Add the access_log extension

.github/workflows/build-gpdb.yml

@@ -156,7 +156,8 @@ jobs:
                                "contrib/xml2:installcheck"]
               },
               {"test":"ic-gpcontrib",
-               "make_configs":["gpcontrib/gp_array_agg:installcheck",
+               "make_configs":["gpcontrib/access_log:installcheck",
+                               "gpcontrib/gp_array_agg:installcheck",
                                "gpcontrib/gp_debug_numsegments:installcheck",
                                "gpcontrib/gp_distribution_policy:installcheck",
                                "gpcontrib/gp_error_handling:installcheck",

gpcontrib/Makefile

@@ -12,7 +12,8 @@ include $(top_builddir)/src/Makefile.global
 recurse_targets = ""
 
 ifeq "$(enable_debug_extensions)" "yes"
-	recurse_targets = gp_sparse_vector \
+	recurse_targets = access_log \
+               gp_sparse_vector \
                gp_distribution_policy \
                gp_parallel_retrieve_cursor \
                gp_internal_tools \
@@ -30,7 +31,8 @@ ifeq "$(enable_debug_extensions)" "yes"
                gp_interconnect_stats \
                temp_tables_stat
 else
-	recurse_targets = gp_sparse_vector \
+	recurse_targets = access_log \
+               gp_sparse_vector \
                gp_distribution_policy \
                gp_parallel_retrieve_cursor \
                gp_internal_tools \
@@ -130,6 +132,7 @@ distclean:
 	if [ "${enable_orafce}" = "yes" ]; then $(MAKE) -C orafce NO_PGXS=true distclean; fi
 
 installcheck:
+	$(MAKE) -C access_log installcheck
 	$(MAKE) -C gp_internal_tools installcheck
 	$(MAKE) -C gp_array_agg installcheck
 	$(MAKE) -C gp_aux_catalog installcheck

gpcontrib/access_log/Makefile

@@ -0,0 +1,17 @@
+# gpcontrib/access_log/Makefile
+
+MODULE_big = access_log
+OBJS = access_log.o
+
+REGRESS = access_log
+
+ifdef USE_PGXS
+PG_CONFIG = pg_config
+PGXS := $(shell $(PG_CONFIG) --pgxs)
+include $(PGXS)
+else
+subdir = gpcontrib/access_log
+top_builddir = ../..
+include $(top_builddir)/src/Makefile.global
+include $(top_srcdir)/contrib/contrib-global.mk
+endif

gpcontrib/access_log/README.md

@@ -0,0 +1,12 @@
+# access_log
+
+The extension logs when and which user initializes Seq Scan on which partition
+or table. The log file name is pg_log/access.log. To activate the extension you
+can use the shared_preload_libraries GUC or the LOAD command.
+
+If you want to register Seq Scans on segments only you should load access_log
+on segments and don't load on master:
+
+```
+gpconfig -c shared_preload_libraries -v 'access_log' -m ''
+```

gpcontrib/access_log/access_log.c

@@ -0,0 +1,91 @@
+#include "postgres.h"
+
+#include "catalog/pg_namespace.h"
+#include "executor/nodeSeqscan.h"
+#include "libpq/auth.h"
+#include "utils/syscache.h"
+
+
+PG_MODULE_MAGIC;
+
+#define LOG_FILE_NAME "pg_log/access.log"
+
+void _PG_init(void);
+
+
+static init_scan_hook_type next_init_scan_hook = NULL;
+
+static void
+write_to_log(const char* str)
+{
+	/*
+	 * Synchronization is not necessary because `man write` says:
+	 * "If the file was open(2)ed with O_APPEND, the file offset is first set to
+	 * the end of the file before writing. The adjustment of the file offset and
+	 * the write operation are performed as an atomic step."
+	 */
+	int f = open(LOG_FILE_NAME, O_WRONLY | O_APPEND | O_CREAT, S_IRUSR | S_IWUSR);
+	if (f < 0 )
+	{
+		ereport(WARNING, (errcode_for_file_access(),
+				errmsg("could not open file " LOG_FILE_NAME)));
+		return;
+	}
+	write(f, str, strlen(str));
+	close(f);
+}
+
+static void
+access_log_init_scan_hook(Relation currentRelation)
+{
+	char		buf[512];
+	HeapTuple	tp;
+	struct timeval	tv;
+
+	gettimeofday(&tv, NULL);
+	pg_strftime(buf, sizeof(buf),
+			"%Y-%m-%d %H:%M:%S        %Z,",
+			pg_localtime((pg_time_t*)&tv.tv_sec, log_timezone));
+
+	/* paste milliseconds into place */
+	sprintf(buf + 19, ".%06d", (int) (tv.tv_usec));
+	/* restore space which has been rewritten by sprintf with \0 */
+	buf[19 + 1 + 6] = ' ';
+
+	if (MyProcPort != NULL && MyProcPort->user_name != NULL)
+		strlcat(buf, MyProcPort->user_name, sizeof(buf));
+	strlcat(buf, ",", sizeof(buf));
+
+	tp = SearchSysCache1(NAMESPACEOID,
+					ObjectIdGetDatum(currentRelation->rd_rel->relnamespace));
+	if (HeapTupleIsValid(tp))
+	{
+		Form_pg_namespace nsptup = (Form_pg_namespace) GETSTRUCT(tp);
+		strlcat(buf, NameStr(nsptup->nspname), sizeof(buf));
+		strlcat(buf, ".", sizeof(buf));
+		ReleaseSysCache(tp);
+	}
+
+	strlcat(buf, NameStr(currentRelation->rd_rel->relname), sizeof(buf));
+	strlcat(buf, "\n", sizeof(buf));
+
+	write_to_log(buf);
+
+	if (next_init_scan_hook)
+		next_init_scan_hook(currentRelation);
+}
+
+void
+_PG_init(void)
+{
+	/* Be sure we do initialization only once */
+	static bool inited = false;
+
+	if (inited)
+		return;
+
+	next_init_scan_hook = init_scan_hook;
+	init_scan_hook = access_log_init_scan_hook;
+
+	inited = true;
+}