With this change array fields are populated from json(b) arrays, and
composite fields are populated from json(b) objects.
Along the way, some significant code refactoring is done to remove
redundancy in the way to populate_record[_set] and to_record[_set]
functions operate, and some significant efficiency gains are made by
caching tuple descriptors.
Nikita Glukhov, edited some by me.
Reviewed by Aleksander Alekseev and Tom Lane.
This makes almost all core code follow the policy introduced in the
previous commit. Specific decisions:
- Text search support functions with char* and length arguments, such as
prsstart and lexize, may receive unaligned strings. I doubt
maintainers of non-core text search code will notice.
- Use plain VARDATA() on values detoasted or synthesized earlier in the
same function. Use VARDATA_ANY() on varlenas sourced outside the
function, even if they happen to always have four-byte headers. As an
exception, retain the universal practice of using VARDATA() on return
values of SendFunctionCall().
- Retain PG_GETARG_BYTEA_P() in pageinspect. (Page images are too large
for a one-byte header, so this misses no optimization.) Sites that do
not call get_page_from_raw() typically need the four-byte alignment.
- For now, do not change btree_gist. Its use of four-byte headers in
memory is partly entangled with storage of 4-byte headers inside
GBT_VARKEY, on disk.
- For now, do not change gtrgm_consistent() or gtrgm_distance(). They
incorporate the varlena header into a cache, and there are multiple
credible implementation strategies to consider.
In functions that issue a deconstruct_array() call, consistently use
plain VARSIZE()/VARDATA() on the array elements. Prior practice was
divided between those and VARSIZE_ANY_EXHDR()/VARDATA_ANY().
This improves readability a bit and may make future improvements easier.
In passing, make sure that the JB_ROOT_IS_XXX macros deliver boolean (0/1)
results; the previous coding was a bug hazard, though no actual bugs are
known.
Nikita Glukhov, extended a bit by me
Discussion: https://postgr.es/m/9e21a39c-c1d7-b9b5-44a0-c5345a5029f6@postgrespro.ru
Project style is to put things in this order, for the good and sufficient
reason that you often need the typedefs in the function declarations.
There already was one function declaration that needed a typedef, which
was randomly placed away from all the other static function declarations
in consequence. And the submitted patch for better json_populate_record
functionality jumped through even more hoops in order to preserve this
bad idea.
This patch only moves lines from point A to point B, no other changes.
This makes it possible to delete multiple keys from a jsonb value by
passing in an array of text values, which makes the operaiton much
faster than individually deleting the keys (which would require copying
the jsonb structure over and over again.
Reviewed by Dmitry Dolgov and Michael Paquier
Commit 0b62fd036 did a fairly sloppy job of refactoring setPath()
to support jsonb_insert() along with jsonb_set(). In its defense,
though, there was no regression test case exercising the case of
replacing an existing element in a jsonb array.
Per bug #14366 from Peng Sun. Back-patch to 9.6 where bug was introduced.
Report: <20161012065349.1412.47858@wrigleys.postgresql.org>
I found that half a dozen (nearly 5%) of our AllocSetContextCreate calls
had typos in the context-sizing parameters. While none of these led to
especially significant problems, they did create minor inefficiencies,
and it's now clear that expecting people to copy-and-paste those calls
accurately is not a great idea. Let's reduce the risk of future errors
by introducing single macros that encapsulate the common use-cases.
Three such macros are enough to cover all but two special-purpose contexts;
those two calls can be left as-is, I think.
While this patch doesn't in itself improve matters for third-party
extensions, it doesn't break anything for them either, and they can
gradually adopt the simplified notation over time.
In passing, change TopMemoryContext to use the default allocation
parameters. Formerly it could only be extended 8K at a time. That was
probably reasonable when this code was written; but nowadays we create
many more contexts than we did then, so that it's not unusual to have a
couple hundred K in TopMemoryContext, even without considering various
dubious code that sticks other things there. There seems no good reason
not to let it use growing blocks like most other contexts.
Back-patch to 9.6, mostly because that's still close enough to HEAD that
it's easy to do so, and keeping the branches in sync can be expected to
avoid some future back-patching pain. The bugs fixed by these changes
don't seem to be significant enough to justify fixing them further back.
Discussion: <21072.1472321324@sss.pgh.pa.us>
It inserts a new value into an jsonb array at arbitrary position or
a new key to jsonb object.
Author: Dmitry Dolgov
Reviewers: Petr Jelinek, Vitaly Burovoy, Andrew Dunstan
User-facing (even tested by regression tests) error conditions were thrown
with elog(), hence had wrong SQLSTATE and were untranslatable. And the
error message texts weren't up to project style, either.
jsonb_set() could produce wrong answers or incorrect error reports, or in
the worst case even crash, when trying to convert a path-array element into
an integer for use as an array subscript. Per report from Vitaly Burovoy.
Back-patch to 9.5 where the faulty code was introduced (in commit
c6947010ce).
