Thanks! I'm happy to help. ________________________________ From: alex xmb sw ratchev <fxmb...@gmail.com> Sent: Friday, February 9, 2024 9:13 PM To: Chester Ramey <chet.ra...@case.edu> Cc: Casey Johnson <stry...@hotmail.com>; bug-bash <bug-bash@gnu.org> Subject: Re: Slow history load with some values of HISTSIZE
On Sat, Feb 10, 2024, 03:06 Chet Ramey <chet.ra...@case.edu<mailto:chet.ra...@case.edu>> wrote: On 2/3/24 3:29 PM, Casey Johnson wrote: > Bash Version: 5.1 > Patch Level: 16 > Release Status: release > > Description: > > The current implementation of the command history takes a long time to load > a large HISTFILE when history is stifled. This is because there is a > memmove() for every line of HISTFILE once HISTSIZE lines have been loaded. > If N is the number of lines in HISTFILE then the cost of the memmoves ends > up being something like (N - HISTSIZE) * HISTSIZE, peaking when HISTSIZE is > roughly N/2. Thanks for the report and the patch. I applied it with some tweaks and saw a dramatic performance improvement for very large history files (I tested with one that was about 690000 entries) where HISTSIZE is significantly smaller (I tested with HISTSIZE=100000): from around 11 seconds to less than 0.3 seconds. ++ speed optimization greets ++ Chet -- ``The lyf so short, the craft so long to lerne.'' - Chaucer ``Ars longa, vita brevis'' - Hippocrates Chet Ramey, UTech, CWRU c...@case.edu<mailto:c...@case.edu> http://tiswww.cwru.edu/~chet/
