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578b229718
Previously tables declared WITH OIDS, including a significant fraction of the catalog tables, stored the oid column not as a normal column, but as part of the tuple header. This special column was not shown by default, which was somewhat odd, as it's often (consider e.g. pg_class.oid) one of the more important parts of a row. Neither pg_dump nor COPY included the contents of the oid column by default. The fact that the oid column was not an ordinary column necessitated a significant amount of special case code to support oid columns. That already was painful for the existing, but upcoming work aiming to make table storage pluggable, would have required expanding and duplicating that "specialness" significantly. WITH OIDS has been deprecated since 2005 (commit ff02d0a05280e0). Remove it. Removing includes: - CREATE TABLE and ALTER TABLE syntax for declaring the table to be WITH OIDS has been removed (WITH (oids[ = true]) will error out) - pg_dump does not support dumping tables declared WITH OIDS and will issue a warning when dumping one (and ignore the oid column). - restoring an pg_dump archive with pg_restore will warn when restoring a table with oid contents (and ignore the oid column) - COPY will refuse to load binary dump that includes oids. - pg_upgrade will error out when encountering tables declared WITH OIDS, they have to be altered to remove the oid column first. - Functionality to access the oid of the last inserted row (like plpgsql's RESULT_OID, spi's SPI_lastoid, ...) has been removed. The syntax for declaring a table WITHOUT OIDS (or WITH (oids = false) for CREATE TABLE) is still supported. While that requires a bit of support code, it seems unnecessary to break applications / dumps that do not use oids, and are explicit about not using them. The biggest user of WITH OID columns was postgres' catalog. This commit changes all 'magic' oid columns to be columns that are normally declared and stored. To reduce unnecessary query breakage all the newly added columns are still named 'oid', even if a table's column naming scheme would indicate 'reloid' or such. This obviously requires adapting a lot code, mostly replacing oid access via HeapTupleGetOid() with access to the underlying Form_pg_*->oid column. The bootstrap process now assigns oids for all oid columns in genbki.pl that do not have an explicit value (starting at the largest oid previously used), only oids assigned later by oids will be above FirstBootstrapObjectId. As the oid column now is a normal column the special bootstrap syntax for oids has been removed. Oids are not automatically assigned during insertion anymore, all backend code explicitly assigns oids with GetNewOidWithIndex(). For the rare case that insertions into the catalog via SQL are called for the new pg_nextoid() function can be used (which only works on catalog tables). The fact that oid columns on system tables are now normal columns means that they will be included in the set of columns expanded by * (i.e. SELECT * FROM pg_class will now include the table's oid, previously it did not). It'd not technically be hard to hide oid column by default, but that'd mean confusing behavior would either have to be carried forward forever, or it'd cause breakage down the line. While it's not unlikely that further adjustments are needed, the scope/invasiveness of the patch makes it worthwhile to get merge this now. It's painful to maintain externally, too complicated to commit after the code code freeze, and a dependency of a number of other patches. Catversion bump, for obvious reasons. Author: Andres Freund, with contributions by John Naylor Discussion: https://postgr.es/m/20180930034810.ywp2c7awz7opzcfr@alap3.anarazel.de
62 lines
2.2 KiB
C
62 lines
2.2 KiB
C
/*-------------------------------------------------------------------------
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*
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* genbki.h
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* Required include file for all POSTGRES catalog header files
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*
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* genbki.h defines CATALOG(), BKI_BOOTSTRAP and related macros
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* so that the catalog header files can be read by the C compiler.
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* (These same words are recognized by genbki.pl to build the BKI
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* bootstrap file from these header files.)
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*
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*
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* Portions Copyright (c) 1996-2018, 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/genbki.h
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef GENBKI_H
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#define GENBKI_H
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/* Introduces a catalog's structure definition */
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#define CATALOG(name,oid,oidmacro) typedef struct CppConcat(FormData_,name)
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/* Options that may appear after CATALOG (on the same line) */
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#define BKI_BOOTSTRAP
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#define BKI_SHARED_RELATION
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#define BKI_ROWTYPE_OID(oid,oidmacro)
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#define BKI_SCHEMA_MACRO
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/* Options that may appear after an attribute (on the same line) */
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#define BKI_FORCE_NULL
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#define BKI_FORCE_NOT_NULL
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/* Specifies a default value for a catalog field */
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#define BKI_DEFAULT(value)
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/* Specifies a default value for auto-generated array types */
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#define BKI_ARRAY_DEFAULT(value)
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/* Indicates how to perform name lookups for an OID or OID-array field */
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#define BKI_LOOKUP(catalog)
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/* The following are never defined; they are here only for documentation. */
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/*
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* Variable-length catalog fields (except possibly the first not nullable one)
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* should not be visible in C structures, so they are made invisible by #ifdefs
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* of an undefined symbol. See also MARKNOTNULL in bootstrap.c for how this is
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* handled.
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*/
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#undef CATALOG_VARLEN
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/*
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* There is code in some catalog headers that needs to be visible to clients,
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* but we don't want clients to include the full header because of safety
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* issues with other code in the header. To handle that, surround code that
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* should be visible to clients with "#ifdef EXPOSE_TO_CLIENT_CODE". That
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* instructs genbki.pl to copy the section when generating the corresponding
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* "_d" header, which can be included by both client and backend code.
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*/
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#undef EXPOSE_TO_CLIENT_CODE
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#endif /* GENBKI_H */
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