Michael Paquier
A thinko concerning nesting depth caused json_to_record() to produce bogus
output if a field of its input object contained a sub-object with a field
name matching one of the requested output column names. Per bug #13996
from Johann Visagie.
I added a regression test case based on his example, plus parallel tests
for json_to_recordset, jsonb_to_record, jsonb_to_recordset. The latter
three do not exhibit the same bug (which suggests that we may be missing
some opportunities to share code...) but testing seems like a good idea
in any case.
Back-patch to 9.4 where these functions were introduced.
Many functions stored JsonbIteratorToken values in variables of other
integer types. Also, standardize order relative to other declarations.
Expect compilers to generate the same code before and after this change.
Sufficiently-deep recursion heretofore elicited a SIGSEGV. If an
application constructs PostgreSQL json or jsonb values from arbitrary
user input, application users could have exploited this to terminate all
active database connections. That applies to 9.3, where the json parser
adopted recursive descent, and later versions. Only row_to_json() and
array_to_json() were at risk in 9.2, both in a non-security capacity.
Back-patch to 9.2, where the json type was introduced.
Oskari Saarenmaa, reviewed by Michael Paquier.
Security: CVE-2015-5289
Null path elements and, where the object is an array, invalid integer
elements now cause an error.
Incorrect behaviour noted by Thom Brown, patch from Dmitry Dolgov.
Backpatch to 9.5 where jsonb_set was introduced
To prevent perverse results, we now only return the other operand if
it's not scalar, and if both operands are of the same kind (array or
object).
Original bug complaint and patch from Oskari Saarenmaa, extended by me
to cover the cases of different kinds of jsonb.
Backpatch to 9.5 where jsonb_concat was introduced.
The previous code resulted in memory access beyond the path bounds. The
cure is to move it into a code branch that checks the value of lex_level
is within the correct bounds.
Bug reported and diagnosed by Piotr Stefaniak.
Previously, there was an inconsistency across json/jsonb operators that
operate on datums containing JSON arrays -- only some operators
supported negative array count-from-the-end subscripting. Specifically,
only a new-to-9.5 jsonb deletion operator had support (the new "jsonb -
integer" operator). This inconsistency seemed likely to be
counter-intuitive to users. To fix, allow all places where the user can
supply an integer subscript to accept a negative subscript value,
including path-orientated operators and functions, as well as other
extraction operators. This will need to be called out as an
incompatibility in the 9.5 release notes, since it's possible that users
are relying on certain established extraction operators changed here
yielding NULL in the event of a negative subscript.
For the json type, this requires adding a way of cheaply getting the
total JSON array element count ahead of time when parsing arrays with a
negative subscript involved, necessitating an ad-hoc lex and parse.
This is followed by a "conversion" from a negative subscript to its
equivalent positive-wise value using the count. From there on, it's as
if a positive-wise value was originally provided.
Note that there is still a minor inconsistency here across jsonb
deletion operators. Unlike the aforementioned new "-" deletion operator
that accepts an integer on its right hand side, the new "#-" path
orientated deletion variant does not throw an error when it appears like
an array subscript (input that could be recognized by as an integer
literal) is being used on an object, which is wrong-headed. The reason
for not being stricter is that it could be the case that an object pair
happens to have a key value that looks like an integer; in general,
these two possibilities are impossible to differentiate with rhs path
text[] argument elements. However, we still don't allow the "#-"
path-orientated deletion operator to perform array-style subscripting.
Rather, we just return the original left operand value in the event of a
negative subscript (which seems analogous to how the established
"jsonb/json #> text[]" path-orientated operator may yield NULL in the
event of an invalid subscript).
In passing, make SetArrayPath() stricter about not accepting cases where
there is trailing non-numeric garbage bytes rather than a clean NUL
byte. This means, for example, that strings like "10e10" are now not
accepted as an array subscript of 10 by some new-to-9.5 path-orientated
jsonb operators (e.g. the new #- operator). Finally, remove dead code
for jsonb subscript deletion; arguably, this should have been done in
commit b81c7b409.
Peter Geoghegan and Andrew Dunstan
jsonb_set() and other clients of the setPathArray() utility function
could get spurious results when an array integer subscript is provided
that is not within the range of int.
To fix, ensure that the value returned by strtol() within setPathArray()
is within the range of int; when it isn't, assume an invalid input in
line with existing, similar cases. The path-orientated operators that
appeared in PostgreSQL 9.3 and 9.4 do not call setPathArray(), and
already independently take this precaution, so no change there.
Peter Geoghegan
Supporting deletion of JSON pairs within jsonb objects using an
array-style integer subscript allowed for surprising outcomes. This was
mostly due to the implementation-defined ordering of pairs within
objects for jsonb.
It also seems desirable to make jsonb integer subscript deletion
consistent with the 9.4 era general purpose integer subscripting
operator for jsonb (although that operator returns NULL when an object
is encountered, while we prefer here to throw an error).
Peter Geoghegan, following discussion on -hackers.
