jit_above_cost, jit_inline_above_cost, and jit_optimize_above_cost
PostgreSQL's JIT compiler fires based on estimated query cost, but that estimate measures data volume, not expression complexity.
jit_expressions and jit_tuple_deforming
PostgreSQL's JIT compiler has two jobs: compiling expressions and deforming tuples. Here's how to isolate JIT bugs with two simple boolean toggles.
jit and jit_provider
PostgreSQL's JIT compiler trades upfront compilation time for faster query execution—but it silently does nothing if the LLVM library isn't installed.
io_method and io_workers
Choose your I/O execution engine with `io_method` and size the worker pool with `io_workers`—and yes, you can resize workers without restarting.
io_max_concurrency
PostgreSQL 18's new io_max_concurrency caps per-process I/O operations in flight.
io_combine_limit and io_max_combine_limit
PostgreSQL 17 introduced read streams that combine adjacent disk blocks into larger I/O requests.
IntervalStyle
IntervalStyle changes how PostgreSQL parses interval input, not just formats output—and in one case, it silently flips the sign of your data.
integer_datetimes
Every PostgreSQL connection since 8.0 has heard the server announce `integer_datetimes`—a parameter that's had only one possible value since PostgreSQL 10.
in_hot_standby
Discover how `in_hot_standby` lets clients automatically detect whether they're connected to a primary or standby—and why the timing of that notification…
ignore_system_indexes
Recover from catalog index corruption by sequentially scanning system tables instead of using indexes.