diff options
| author | Peter Eisentraut <peter@eisentraut.org> | 2020-11-25 15:30:18 +0100 |
|---|---|---|
| committer | Peter Eisentraut <peter@eisentraut.org> | 2020-11-25 15:30:18 +0100 |
| commit | f73999262ed6c40d9a7c3d7cccec7143d4d15287 (patch) | |
| tree | b8f9d03bd2943346d96e7a70fa33816502e1030b /contrib/tablefunc/tablefunc.c | |
| parent | 2fbd786c3446b1bc90f396d3fa5f4614b0a57d89 (diff) | |
tablefunc: Reject negative number of tuples passed to normal_rand()
The function converted the first argument i.e. the number of tuples to
return into an unsigned integer which turns out to be huge number when
a negative value is passed. This causes the function to take much
longer time to execute. Instead, reject a negative value.
(If someone really wants to generate many more result rows, they
should consider adding a bigint or numeric variant.)
While at it, improve SQL test to test the number of tuples returned by
this function.
Author: Ashutosh Bapat <ashutosh.bapat@2ndquadrant.com>
Discussion: https://www.postgresql.org/message-id/CAG-ACPW3PUUmSnM6cLa9Rw4BEC5cEMKjX8Gogc8gvQcT3cYA1A@mail.gmail.com
Diffstat (limited to 'contrib/tablefunc/tablefunc.c')
| -rw-r--r-- | contrib/tablefunc/tablefunc.c | 9 |
1 files changed, 8 insertions, 1 deletions
diff --git a/contrib/tablefunc/tablefunc.c b/contrib/tablefunc/tablefunc.c index 02f02eab574..85986ec24ad 100644 --- a/contrib/tablefunc/tablefunc.c +++ b/contrib/tablefunc/tablefunc.c @@ -184,6 +184,8 @@ normal_rand(PG_FUNCTION_ARGS) /* stuff done only on the first call of the function */ if (SRF_IS_FIRSTCALL()) { + int32 num_tuples; + /* create a function context for cross-call persistence */ funcctx = SRF_FIRSTCALL_INIT(); @@ -193,7 +195,12 @@ normal_rand(PG_FUNCTION_ARGS) oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx); /* total number of tuples to be returned */ - funcctx->max_calls = PG_GETARG_UINT32(0); + num_tuples = PG_GETARG_INT32(0); + if (num_tuples < 0) + ereport(ERROR, + (errcode(ERRCODE_INVALID_PARAMETER_VALUE), + errmsg("number of rows cannot be negative"))); + funcctx->max_calls = num_tuples; /* allocate memory for user context */ fctx = (normal_rand_fctx *) palloc(sizeof(normal_rand_fctx)); |