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The previous scheme had bugs in some corner cases involving tables that had been renamed since a view was made. This could result in dumped views that failed to reload or reloaded incorrectly, as seen in bug #7553 from Lloyd Albin, as well as in some pgsql-hackers discussion back in January. Also, its behavior for printing EXPLAIN plans was sometimes confusing because of willingness to use the same alias for multiple RTEs (it was Ashutosh Bapat's complaint about that aspect that started the January thread). To fix, ensure that each RTE in the query has a unique unqualified alias, by modifying the alias if necessary (we add "_" and digits as needed to create a non-conflicting name). Then we can just print its variables with that alias, avoiding the confusing and bug-prone scheme of sometimes schema-qualifying variable names. In EXPLAIN, it proves to be expedient to take the further step of only assigning such aliases to RTEs that are actually referenced in the query, since the planner has a habit of generating extra RTEs with the same alias in situations such as inheritance-tree expansion. Although this fixes a bug of very long standing, I'm hesitant to back-patch such a noticeable behavioral change. My experiments while creating a regression test convinced me that actually incorrect output (as opposed to confusing output) occurs only in very narrow cases, which is backed up by the lack of previous complaints from the field. So we may be better off living with it in released branches; and in any case it'd be smart to let this ripen awhile in HEAD before we consider back-patching it. |
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.. | ||
aggregatecmds.c | ||
alter.c | ||
analyze.c | ||
async.c | ||
cluster.c | ||
collationcmds.c | ||
comment.c | ||
constraint.c | ||
conversioncmds.c | ||
copy.c | ||
createas.c | ||
dbcommands.c | ||
define.c | ||
discard.c | ||
dropcmds.c | ||
event_trigger.c | ||
explain.c | ||
extension.c | ||
foreigncmds.c | ||
functioncmds.c | ||
indexcmds.c | ||
lockcmds.c | ||
Makefile | ||
opclasscmds.c | ||
operatorcmds.c | ||
portalcmds.c | ||
prepare.c | ||
proclang.c | ||
schemacmds.c | ||
seclabel.c | ||
sequence.c | ||
tablecmds.c | ||
tablespace.c | ||
trigger.c | ||
tsearchcmds.c | ||
typecmds.c | ||
user.c | ||
vacuum.c | ||
vacuumlazy.c | ||
variable.c | ||
view.c |