How to disable JIT statistics

Answer

JIT statistics could be effected by below parameters:

You can enable/disable below parameters in session or global level.
If you want to enable these parameters in session level you can enable with set command:
For example, NZSQL> SET ENABLE_JIT_DISPERSION=TRUE;
Or if you want to enable these parameters in global level, you can edit /nz/data/postgresql.conf file and restart Netezza.
For example, ENABLE_JIT_DISPERSION=1


1. DISPERSIONS

ENABLE_JIT_DISPERSION:
- enable the JIT statistics for getting dispersion information.
JIT_DISP_MIN_ROWS:
- A table with more records than the value of JIT_DISP_MIN_ROWS will try JIT statistics for getting dispersion information.
- There need JOINs between tables.

In this case, user can disable JIT Dispersion by disabling ENABLE_JIT_DISPERSION or specifying high value for JIT_DISP_MIN_ROWS, that is, more than the record count of the table.

2. OTHER STATISTICS (SUM, MAX, MIN, ...)
ENABLE_JIT_STATS:
- enable the JIT statistics for getting statistic information (SUM, MAX, ...)
JIT_STATS_MIN_ROWS:
- A table with more records than the value of JIT_STATS_MIN_ROWS will try JIT statistics for getting SUM, MAX,...
- The table's predicate should be located in FROM clause or WHERE clause.

In this case, user can disable JIT Stats by disabling ENABLE_JIT_STATS or specifying high value for JIT_STATS_MIN_ROWS.