Re: [sqlite] All versions compatible "very big" estimatedCost (Virtual tables)

2017-04-04 Thread Max Vlasov
On Tue, Mar 28, 2017 at 11:26 AM, Max Vlasov wrote: > > > So, what is the maximum reasonable value of estimatedCost that will not > turn sqlite into possible overflow errors while telling at the same time > that I consider some variant very, very expensive? Or maybe changing cheap > from 1 to 0 w

Re: [sqlite] All versions compatible "very big" estimatedCost (Virtual tables)

2017-03-28 Thread Hick Gunter
] Im Auftrag von Max Vlasov Gesendet: Dienstag, 28. März 2017 13:37 An: SQLite mailing list Betreff: Re: [sqlite] All versions compatible "very big" estimatedCost (Virtual tables) On Tue, Mar 28, 2017 at 12:51 PM, Dominique Devienne wrote: > On Tue, Mar 28, 2017 at 11:00 AM, Hick

Re: [sqlite] All versions compatible "very big" estimatedCost (Virtual tables)

2017-03-28 Thread Max Vlasov
On Tue, Mar 28, 2017 at 12:51 PM, Dominique Devienne wrote: > On Tue, Mar 28, 2017 at 11:00 AM, Hick Gunter wrote: > > > > > The "estimated cost" is described as "how many disk IO operations are > > expected". Version higher than 3.8.2 allow setting an "estimatedRows" > > (default: 25) and versi

Re: [sqlite] All versions compatible "very big" estimatedCost (Virtual tables)

2017-03-28 Thread Dominique Devienne
On Tue, Mar 28, 2017 at 11:00 AM, Hick Gunter wrote: > >FWIW, I've often wondered about the cost estimates of real tables versus > virtual tables, especially since many vtables implementations don't involve > real IO but pure in-memory computations. There's >very little advice or > documentation

Re: [sqlite] All versions compatible "very big" estimatedCost (Virtual tables)

2017-03-28 Thread Hick Gunter
>FWIW, I've often wondered about the cost estimates of real tables versus >virtual tables, especially since many vtables implementations don't involve >real IO but pure in-memory computations. There's >very little advice or >documentation on this important subject, and Max's email reveals that

Re: [sqlite] All versions compatible "very big" estimatedCost (Virtual tables)

2017-03-28 Thread Dominique Devienne
On Tue, Mar 28, 2017 at 10:26 AM, Max Vlasov wrote: > I sometimes use virtual tables to implement some kind of one-to-many > output. One of examples mentioned previously was the comma list virtual > table when a field containing comma-separated values might be used to > output rows of values from

[sqlite] All versions compatible "very big" estimatedCost (Virtual tables)

2017-03-28 Thread Max Vlasov
Hi, I sometimes use virtual tables to implement some kind of one-to-many output. One of examples mentioned previously was the comma list virtual table when a field containing comma-separated values might be used to output rows of values from this list. Other example - performing regexp-like query