PATCH v10] Allow logging of portal parameters on error
---
doc/src/sgml/config.sgml | 17 ++
src/backend/nodes/params.c | 3 +
src/backend/tcop/postgres.c | 233 +++++++++++++-----
src/backend/utils/error/elog.c | 28 +++
src/backend/utils/misc/guc.c | 10 +
src/backend/utils/misc/postgresql.conf.sample | 1 +
src/include/nodes/params.h | 3 +
src/include/tcop/tcopprot.h | 4 +
src/include/utils/guc.h | 1 +
src/test/README | 3 +-
src/test/examples/Makefile | 2 +-
src/test/examples/testlibpq5.c | 116 +++++++++
12 files changed, 355 insertions(+), 66 deletions(-)
create mode 100644 src/test/examples/testlibpq5.c
diff --git a/doc/src/sgml/config.sgml b/doc/src/sgml/config.sgml
index 6612f95f9f..81dfee5fe7 100644
--- a/doc/src/sgml/config.sgml
+++ b/doc/src/sgml/config.sgml
@@ -6414,6 +6414,23 @@ 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 the statement is logged with bind parameter values.
+ It adds some overhead, as postgres will cache textual
+ representations of parameter values in memory for all statements,
+ even if they eventually do not get logged. 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..00ad6347c7 100644
--- a/src/backend/nodes/params.c
+++ b/src/backend/nodes/params.c
@@ -45,6 +45,7 @@ makeParamList(int numParams)
retval->parserSetup = NULL;
retval->parserSetupArg = NULL;
retval->numParams = numParams;
+ retval->hasTextValues = false;
return retval;
}
@@ -58,6 +59,8 @@ 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.
+ *
+ * We don't bother copying text values, since no caller needs that at present.
*/
ParamListInfo
copyParamList(ParamListInfo from)
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index e8d8e6f828..ec1e4092f5 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -86,6 +86,12 @@
*/
const char *debug_query_string; /* client-supplied query string */
+/*
+ * The top-level portal that the client is immediately working with:
+ * creating, binding, executing, or all at one using simple protocol
+ */
+Portal current_top_portal = NULL;
+
/* Note: whereToSendOutput is initialized for the bootstrap/standalone case */
CommandDest whereToSendOutput = DestDebug;
@@ -1714,6 +1720,9 @@ exec_bind_message(StringInfo input_message)
else
portal = CreatePortal(portal_name, false, false);
+ Assert(current_top_portal == NULL);
+ current_top_portal = portal;
+
/*
* Prepare to copy stuff into the portal's memory context. We do all this
* copying first, because it could possibly fail (out-of-memory) and we
@@ -1751,6 +1760,9 @@ exec_bind_message(StringInfo input_message)
*/
if (numParams > 0)
{
+ /* GUC value can change, so we remember its state to be consistent */
+ bool need_text_values = log_parameters_on_error;
+
params = makeParamList(numParams);
for (int paramno = 0; paramno < numParams; paramno++)
@@ -1818,9 +1830,18 @@ 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);
+ /*
+ * If we need the parameter string, keep it -- possibly making
+ * a copy first, if necessary. Otherwise get rid of it.
+ */
+ if (pstring)
+ {
+ if (need_text_values)
+ params->params[paramno].textValue =
+ pstring == pbuf.data ? pstrdup(pstring) : pstring;
+ else if (pstring != pbuf.data)
+ pfree(pstring);
+ }
}
else if (pformat == 1) /* binary mode */
{
@@ -1846,6 +1867,23 @@ exec_bind_message(StringInfo input_message)
(errcode(ERRCODE_INVALID_BINARY_REPRESENTATION),
errmsg("incorrect binary data format in bind parameter %d",
paramno + 1)));
+
+ /*
+ * Compute textual representation for further logging.
+ *
+ * This could be optimized for certain built-in types, for
+ * which the output function is safe to call even in an
+ * aborted transaction.
