> On 11 Jul 2022, at 10:16 AM, Raj kumar <rajkumar820999@xxxxxxxxx> wrote: > > Hi, > > How can I improve "select count(*)" for larger tables? I'm doing a db migration and need to validate the data count. > "select count(*) " queries are taking more than 30 minutes for some tables which is more than the downtime we have. > Will work_mem increase help? or how can i speed up this row count? Personally, whenever I’ve had slow count(*) or count (distinct id), eventually I’ve resorted to Unix tools. psql “select id from my_table" | sort -u | wc -l The convenience/performance tradeoff depends heavily on your schema. After all unix streams don’t know much about your integrity requirements. > > Thanks, > Raj
