database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-07-27 12:41:57 +03:00
Code Activity

Clean up manipulations of hash indexes' hasho_flag field.

Browse Source 
Standardize on testing a hash index page's type by doing
	(opaque->hasho_flag & LH_PAGE_TYPE) == LH_xxx_PAGE
Various places were taking shortcuts like
	opaque->hasho_flag & LH_BUCKET_PAGE
which while not actually wrong, is still bad practice because
it encourages use of
	opaque->hasho_flag & LH_UNUSED_PAGE
which *is* wrong (LH_UNUSED_PAGE == 0, so the above is constant false).
hash_xlog.c's hash_mask() contained such an incorrect test.

This also ensures that we mask out the additional flag bits that
hasho_flag has accreted since 9.6.  pgstattuple's pgstat_hash_page(),
for one, was failing to do that and was thus actively broken.

Also fix assorted comments that hadn't been updated to reflect the
extended usage of hasho_flag, and fix some macros that were testing
just "(hasho_flag & bit)" to use the less dangerous, project-approved
form "((hasho_flag & bit) != 0)".

Coverity found the bug in hash_mask(); I noted the one in
pgstat_hash_page() through code reading.
This commit is contained in:
Tom Lane
2017-04-14 17:04:25 -04:00
parent 1dffabed49
commit 2040bb4a0b
6 changed files with 29 additions and 25 deletions
Download Patch File Download Diff File Expand all files Collapse all files

12
contrib/pageinspect/hashfuncs.c
View File

@ -184,7 +184,8 @@ hash_page_type(PG_FUNCTION_ARGS)
bytea *raw_page = PG_GETARG_BYTEA_P(0);
Page page;
HashPageOpaque opaque;
char *type;
int pagetype;
const char *type;
if (!superuser())
ereport(ERROR,
@ -200,13 +201,14 @@ hash_page_type(PG_FUNCTION_ARGS)
opaque = (HashPageOpaque) PageGetSpecialPointer(page);
/* page type (flags) */
if (opaque->hasho_flag & LH_META_PAGE)
pagetype = opaque->hasho_flag & LH_PAGE_TYPE;
if (pagetype == LH_META_PAGE)
type = "metapage";
else if (opaque->hasho_flag & LH_OVERFLOW_PAGE)
else if (pagetype == LH_OVERFLOW_PAGE)
type = "overflow";
else if (opaque->hasho_flag & LH_BUCKET_PAGE)
else if (pagetype == LH_BUCKET_PAGE)
type = "bucket";
else if (opaque->hasho_flag & LH_BITMAP_PAGE)
else if (pagetype == LH_BITMAP_PAGE)
type = "bitmap";
else
type = "unused";