mirror of
https://github.com/scylladb/scylladb.git
synced 2026-05-30 11:36:54 +00:00
220d6dde17
The test test_fetch_from_system_tables tests Alternator's system-table feature by reading from all system tables. The intention was to confirm we don't crash reading any of them - as they have different schemas and can run into different problems (we had such problems in the initial implementation). The intention was not to read *a lot* from each table - we only make a single "Scan" call on each, to read one page of data. However, the Scan call did not set a Limit, so the single page can get pretty big. This is not normally a problem, but in extremely slow runs - such as when running the debug build on an extremely overcommitted test machine (e.g., issue #7706) reading this large page may take longer than our default timeout. I'll send a separate patch for the timeout issue, but for now, there is really no reason why we need to read a big page. It is good enough to just read 50 rows (with Limit=50). This will still read all the different types and make the test faster. As an example, in the debug run on my laptop, this test spent 2.4 seconds to read the "compaction_history" table before this patch, and only 0.1 seconds after this patch. 2.4 seconds is close to our default timeout (10 seconds), 0.1 is very far. Fixes #7706 Signed-off-by: Nadav Har'El <nyh@scylladb.com> Message-Id: <20201207075112.2548178-1-nyh@scylladb.com>