+ */
+ if (!isNull && need_text_values)
+ {
+ Oid typoutput;
+ bool typisvarlena;
+
+ getTypeOutputInfo(ptype, &typoutput, &typisvarlena);
+ params->params[paramno].textValue =
+ OidOutputFunctionCall(typoutput, pval);
+ }
}
else
{
@@ -1870,10 +1908,19 @@ exec_bind_message(StringInfo input_message)
params->params[paramno].pflags = PARAM_FLAG_CONST;
params->params[paramno].ptype = ptype;
}
+
+ /* Only now can we safely set this. */
+ params->hasTextValues = need_text_values;
}
else
params = NULL;
+ /*
+ * Set portal parameters early for them to get logged if an error happens
+ * on planning stage
+ */
+ portal->portalParams = params;
+
/* Done storing stuff in portal's context */
MemoryContextSwitchTo(oldContext);
@@ -1954,6 +2001,7 @@ exec_bind_message(StringInfo input_message)
if (save_log_statement_stats)
ShowUsage("BIND MESSAGE STATISTICS");
+ current_top_portal = NULL;
debug_query_string = NULL;
}
@@ -2004,32 +2052,49 @@ exec_execute_message(const char *portal_name, long max_rows)
/* Does the portal contain a transaction command? */
is_xact_command = IsTransactionStmtList(portal->stmts);
- /*
- * We must copy the sourceText and prepStmtName into MessageContext in
- * case the portal is destroyed during finish_xact_command. Can avoid the
- * copy if it's not an xact command, though.
- */
if (is_xact_command)
{
+ /*
+ * We must copy the sourceText and prepStmtName into MessageContext in
+ * case the portal is destroyed during finish_xact_command.
+ */
sourceText = pstrdup(portal->sourceText);
if (portal->prepStmtName)
prepStmtName = pstrdup(portal->prepStmtName);
else
prepStmtName = "<unnamed>";
-
/*
* An xact command shouldn't have any parameters, which is a good
* thing because they wouldn't be around after finish_xact_command.
*/
portalParams = NULL;
+
+ /*
+ * We don't set current top portal for xact cmds, as
+ * 1) the portal may be destroyed earlier than the error happens
+ * 2) it anyway has no parameters in it to log
+ */
+ Assert(current_top_portal == NULL);
}
else
{
+ /*
+ * The portal will remain there until we leave the function, so it's
+ * safe avoid copying and just to refer to the data in its memory
+ * context instead
+ */
sourceText = portal->sourceText;
if (portal->prepStmtName)
prepStmtName = portal->prepStmtName;
else
prepStmtName = "<unnamed>";
+
+ /*
+ * For non-xact commands, we remember the current portal and its bind
+ * parameters for further use in logging
+ */
+ Assert(current_top_portal == NULL);
+ current_top_portal = portal;
portalParams = portal->portalParams;
}
@@ -2178,6 +2243,7 @@ exec_execute_message(const char *portal_name, long max_rows)
if (save_log_statement_stats)
ShowUsage("EXECUTE MESSAGE STATISTICS");
+ current_top_portal = NULL;
debug_query_string = NULL;
}
@@ -2306,61 +2372,21 @@ 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())
+ MemoryContext oldcontext;
+ char *params_message;
+
+ /* Make sure any trash is generated in MessageContext */
+ oldcontext = MemoryContextSwitchTo(MessageContext);
+ params_message = get_portal_bind_params(params);
+
+ if (params_message)
{
- StringInfoData param_str;
- MemoryContext oldcontext;
-
- /* 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;
- char *p;
-
- 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);
-
- appendStringInfoCharMacro(¶m_str, '\'');
- for (p = pstring; *p; p++)
- {
- if (*p == '\'') /* double single quotes */
- appendStringInfoCharMacro(¶m_str, *p);
- appendStringInfoCharMacro(¶m_str, *p);
- }
- appendStringInfoCharMacro(¶m_str, '\'');
-
- pfree(pstring);
- }
-
- errdetail("parameters: %s", param_str.data);
-
- pfree(param_str.data);
-
- MemoryContextSwitchTo(oldcontext);
+ errdetail("parameters: %s", params_message);
+ pfree(params_message);
}
+ MemoryContextSwitchTo(oldcontext);
+
return 0;
}
@@ -2678,6 +2704,86 @@ drop_unnamed_stmt(void)
}
}
+/*
+ * get_portal_bind_params
+ * Get a string containing parameters data -- used for logging.
+ *
+ * Can return NULL if there are no parameters in the portal or the portal is
+ * not valid, or the text representations of the parameters are not available.
