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Use wrappers of PG_DETOAST_DATUM_PACKED() more.

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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.
This commit is contained in:
Noah Misch
2017-03-12 19:35:34 -04:00
parent 9d7726c2ba
commit 3a0d473192
59 changed files with 521 additions and 529 deletions
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17
contrib/pg_trgm/trgm_gist.c
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@ -100,9 +100,9 @@ gtrgm_compress(PG_FUNCTION_ARGS)
if (entry->leafkey)
{ /* trgm */
TRGM *res;
text *val = DatumGetTextP(entry->key);
text *val = DatumGetTextPP(entry->key);
res = generate_trgm(VARDATA(val), VARSIZE(val) - VARHDRSZ);
res = generate_trgm(VARDATA_ANY(val), VARSIZE_ANY_EXHDR(val));
retval = (GISTENTRY *) palloc(sizeof(GISTENTRY));
gistentryinit(*retval, PointerGetDatum(res),
entry->rel, entry->page,
@ -142,7 +142,7 @@ gtrgm_decompress(PG_FUNCTION_ARGS)
GISTENTRY *retval;
text *key;
key = DatumGetTextP(entry->key);
key = DatumGetTextPP(entry->key);
if (key != (text *) DatumGetPointer(entry->key))
{
@ -200,11 +200,12 @@ gtrgm_consistent(PG_FUNCTION_ARGS)
* depends on strategy.
*
* The cached structure is a single palloc chunk containing the
* gtrgm_consistent_cache header, then the input query (starting at a
* MAXALIGN boundary), then the TRGM value (also starting at a MAXALIGN
* boundary). However we don't try to include the regex graph (if any) in
* that struct. (XXX currently, this approach can leak regex graphs
* across index rescans. Not clear if that's worth fixing.)
* gtrgm_consistent_cache header, then the input query (4-byte length
* word, uncompressed, starting at a MAXALIGN boundary), then the TRGM
* value (also starting at a MAXALIGN boundary). However we don't try to
* include the regex graph (if any) in that struct. (XXX currently, this
* approach can leak regex graphs across index rescans. Not clear if
* that's worth fixing.)
*/
cache = (gtrgm_consistent_cache *) fcinfo->flinfo->fn_extra;
if (cache == NULL ||