Hi,
I understand that in READ COMMITTED isolation level, SELECT queries
reads a snapshot of the database as of the instant the query begins.
And also a concurrent transaction(uncommitted) writing to the same
table won't block the readers.
However, I see that in the heap_update(heapam.c) function there is a
brief interval(Lock and unlock the buffer) where a writer may block
readers if the writer is updating the same row which readers are
reading.
Could anyone please help me with the below query?
1) Is my understanding correct? In so, Is it not against the
statements "readers does not block writers and writers does not block
readers"
Best,
Ajay
