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* Timestamp index not used
@ 2003-05-08 03:56 david@stanaway.net
2003-05-08 05:26 ` Re: Timestamp index not used Tom Lane <tgl@sss.pgh.pa.us>
0 siblings, 1 reply; 2+ messages in thread
From: david@stanaway.net @ 2003-05-08 03:56 UTC (permalink / raw)
To: pgsql-sql
What kind of index should I be using on the timestamp column for it to
be used for BETWEEN and > operations?
radius=# EXPLAIN SELECT * from alldata where loggedat > '2003-05-07';
NOTICE: QUERY PLAN:
Seq Scan on alldata (cost=0.00..286136.26 rows=1428487 width=780)
EXPLAIN
radius=# \d alldata
Table "alldata"
Column | Type |
Modifiers
-----------------------+--------------------------+----------------------------------------------------
query | text |
cisco_nas_port | text |
h323_remote_address | text |
h323_conf_id | text |
h323_setup_time | text |
h323_call_origin | text |
h323_call_type | text |
h323_connect_time | text |
h323_disconnect_time | text |
h323_disconnect_cause | text |
h323_voice_quality | text |
h323_gw_id | text |
nas_ip_address | text |
nas_port_type | text |
called_station_id | text |
calling_station_id | text |
acct_status_type | text |
acct_session_id | text |
acct_input_octets | text |
acct_output_octets | text |
acct_input_packets | text |
acct_output_packets | text |
acct_session_time | text |
acct_delay_time | text |
identity | integer | default
nextval('alldata_identity_seq'::text)
loggedat | timestamp with time zone | default
('now'::text)::timestamp(6) with time zone
Indexes: alldata_call_origin_idx,
alldata_call_type_idx,
alldata_conf_id_idx,
alldata_nas_ip_address_idx,
alldate_loggedat_idx,
remote_address_idx
Unique keys: alldata_identity_pkey
radius=# \d alldate_loggedat_idx
Index "alldate_loggedat_idx"
Column | Type
----------+--------------------------
loggedat | timestamp with time zone
btree
^ permalink raw reply [nested|flat] 2+ messages in thread
* Re: Timestamp index not used
2003-05-08 03:56 Timestamp index not used david@stanaway.net
@ 2003-05-08 05:26 ` Tom Lane <tgl@sss.pgh.pa.us>
0 siblings, 0 replies; 2+ messages in thread
From: Tom Lane @ 2003-05-08 05:26 UTC (permalink / raw)
To: david@stanaway.net; +Cc: pgsql-sql
<david@stanaway.net> writes:
> radius=# EXPLAIN SELECT * from alldata where loggedat > '2003-05-07';
> NOTICE: QUERY PLAN:
> Seq Scan on alldata (cost=0.00..286136.26 rows=1428487 width=780)
^^^^^^^^^^^^
The planner seems to think that this query will return rather a lot of
rows ... which would imply that a seqscan isn't necessarily a bad idea.
Is that rows estimate accurate? (If not, have you ANALYZEd this table
lately?)
regards, tom lane
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2003-05-08 03:56 Timestamp index not used david@stanaway.net
2003-05-08 05:26 ` Tom Lane <tgl@sss.pgh.pa.us>
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