performance issue with gnumeric-LONG - stalls near crash
the sheets in the attached file show a mysterious performance degradation with gnumeric-long versions,
mysterious_slowdowns_10.gnumeric
I. normal copy is ok, for recheck: 'select all ( ctrl-A ) - copy ( ctrl-C ) - new file ( ctrl-N ) - paste ( ctrl-V )', finishes in seconds,
II. after deleting the grey block at the bottom of the tables ( e.g. C884:D885 on Sheet1 ) already 'select all' becomes significantly slow,
doesn't matter if delete block ( ctrl-- ), delete content ( del ) or delete rows,
III. increasing from sheet to sheet with the length of the table, user experience for sheets 5 and 6 is 'final stall', that's where I started investigating,
IV. IMHO not justified as with the grey block the performance is better / normal,
as far as tested:
the problem is stable against file save and re-appears in a re-opened file,
it doesn't show up in gnumeric-double versions,
the issue is 'sheet dependent' / 'sheet-locale',
( it's possible to have multiple sheets in one workbook from which those subject to deletion fail while others keep working well )
same problem with 'power( 10, cell-left ),
having the weak situation also other actions, e.g selecting blocks from the table, tend to stall,
tested with various flavours of gnumeric 1.12.54-long.
The sheets in themself are no longer particularly meaningful, they are reduced from a bigger context to isolate and demonstrate the problem.
with some effort it's possible to construct sheets with other operations having similar weakness, see sheet7.