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Developer's Report: QA Stress Testing & Tools Development
August/September 2013

  • Check CORE-3013 A data source for JOIN that is result of aggregating must be used only one time: Improvement works correctly
  • Regress check CORE-3137 (Partial rollback is possible for a selectable procedure modifying data): works OK, no regression found
  • Regress check CORE-3312 (Sub-optimal join plan when the slave table depends on the master one via the OR predicate): works OK, no regression found
  • Regress check CORE-3340 (Error in autonomous transaction with empty exception handler: can insert duplicate values into PK/UK column (leads to unrestorable backup): works OK, no regression found
  • Comparison of INSERT performance in GTTs (on commit delete | preserve rows) 2.5 vs 3.0: FB 3.0 loses, ratio ~ 5/6
  • Validation of 'true SMP support for Superserver' in Fb3.0 (run 10 isql, each count rows from big data source; watch for load volumes of CPU in `top` utility): Confirmed, all CPU cores are loaded
  • Regress check whether *all* bitmaps are used for each separate index when search condition is like: WHERE field_a = … and field_b starting with … and field_c starting with … (all fields: _a, _b, _c - have indexes); works OK, no regression found
  • Comparison of JOIN performance, data sources: 10 rows and 10E+07 rows (indexed) 2.5 vs 3.0: FB 3.0 was better: 5.5 vs 8.4 in earlier tests but now it is NOT true! Time is equal)
  • Check issue about unnecessary join when condition contains expression that similar to be resolved by compiler as FALSE (like join on 1=0) Fb 3.0: Poor. Firebird still included table that should not ever be processed in plan and under some conditions fetches from that table
  • Compare memory usage on simple join of two data sources, 3.0 vs 2.5: discovered minor bug in mon$memory_usage output; created CORE-4159
  • Check new feature of 3.0: int column generated by default as identity: Troubles when insert by non-privileged user (no usage rights for `rdb$1`); created CORE-4161
  • Compare performance of insex scan vs natural scan, in case of very bad index selectivity (almost 1) 2.5 vs 3.0     3.0 wins!
  • Check performance of simple joins (“count lucky tickets”) and sort that occurs in union DISTINCT (the same task) 2.5 vs 3.0; see also: CORE-4165 (dimitr: Replace the hierarchical union execution with the plain one): BAD performance of 2.5 when sort occurs. FB 3.x better by  ~3 times
  • Check issues about fetches when insert data in child tables that violates FK constraint, 2.5 vs 3: same for both 2.5 and 3.0
  • Check again: how long DML can ignore request in MON$-table to be stopped (or disconnect attachment); too long wait when FB performs rollbacks after cancelling bulk DML, 2.5 vs 3.0: same for both 2.5 and 3.0
  • Compare index building time, table of 10E6 rows, 2.5 vs 3.0     3.0 loses!
  • Check select n01,count(*) cnt from tbig where n01 in(741,258,963) group by n01 for table tbig=10’000’000 rows (index on n01 present), increased page buffer up to maximum in 32bit: 128K pages, 2.5 vs 3.0: no changes in CPU time and statistics between 2.5 and 3.0
  • Compare performance of hash join (new in FB 3) vs merge join, table 3'000'000 rows, 2.5 vs 3.0: hash join LOSES, 20%
  • Check again Fb3 performance of hash join when buf=128K and FileSysThreshold=512K (TOO SLOW), (add gathering info from mon$io + mon$rec: too low values!): Bad performance! Values from mon$io and mon$rec almost not changed in time: fetched only 113'000 pages over 3 hours
  • Check whether Fb3 protection from big natural scans that forced out cached pages was really fixed: Yes, fixed.
  • firebird.conf parameter 'AuthClient' should be exactly as this: AuthClient =Legacy_Auth, Srp, Win_Sspi; removing Win_Scpi (i.e. AuthClient = Srp, Legacy_Auth) leads to blocking of trace start connecting from 2.5 to 3.0
  • Test performance of windowed functions: lead(. . .)over(order by <indexed_field>) in comparison with old style: select id_curr, (select first 1 id id_next from tr b where> order by id) from tr a order by id: Fb3 performs badly.  Also performs badly in comparison with Oracle 10/11.
  • Check CORE-3362 (cursor stability - integral ticket of samples)    
  • Check again new single sort when union hierarchy present, since 05-08-2013    
  • Check again merge when more than one rows in join cond: CORE-2274: NOT FIXED YET
  • Check again issues about visibility of data for two transactions in the same connect (using GTT on commit preserve rows): OK when TIL = read_only + read_committed
  • Check again issue about performance of RDB$GET_CONTEXT and RDB$SET_CONTEXT, 2.5 vs 3.0: 3.0 better
  • Check for regression: CORE-3650 (recreation of collation for utf8 from unicode with option 'NUMERIC-SORT=1' leads to FB death)    
  • Check for regression: CORE-3683 (Wrong results if the recursive query contains an embedded GROUP BY clause): OK (no regression)
  • Check performance of misc. mon$ queries, 2.5 vs 3.0: 3.0 same as 2.5 at time; since refactored now by dimitr, I believe
  • Check again performance of SIMILAR TO vs LIKE, 2.5 vs 3.0: both still VERY bad. Time for LIKE = 1, time for SIMILAR TO = 22
  • Check issue about cursor stability: OK in 3.0
  • Check ‘strange results’ of merge that were on 2.5: OK in 3.0
  • Check cursor stability sample: OK in 3.0
  • Performance test of new FB-3 features related to obtaining constant values in Fb 3 (sample from dimitr scalar functions)
  • Compare performance of "search holes in sequences", 2.5 vs 3.0: Fb 3.0 wins: 0.25 vs 7 in 2.5 (!)
  • Check performance of inserts 20’000 blobs vs varchars : same as in 2.5: (ins + commit) 16.65” + 10.05” for varchars vs 41.31” + 0.81” for blobs
  • Check again CORE-3340 (could insert duplicate in PK in autonom TX, leading to unrecoverable .fbk), 2.5 vs 3.0: OK on both FB 2.5 and 3.0
  • Check CORE-3977 (DELETE FROM MON$STATEMENTS does not interrupt a longish fetch in Fb 3.0: NOT yet solved on table with 10E9 rows.  Made a new test for this issue and opened a new tracker ticket (CORE-4179: mon$tables cannot be queried while a few ISQLs are doing bulk updates of huge table)
  • Get strange ability to create collation for WIN1251 from UNICODE case insensitive, which does not work properly (Fb 3 – see core-4180)
  • Invalid number of indexed pages in report of validation (hundred of trillions)
  • Run gbak –b t10e9 and found ZERO activity of FB
  • Check validation report about bad index pages numbers, Fb 3 on Linux: OK on snapshot LI-T3.0.0.30590    
  • Run again gbak –b t10e9, with logging via querying mon$-tables     .fdb page size=4K: trouble with reading $mon-tables
  • Test again case when few table records are stored in one database page
  • Test on connect + disconnect of hundred ISQL, inifinite times (purpose: check whether memory leak will be detected in such case). Using WI-T3.0.0.30590, SS, Fatal lock manager error: invalid lock id (nnnn), errno: 0; dumps of LT. MEMORY LEAK DETECTED
  • Test again bulk DML on table with 10E9 rows,new page size = 16K (Fb 3): Bulk updates causes FB perform very long rollbacks that continue even after db shutdown (have sample with 60 minutes!)
  • Fb3 can not correctly be stopped (via /etc/init.d/fb30xx stop) if it is doing rollbacks at that moment   
  • Implement and run test for watching Fb3 memory consumption when bulk connect/disconnect occurs
  • Continued investigation of test to compare on table 10E9: creation of two indexes "in parallel" vs sequential and comparing "pseudo-parallel" indexes for the same table
  • Finished investigation of Fb3 crashing when bulk ISQLs are killed from database with locked record in some table (CORE-4185)
  • Check again CORE-4036 (Bugcheck or database corruption under Fb3 when attempting to store long incompressible data into a table): Ok (no error)
  • Test issue from doc/readme.transactions: no auto undo when doing bulk UPDATES (rather than inserts)
  • Check slow QUIT after update 400,000 rows and rollback: more than 20 seconds
  • Check test of FB crash on SuperClassic, seems to be linked to CORE-4185 (discuss with Alex)
  • Rebuild Fb3 with patch from Alex (lck.cpp), retry test on bulk connect/disconnect isqls: OK, no more crashes
  • Run several tests from Russian forum concerning CORE-4194 and other reports that infinite ES EDS with AUTONOMOUS transaction leads to memory leak and error 335544333: internal consistency check (cannot start cache writer thread)) in Fb 3

