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Improve hash_create()'s API for some added robustness.
Invent a new flag bit HASH_STRINGS to specify C-string hashing, which
was formerly the default; and add assertions insisting that exactly
one of the bits HASH_STRINGS, HASH_BLOBS, and HASH_FUNCTION be set.
This is in hopes of preventing recurrences of the type of oversight
fixed in commit a1b8aa1e4
(i.e., mistakenly omitting HASH_BLOBS).
Also, when HASH_STRINGS is specified, insist that the keysize be
more than 8 bytes. This is a heuristic, but it should catch
accidental use of HASH_STRINGS for integer or pointer keys.
(Nearly all existing use-cases set the keysize to NAMEDATALEN or
more, so there's little reason to think this restriction should
be problematic.)
Tweak hash_create() to insist that the HASH_ELEM flag be set, and
remove the defaults it had for keysize and entrysize. Since those
defaults were undocumented and basically useless, no callers
omitted HASH_ELEM anyway.
Also, remove memset's zeroing the HASHCTL parameter struct from
those callers that had one. This has never been really necessary,
and while it wasn't a bad coding convention it was confusing that
some callers did it and some did not. We might as well save a few
cycles by standardizing on "not".
Also improve the documentation for hash_create().
In passing, improve reinit.c's usage of a hash table by storing
the key as a binary Oid rather than a string; and, since that's
a temporary hash table, allocate it in CurrentMemoryContext for
neatness.
Discussion: https://postgr.es/m/590625.1607878171@sss.pgh.pa.us
This commit is contained in:
3
src/backend/utils/cache/ts_cache.c
vendored
3
src/backend/utils/cache/ts_cache.c
vendored
@ -117,7 +117,6 @@ lookup_ts_parser_cache(Oid prsId)
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/* First time through: initialize the hash table */
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HASHCTL ctl;
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MemSet(&ctl, 0, sizeof(ctl));
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ctl.keysize = sizeof(Oid);
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ctl.entrysize = sizeof(TSParserCacheEntry);
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TSParserCacheHash = hash_create("Tsearch parser cache", 4,
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@ -215,7 +214,6 @@ lookup_ts_dictionary_cache(Oid dictId)
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/* First time through: initialize the hash table */
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HASHCTL ctl;
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MemSet(&ctl, 0, sizeof(ctl));
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ctl.keysize = sizeof(Oid);
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ctl.entrysize = sizeof(TSDictionaryCacheEntry);
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TSDictionaryCacheHash = hash_create("Tsearch dictionary cache", 8,
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@ -365,7 +363,6 @@ init_ts_config_cache(void)
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{
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HASHCTL ctl;
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MemSet(&ctl, 0, sizeof(ctl));
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ctl.keysize = sizeof(Oid);
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ctl.entrysize = sizeof(TSConfigCacheEntry);
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TSConfigCacheHash = hash_create("Tsearch configuration cache", 16,
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