Thread: pgsql: Short-circuit slice requests that are for more than the object's
Short-circuit slice requests that are for more than the object's size. substring(), and perhaps other callers, isn't careful to pass a slice length that is no more than the datum's true size. Since toast_decompress_datum_slice's children will palloc the requested slice length, this can waste memory. Also, close study of the liblz4 documentation suggests that it is dependent on the caller to not ask for more than the correct amount of decompressed data; this squares with observed misbehavior with liblz4 1.8.3. Avoid these problems by switching to the normal full-decompression code path if the slice request is >= datum's decompressed size. Tom Lane and Dilip Kumar Discussion: https://postgr.es/m/507597.1616370729@sss.pgh.pa.us Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/063dd37ebc7644e8db6419565b50dca019e69e86 Modified Files -------------- src/backend/access/common/detoast.c | 11 +++++++++++ src/include/access/toast_internals.h | 2 ++ 2 files changed, 13 insertions(+)