+ * If returning a non-NULL value, it allocates memory for the returned string
+ * in the current context, and it's the caller's responsibility to pfree() it.
+ */
+char *
+get_portal_bind_params(ParamListInfo params)
+{
+ StringInfoData param_str;
+
+ /* No parameters to format */
+ if (!params || params->numParams == 0)
+ return NULL;
+
+ /*
+ * We either need textual representation of parameters pre-calculated, or
+ * call potentially user-defined I/O functions to convert the internal
+ * representation into text, which cannot be done in an aborted xact
+ */
+ if (!params->hasTextValues && IsAbortedTransactionBlockState())
+ return NULL;
+
+ initStringInfo(¶m_str);
+
+ /* This code doesn't support dynamic param lists */
+ Assert(params->paramFetch == NULL);
+
+ for (int paramno = 0; paramno < params->numParams; paramno++)
+ {
+ ParamExternData *prm = ¶ms->params[paramno];
+ char *pstring;
+ char *p;
+
+ appendStringInfo(¶m_str, "%s$%d = ",
+ paramno > 0 ? ", " : "",
+ paramno + 1);
+
+ if (prm->isnull)
+ {
+ appendStringInfoString(¶m_str, "NULL");
+ continue;
+ }
+
+ if (params->hasTextValues)
+ pstring = prm->textValue;
+ else
+ {
+ Oid typoutput;
+ bool typisvarlena;
+
+ if (!OidIsValid(prm->ptype))
+ {
+ appendStringInfoString(¶m_str, "UNKNOWN TYPE");
+ continue;
+ }
+
+ getTypeOutputInfo(prm->ptype, &typoutput, &typisvarlena);
+ pstring = OidOutputFunctionCall(typoutput, prm->value);
+ }
+
+ appendStringInfoCharMacro(¶m_str, '\'');
+ for (p = pstring; *p; p++)
+ {
+ if (*p == '\'') /* double single quotes */
+ appendStringInfoCharMacro(¶m_str, *p);
+ appendStringInfoCharMacro(¶m_str, *p);
+ }
+ appendStringInfoCharMacro(¶m_str, '\'');
+
+ if (!params->hasTextValues)
+ pfree(pstring);
+ }
+
+ return param_str.data;
+}
+
/* --------------------------------
* signal handler routines used in PostgresMain()
@@ -4031,10 +4137,11 @@ PostgresMain(int argc, char *argv[],
EmitErrorReport();
/*
- * Make sure debug_query_string gets reset before we possibly clobber
- * the storage it points at.
+ * Make sure these get reset before we possibly clobber
+ * the storages they point at.
*/
debug_query_string = NULL;
+ current_top_portal = NULL;
/*
* Abort the current transaction in order to recover.
diff --git a/src/backend/utils/error/elog.c b/src/backend/utils/error/elog.c
index 8b4720ef3a..40896a2d09 100644
--- a/src/backend/utils/error/elog.c
+++ b/src/backend/utils/error/elog.c
@@ -76,6 +76,7 @@
#include "tcop/tcopprot.h"
#include "utils/guc.h"
#include "utils/memutils.h"
+#include "utils/portal.h"
#include "utils/ps_status.h"
@@ -344,6 +345,7 @@ errstart(int elevel, const char *filename, int lineno,
{
error_context_stack = NULL;
debug_query_string = NULL;
+ current_top_portal = NULL;
}
}
if (++errordata_stack_depth >= ERRORDATA_STACK_SIZE)
@@ -2788,6 +2790,19 @@ write_csvlog(ErrorData *edata)
if (print_stmt && edata->cursorpos > 0)
appendStringInfo(&buf, "%d", edata->cursorpos);
appendStringInfoChar(&buf, ',');
+ if (print_stmt && log_parameters_on_error &&
+ PortalIsValid(current_top_portal))
+ {
+ char *params;
+
+ params = get_portal_bind_params(current_top_portal->portalParams);
+ if (params != NULL)
+ {
+ appendCSVLiteral(&buf, params);
+ pfree(params);
+ }
+ }
+ appendStringInfoChar(&buf, ',');
/* file error location */
if (Log_error_verbosity >= PGERROR_VERBOSE)
@@ -2944,6 +2959,19 @@ send_message_to_server_log(ErrorData *edata)
appendStringInfoString(&buf, _("STATEMENT: "));
append_with_tabs(&buf, debug_query_string);
appendStringInfoChar(&buf, '\n');
+
+ if (log_parameters_on_error && PortalIsValid(current_top_portal))
+ {
+ char *params;
+
+ params = get_portal_bind_params(current_top_portal->portalParams);
+ if (params != NULL)
+ {
