On Tue, May 3, 2016 at 1:35 PM, Maxim Boguk <maxim.boguk@xxxxxxxxx> wrote:
On Tue, May 3, 2016 at 8:09 PM, Maxim Boguk <maxim.boguk@xxxxxxxxx> wrote:Hi,I started with empty table with index over
custom_fields | jsonbfielddefined as:
"idx_learners_custom_fields" gin (custom_fields)Globally gin_pending_list_limit set to 2MB.Database version is 9.5.2.Now question:
If table populated with 1M records in single transaction then the final size of the GIN index is:
4265 MBbut after I performed reindex index idx_learners_custom_fields;the index size had been reduced 15x to 295 MB.Is this behavior expected?It's look easy to reproduce.
I can send a sample dataset for analyze.
sample data are always welcome !
drop table if exists test;
create table test (custom_fields jsonb);
create index test_gin_key on test USING GIN(custom_fields);
insert into test select custom_fields from public.learners;
INSERT 0 1000000
\di+ test_gin_key
List of relations
Schema | Name | Type | Owner | Table | Size | Description
--------+--------------+-------+----------+-------+---------+-------------
public | test_gin_key | index | postgres | test | 4211 MB |
reindex index test_gin_key;
\di+ test_gin_key
List of relations
Schema | Name | Type | Owner | Table | Size | Description
--------+--------------+-------+----------+-------+--------+-------------
public | test_gin_key | index | postgres | test | 295 MB |
--Maxim Boguk
Senior Postgresql DBA
http://www.postgresql-consulting.com/
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