Re: Statistics Import and Export

On Tue, Jan 21, 2025 at 2:43 PM Corey Huinker <corey(dot)huinker(at)gmail(dot)com> wrote:
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>
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> On Mon, Jan 20, 2025 at 10:59 PM Corey Huinker <corey(dot)huinker(at)gmail(dot)com> wrote:
>>>
>>> Are you saying that there is a path for a partitioned index to have
>>> stats today? If so, we can just follow that locking protocol. If not,
>>> I'm concerned about trying to define the locking protocol for doing so
>>> as a side-effect of this work.
>>
>>
>> A quick test on v17 indicates that, no, there is no path for a partitioned index to have stats of its own, so I'm fine with removing RELKIND_PARTITIONED_INDEX from the allowable relkinds. The partitions of the partitioned index have stats but the umbrella index does not.
>>
>>>
>>> Wouldn't it be easy enough to issue a WARNING and skip it?
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>>
>> Sure.
>>
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> So this is the next iteration - it rejects setting stats on partitioned indexes entirely, and it does all the ACL checks against the underlying relation instead of the indexrel. The only oddity is that if a user calls a statistics setting function on some_index of some_table, and they do not have permission to modify stats on some_table, the error message they get reflects the lack of permission on some_table, not the some_index that was invoked. That may be initially surprising, but it actually is more helpful because the permissions that need to change are on the table not the index.

/*
* For indexes, we follow what do_analyze_rel() does so as to avoid any
* deadlocks with analyze/vacuum, which is to take out a
* ShareUpdateExclusive on table/matview first and only after that take
* a a AccessShareLock on the index itself.
*/
there are two "a a".

#include "access/relation.h"
+#include "c.h"
+#include "catalog/pg_class_d.h"
#include "catalog/pg_database.h"
+#include "catalog/index.h"
+#include "storage/lockdefs.h"
+#include "storage/lmgr.h"
#include "utils/acl.h"
+#include "utils/lsyscache.h"
#include "utils/rel.h"
+#include "utils/syscache.h"

+#include "c.h", no need. since we have "postgres.h"
+#include "storage/lockdefs.h" no need. because #include
"storage/lmgr.h" already have it.
+#include "utils/syscache.h" no need. because get_rel_relkind is in
``#include "utils/lsyscache.h"``

in pg_class.h we have
#include "catalog/pg_class_d.h" /* IWYU pragma: export */
if i read
https://github.com/include-what-you-use/include-what-you-use/blob/master/docs/IWYUPragmas.md#iwyu-pragma-export
correctly.
here
+#include "catalog/pg_class_d.h"
should be
+#include "catalog/pg_class.h"