The function is given a fourth parameter, which defaults to true. When
this parameter is true, if the last element of the path is missing
in the original json, jsonb_set creates it in the result and assigns it
the new value. If it is false then the function does nothing unless all
elements of the path are present, including the last.
Based on some original code from Dmitry Dolgov, heavily modified by me.
Catalog version bumped.
Some of this is made possible by commit
9b74f32cdb which lets pushJsonbValue
handle binary Jsonb values, meaning that clients no longer have to, and
some is just doing things in simpler and more straightforward ways.
These operations now error out if attempted on scalars, and simply
return the input if attempted on empty arrays or objects. Along the way
we remove the unnecessary cloning of the input when it's known to be
unchanged. Regression tests covering these cases are added.
jsonb_pretty(jsonb) produces nicely indented json output.
jsonb || jsonb concatenates two jsonb values.
jsonb - text removes a key and its associated value from the json
jsonb - int removes the designated array element
jsonb - text[] removes a key and associated value or array element at
the designated path
jsonb_replace(jsonb,text[],jsonb) replaces the array element designated
by the path or the value associated with the key designated by the path
with the given value.
Original work by Dmitry Dolgov, adapted and reworked for PostgreSQL core
by Andrew Dunstan, reviewed and tidied up by Petr Jelinek.
The first bug is not releasing a tupdesc when doing an early return out
of the function. The second bug is a logic error in choosing when to do
an early return if given an empty jsonb object.
Bug reports from Pavel Stehule and Tom Lane respectively.
Backpatch to 9.4 where these were introduced.
Mostly these issues concern the non-use of function results. These
have been changed to use (void) pushJsonbValue(...) instead of assigning
the result to a variable that gets overwritten before it is used.
There is a larger issue that we should possibly examine the API for
pushJsonbValue(), so that instead of returning a value it modifies a
state argument. The current idiom is rather clumsy. However, changing
that requires quite a bit more work, so this change should do for the
moment.
The functions remove object fields, including in nested objects, that
have null as a value. In certain cases this can lead to considerably
smaller datums, with no loss of semantic information.
Andrew Dunstan, reviewed by Pavel Stehule.
Cause the path extraction operators to return their lefthand input,
not NULL, if the path array has no elements. This seems more consistent
since the case ought to correspond to applying the simple extraction
operator (->) zero times.
Cause other corner cases in field/element/path extraction to return NULL
rather than failing. This behavior is arguably more useful than throwing
an error, since it allows an expression index using these operators to be
built even when not all values in the column are suitable for the
extraction being indexed. Moreover, we already had multiple
inconsistencies between the path extraction operators and the simple
extraction operators, as well as inconsistencies between the JSON and
JSONB code paths. Adopt a uniform rule of returning NULL rather than
throwing an error when the JSON input does not have a structure that
permits the request to be satisfied.
Back-patch to 9.4. Update the release notes to list this as a behavior
change since 9.3.
jsonb's #> operator segfaulted (dereferencing a null pointer) if the RHS
was a zero-length array, as reported in bug #11207 from Justin Van Winkle.
json's #> operator returns NULL in such cases, so for the moment let's
make jsonb act likewise.
Also add a bunch of regression test queries memorializing the -> and #>
operators' behavior for this and other corner cases.
There is a good argument for changing some of these behaviors, as they
are not very consistent with each other, and throwing an error isn't
necessarily a desirable behavior for operators that are likely to be
used in indexes. However, everybody can agree that a core dump is the
Wrong Thing, and we need test cases even if we decide to change their
expected output later.
The "false" case was really quite useless since all it did was to throw
an error; a definition not helped in the least by making it the default.
Instead let's just have the "true" case, which emits nested objects and
arrays in JSON syntax. We might later want to provide the ability to
emit sub-objects in Postgres record or array syntax, but we'd be best off
to drive that off a check of the target field datatype, not a separate
argument.
For the functions newly added in 9.4, we can just remove the flag arguments
outright. We can't do that for json_populate_record[set], which already
existed in 9.3, but we can ignore the argument and always behave as if it
were "true". It helps that the flag arguments were optional and not
documented in any useful fashion anyway.
I noticed that the functions in jsonfuncs.c sometimes printed error
messages that claimed I'd called some other function. Investigation showed
that this was from repurposing code into "worker" functions without taking
much care as to whether it would mention the right SQL-level function if it
threw an error. Moreover, there was a weird mismash of messages that
contained a fixed function name, messages that used %s for a function name,
and messages that constructed a function name out of spare parts, like
"json%s_populate_record" (which, quite aside from being ugly as sin, wasn't
even sufficient to cover all the cases). This would put an undue burden on
our long-suffering translators. Standardize on inserting the SQL function
name with %s so as to reduce the number of translatable strings, and pass
function names around as needed to make sure we can report the right one.
Fix up some gratuitous variations in wording, too.
Bruce Momjian
Andrew Dunstan
Noah Misch
Tom Lane
Magnus Hagander
Peter Eisentraut
Robert Haas
Teodor Sigaev
Heikki Linnakangas