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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 |
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| .. | ||
| po | ||
| .gitignore | ||
| c_keywords.c | ||
| check_rules.pl | ||
| descriptor.c | ||
| ecpg_keywords.c | ||
| ecpg.addons | ||
| ecpg.c | ||
| ecpg.header | ||
| ecpg.tokens | ||
| ecpg.trailer | ||
| ecpg.type | ||
| extern.h | ||
| keywords.c | ||
| Makefile | ||
| nls.mk | ||
| output.c | ||
| parse.pl | ||
| parser.c | ||
| pgc.l | ||
| README.parser | ||
| type.c | ||
| type.h | ||
| variable.c | ||
ECPG modifies and extends the core grammar in a way that
1) every token in ECPG is <str> type. New tokens are
defined in ecpg.tokens, types are defined in ecpg.type
2) most tokens from the core grammar are simply converted
to literals concatenated together to form the SQL string
passed to the server, this is done by parse.pl.
3) some rules need side-effects, actions are either added
or completely overridden (compared to the basic token
concatenation) for them, these are defined in ecpg.addons,
the rules for ecpg.addons are explained below.
4) new grammar rules are needed for ECPG metacommands.
These are in ecpg.trailer.
5) ecpg.header contains common functions, etc. used by
actions for grammar rules.
In "ecpg.addons", every modified rule follows this pattern:
ECPG: dumpedtokens postfix
where "dumpedtokens" is simply tokens from core gram.y's
rules concatenated together. e.g. if gram.y has this:
ruleA: tokenA tokenB tokenC {...}
then "dumpedtokens" is "ruleAtokenAtokenBtokenC".
"postfix" above can be:
a) "block" - the automatic rule created by parse.pl is completely
overridden, the code block has to be written completely as
it were in a plain bison grammar
b) "rule" - the automatic rule is extended on, so new syntaxes
are accepted for "ruleA". E.g.:
ECPG: ruleAtokenAtokenBtokenC rule
| tokenD tokenE { action_code; }
...
It will be substituted with:
ruleA: <original syntax forms and actions up to and including
"tokenA tokenB tokenC">
| tokenD tokenE { action_code; }
...
c) "addon" - the automatic action for the rule (SQL syntax constructed
from the tokens concatenated together) is prepended with a new
action code part. This code part is written as is's already inside
the { ... }
Multiple "addon" or "block" lines may appear together with the
new code block if the code block is common for those rules.