+ log_line_prefix(&buf, edata);
+ appendStringInfo(&buf, _("PARAMETERS: %s\n"), params);
+ pfree(params);
+ }
+ }
}
#ifdef HAVE_SYSLOG
diff --git a/src/backend/utils/misc/guc.c b/src/backend/utils/misc/guc.c
index 90ffd89339..d426272be3 100644
--- a/src/backend/utils/misc/guc.c
+++ b/src/backend/utils/misc/guc.c
@@ -483,6 +483,7 @@ 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;
@@ -1293,6 +1294,15 @@ 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 0fc23e3a61..fccfff3a03 100644
--- a/src/backend/utils/misc/postgresql.conf.sample
+++ b/src/backend/utils/misc/postgresql.conf.sample
@@ -532,6 +532,7 @@
# 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/include/nodes/params.h b/src/include/nodes/params.h
index fd9046619c..316d3a2888 100644
--- a/src/include/nodes/params.h
+++ b/src/include/nodes/params.h
@@ -93,6 +93,7 @@ typedef struct ParamExternData
bool isnull; /* is it NULL? */
uint16 pflags; /* flag bits, see above */
Oid ptype; /* parameter's datatype, or 0 */
+ char *textValue; /* textual representation for debug purposes */
} ParamExternData;
typedef struct ParamListInfoData *ParamListInfo;
@@ -116,6 +117,8 @@ typedef struct ParamListInfoData
ParserSetupHook parserSetup; /* parser setup hook */
void *parserSetupArg;
int numParams; /* nominal/maximum # of Params represented */
+ bool hasTextValues; /* whether textValue for all non-null
+ params is populated */
/*
* params[] may be of length zero if paramFetch is supplied; otherwise it
diff --git a/src/include/tcop/tcopprot.h b/src/include/tcop/tcopprot.h
index ec21f7e45c..ad6517414b 100644
--- a/src/include/tcop/tcopprot.h
+++ b/src/include/tcop/tcopprot.h
@@ -19,6 +19,7 @@
#include "nodes/plannodes.h"
#include "storage/procsignal.h"
#include "utils/guc.h"
+#include "utils/portal.h"
#include "utils/queryenvironment.h"
@@ -27,6 +28,8 @@
extern CommandDest whereToSendOutput;
extern PGDLLIMPORT const char *debug_query_string;
+extern PGDLLIMPORT Portal current_top_portal;
+
extern int max_stack_depth;
extern int PostAuthDelay;
@@ -78,6 +81,7 @@ extern long get_stack_depth_rlimit(void);
extern void ResetUsage(void);
extern void ShowUsage(const char *title);
extern int check_log_duration(char *msec_str, bool was_logged);
+extern char *get_portal_bind_params(ParamListInfo params);
extern void set_debug_options(int debug_flag,
GucContext context, GucSource source);
extern bool set_plan_disabling_options(const char *arg,
diff --git a/src/include/utils/guc.h b/src/include/utils/guc.h
index 6791e0cbc2..57acc28ef9 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;
diff --git a/src/test/README b/src/test/README
index b5ccfc0cf6..22e624d8ba 100644
--- a/src/test/README
+++ b/src/test/README
@@ -12,8 +12,7 @@ authentication/
Tests for authentication
examples/
- Demonstration programs for libpq that double as regression tests via
- "make check"
+ Demonstration programs for libpq that double as regression tests
isolation/
Tests for concurrent behavior at the SQL level
diff --git a/src/test/examples/Makefile b/src/test/examples/Makefile
index a67f456904..0407ca60bc 100644
--- a/src/test/examples/Makefile
+++ b/src/test/examples/Makefile
@@ -14,7 +14,7 @@ override CPPFLAGS := -I$(libpq_srcdir) $(CPPFLAGS)
LDFLAGS_INTERNAL += $(libpq_pgport)
-PROGS = testlibpq testlibpq2 testlibpq3 testlibpq4 testlo testlo64
+PROGS = testlibpq testlibpq2 testlibpq3 testlibpq4 testlibpq5 testlo testlo64
all: $(PROGS)
diff --git a/src/test/examples/testlibpq5.c b/src/test/examples/testlibpq5.c
new file mode 100644
index 0000000000..69b65c512b
--- /dev/null
+++ b/src/test/examples/testlibpq5.c
@@ -0,0 +1,116 @@
+/*
+ * src/test/examples/testlibpq5.c
+ *
+ * testlibpq5.c
+ * Test logging of statement parameters in case of errors.
