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Because we assume that int64 and double have the same alignment requirement, AIX's default behavior that alignof(double) = 4 while alignof(int64) = 8 is a headache. There are two issues: 1. We align both int8 and float8 tuple columns per ALIGNOF_DOUBLE, which is an ancient choice that can't be undone without breaking pg_upgrade and creating some subtle SQL-level compatibility issues too. However, the cost of that is just some marginal inefficiency in fetching int8 values, which can't be too awful if the platform architects were willing to pay the same costs for fetching float8s. So our decision is to leave that alone. This patch makes our alignment choices the same as they were pre-v17, namely that ALIGNOF_DOUBLE and ALIGNOF_INT64_T are whatever the compiler prefers and then MAXIMUM_ALIGNOF is the larger of the two. (On all supported platforms other than AIX, all three values will be the same.) 2. We need to overlay C structs onto catalog tuples, and int8 fields in those struct declarations may not be aligned to match this rule. In the old branches we had some annoying rules about ordering catalog columns to avoid alignment problems, but nobody wants to resurrect those. However, there's a better answer: make the compiler construe those struct declarations the way we need it to by using the pack(N) pragma. This requires no manual effort to maintain going forward; we only have to insert the pragma into all the catalog *.h files. (As the catalogs stand at this writing, nothing actually changes because we've not moved any affected columns since v16; hence no catversion bump is required. The point of this is to not have to worry about the issue going forward.) We did not have this option when the AIX port was first made. This patch depends on the C99 feature _Pragma(), as well as the pack(N) pragma which dates to somewhere around gcc 4.0, and probably doesn't exist in xlc at all. But now that we've agreed to toss xlc support out the window, there doesn't seem to be a reason not to go this way. In passing, I got rid of LONGALIGN[_DOWN] along with the configure probes for ALIGNOF_LONG. We were not using those anywhere and it seems highly unlikely that we'd do so in future. Instead supply INT64ALIGN[_DOWN], which isn't used either but at least could have a good reason to be used. Discussion: https://postgr.es/m/1127261.1769649624@sss.pgh.pa.us
90 lines
2.7 KiB
C
90 lines
2.7 KiB
C
/*-------------------------------------------------------------------------
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*
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* pg_range.h
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* definition of the "range type" system catalog (pg_range)
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*
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*
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* Portions Copyright (c) 1996-2026, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* src/include/catalog/pg_range.h
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*
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* NOTES
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* The Catalog.pm module reads this file and derives schema
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* information.
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef PG_RANGE_H
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#define PG_RANGE_H
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#include "catalog/genbki.h"
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#include "catalog/pg_range_d.h" /* IWYU pragma: export */
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/* ----------------
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* pg_range definition. cpp turns this into
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* typedef struct FormData_pg_range
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* ----------------
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*/
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BEGIN_CATALOG_STRUCT
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CATALOG(pg_range,3541,RangeRelationId)
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{
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/* OID of owning range type */
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Oid rngtypid BKI_LOOKUP(pg_type);
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/* OID of range's element type (subtype) */
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Oid rngsubtype BKI_LOOKUP(pg_type);
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/* OID of the range's multirange type */
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Oid rngmultitypid BKI_LOOKUP(pg_type);
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/* collation for this range type, or 0 */
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Oid rngcollation BKI_DEFAULT(0) BKI_LOOKUP_OPT(pg_collation);
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/* subtype's btree opclass */
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Oid rngsubopc BKI_LOOKUP(pg_opclass);
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/* range constructor functions */
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regproc rngconstruct2 BKI_LOOKUP(pg_proc);
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regproc rngconstruct3 BKI_LOOKUP(pg_proc);
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/* multirange constructor functions */
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regproc rngmltconstruct0 BKI_LOOKUP(pg_proc);
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regproc rngmltconstruct1 BKI_LOOKUP(pg_proc);
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regproc rngmltconstruct2 BKI_LOOKUP(pg_proc);
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/* canonicalize range, or 0 */
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regproc rngcanonical BKI_LOOKUP_OPT(pg_proc);
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/* subtype difference as a float8, or 0 */
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regproc rngsubdiff BKI_LOOKUP_OPT(pg_proc);
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} FormData_pg_range;
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END_CATALOG_STRUCT
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/* ----------------
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* Form_pg_range corresponds to a pointer to a tuple with
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* the format of pg_range relation.
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* ----------------
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*/
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typedef FormData_pg_range *Form_pg_range;
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DECLARE_UNIQUE_INDEX_PKEY(pg_range_rngtypid_index, 3542, RangeTypidIndexId, pg_range, btree(rngtypid oid_ops));
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DECLARE_UNIQUE_INDEX(pg_range_rngmultitypid_index, 2228, RangeMultirangeTypidIndexId, pg_range, btree(rngmultitypid oid_ops));
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MAKE_SYSCACHE(RANGETYPE, pg_range_rngtypid_index, 4);
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MAKE_SYSCACHE(RANGEMULTIRANGE, pg_range_rngmultitypid_index, 4);
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/*
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* prototypes for functions in pg_range.c
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*/
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extern void RangeCreate(Oid rangeTypeOid, Oid rangeSubType, Oid rangeCollation,
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Oid rangeSubOpclass, RegProcedure rangeCanonical,
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RegProcedure rangeSubDiff, Oid multirangeTypeOid,
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RegProcedure rangeConstruct2, RegProcedure rangeConstruct3,
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RegProcedure mltrngConstruct0, RegProcedure mltrngConstruct1, RegProcedure mltrngConstruct2);
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extern void RangeDelete(Oid rangeTypeOid);
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#endif /* PG_RANGE_H */
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