crontab ubuntu

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docker

start downloaded container: docker start hash or name from docker ps -a docker build ./ -t findli/ubuntu_base:18_03_2023 ************ docker-compose:     build:       context: ./frontend - контекст это директория в которой будет искаться dockerfile       dockerfile: Dockerfile равнозначно:     build:       #context: ./frontend       dockerfile: frontend/Dockerfile ************ ************ ********** error:  when docker-compose up --force-recreate --build --remove-orphans langapp-back strconv.Atoi: parsing "": invalid syntax to fix: comment existing containers in docker-compose.yaml file. replace them by something else. then docker compose up --remove-orphans then revert suspicious containers in docker-conpose file then docker compose up will work. src: https://github.com/docker/compose-cli/issues/1537#issuecomment-1284828193  ********** ********** https://stackoverflow.com/a/52...
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unix linux usefull commands; clear up disk space

df -h ncdu - check directory sizes ss -plunt for app and port list  clear log:  rm /var/log/btmp.* journalctl --disk-usage journalctl --vacuum-size=50M journalctl --verify nano /etc/systemd/journald.conf SystemMaxUse=50M SystemMaxFileSize=12M systemctl restart systemd-journald nano /etc/logrotate.conf daily rotate 1 https://unix.stackexchange.com/a/605809/346938 https://www.linuxuprising.com/2019/04/how-to-remove-old-snap-versions-to-free.html
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sql optimizations

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B-tree is a self-balancing tree that maintains sorted data and allows operation in logarithmic time. B-trees can handle range queries on sorted data (<, ≤, >, ≥, between, in, is null, is not null) B-tree index can also be used for queries that involve pattern matching operator LIKE or ~ if the pattern is a constant and the anchor is at the beginning of the pattern. For example, you can try matching queries column_name LIKE ‘Apple%’ or column_name ~ ‘^Apple’ But, querying ‘%macbook%’ or ‘%pro’ will not be efficient. For such queries, the query planner will resort to full-text sequential search which is not optimized. Enter, GIN indexes. GIN stands for Generalized Inverted Indexes. We can create a GIN index to speed up text searches: CREATE INDEX index_name ON table USING GIN (to_tsvector(‘english’, column_name)); The query above specifies that the English configuration can be used to parse and normalize the strings. And for the part of searching, a simple query to print the tit...
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