+ */
+
+#ifdef WIN32
+#include <windows.h>
+#endif
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <string.h>
+#include <sys/types.h>
+#include "libpq-fe.h"
+
+static void
+exit_nicely(PGconn *conn)
+{
+ PQfinish(conn);
+ exit(1);
+}
+
+int
+main(int argc, char **argv)
+{
+ const char *conninfo;
+ PGconn *conn;
+ PGresult *res;
+ const char *paramValues[3];
+ int paramLengths[3];
+ int paramFormats[3];
+ uint32_t binaryIntVal;
+
+ /*
+ * If the user supplies a parameter on the command line, use it as the
+ * conninfo string; otherwise default to setting dbname=postgres and using
+ * environment variables or defaults for all other connection parameters.
+ */
+ if (argc > 1)
+ conninfo = argv[1];
+ else
+ conninfo = "dbname = postgres";
+
+ /* Make a connection to the database */
+ conn = PQconnectdb(conninfo);
+
+ /* Check to see that the backend connection was successfully made */
+ if (PQstatus(conn) != CONNECTION_OK)
+ {
+ fprintf(stderr, "Connection to database failed: %s",
+ PQerrorMessage(conn));
+ exit_nicely(conn);
+ }
+
+ /* Set always-secure search path, so malicious users can't take control. */
+ res = PQexec(conn,
+ "SELECT pg_catalog.set_config('search_path', '', false)");
+ if (PQresultStatus(res) != PGRES_TUPLES_OK)
+ {
+ fprintf(stderr, "SET failed: %s", PQerrorMessage(conn));
+ PQclear(res);
+ exit_nicely(conn);
+ }
+ PQclear(res);
+
+ /*
+ * Transmit parameters in different forms and make a statement fail. User
+ * can then verify the server log.
+ */
+ res = PQexec(conn, "SET log_parameters_on_error = on");
+ if (PQresultStatus(res) != PGRES_COMMAND_OK)
+ {
+ fprintf(stderr, "SET failed: %s", PQerrorMessage(conn));
+ PQclear(res);
+ exit_nicely(conn);
+ }
+ PQclear(res);
+
+ paramValues[0] = (char *) &binaryIntVal;
+ paramLengths[0] = sizeof(binaryIntVal);
+ paramFormats[0] = 1; /* binary */
+ paramValues[1] = "2";
+ paramLengths[1] = strlen(paramValues[1]) + 1;
+ paramFormats[1] = 0; /* text */
+ paramValues[2] = (char *) "everyone's little $$ in \"dollar\"";
+ paramLengths[2] = strlen(paramValues[2]) + 1;
+ paramFormats[2] = 0; /* text */
+ /* divide by zero -- but server won't realize until execution */
+ res = PQexecParams(conn,
+ "SELECT 1 / (random() / 2)::int + $1::int + $2::int, $3::text",
+ 3, /* # params */
+ NULL, /* let the backend deduce param type */
+ paramValues,
+ paramLengths,
+ paramFormats,
+ 1); /* ask for binary results */
+
+ if (PQresultStatus(res) != PGRES_FATAL_ERROR)
+ {
+ fprintf(stderr, "SELECT succeeded but was supposed to fail");
+ PQclear(res);
+ exit_nicely(conn);
+ }
+ PQclear(res);
+ printf("Division by zero expected, got an error message from server: %s\n"
+ "Please make sure it has been logged with bind parameters in server log\n",
+ PQerrorMessage(conn));
+
+ /* close the connection to the database and cleanup */
+ PQfinish(conn);
+
+ return 0;
+}
--
2.17.1