  • Repeated testing of bulk connects/disconnects on successive Fb 2.5.3 builds
  • Repeated testing related to CORE-4185 crash scenario on successive Fb 2.5.3 builds/patches, in concert with Alex
  • Fixed error in 2.5.3 and 3.0 that led FB 2.5.3 to crash (CORE-4211)
  • Investigation of server crashes when attempting to trace activity on a database having a db-level trigger
  • Adapt and run test for connect establishing speed to FB 3.0 vs FB 2.5, buffers=65000 in both instances (CORE-4225     4)
  • Discussion with Alex and implementation of improvements for connect calibration test
  • Run test with for connect speed calibration with applying dumpTimer.patch (from Alex), get stacktraces, LT snapshots at the
  • moments when connect was more 4 seconds. Sent them to Alex along with core dumps.    
  • Run multiple variants of test on huge table (10E9 rows) under Fb 3 retesting issues from CORE-4179: querying mon$-tables after forced shutdown database now faster.
  • Run test: gfix –shut full when bulk DMLs working. Check whether gfix is still async even when FW = ON: Hooray! gfix -shut now becomes SYNCHRONOUS and does not return to command prompt untill all rollbacks of DML are done.
  • Rerun IDX_UNDER_LOAD test with client 3.0, default firebird.conf and without calibration test (300 connects) – Alex’s suggestion for addressing the slow connect problem also seen in 2.5
  • Multiple rebuilds of Fb3 and runs with gdb to get stack traces for server hangs (perhaps from querying mon$-tables) and discussion about this with Alex and Vlad. All test cases have been sent to Vlad. No solution yet.

Pavel Zotov
Moscow, Russian Federation
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