Sql – Copy a table (including indexes) in postgres

indexingpostgresqlsql

I have a postgres table. I need to delete some data from it. I was going to create a temporary table, copy the data in, recreate the indexes and the delete the rows I need. I can't delete data from the original table, because this original table is the source of data. In one case I need to get some results that depends on deleting X, in another case, I'll need to delete Y. So I need all the original data to always be around and available.

However it seems a bit silly to recreate the table and copy it again and recreate the indexes. Is there anyway in postgres to tell it "I want a complete separate copy of this table, including structure, data and indexes"?

Unfortunately PostgreSQL does not have a "CREATE TABLE .. LIKE X INCLUDING INDEXES'

Best Solution

New PostgreSQL ( since 8.3 according to docs ) can use "INCLUDING INDEXES":

# select version();
                                             version
-------------------------------------------------------------------------------------------------
 PostgreSQL 8.3.7 on x86_64-pc-linux-gnu, compiled by GCC cc (GCC) 4.2.4 (Ubuntu 4.2.4-1ubuntu3)
(1 row)

As you can see I'm testing on 8.3.

Now, let's create table:

# create table x1 (id serial primary key, x text unique);
NOTICE:  CREATE TABLE will create implicit sequence "x1_id_seq" for serial column "x1.id"
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "x1_pkey" for table "x1"
NOTICE:  CREATE TABLE / UNIQUE will create implicit index "x1_x_key" for table "x1"
CREATE TABLE

And see how it looks:

# \d x1
                         Table "public.x1"
 Column |  Type   |                    Modifiers
--------+---------+-------------------------------------------------
 id     | integer | not null default nextval('x1_id_seq'::regclass)
 x      | text    |
Indexes:
    "x1_pkey" PRIMARY KEY, btree (id)
    "x1_x_key" UNIQUE, btree (x)

Now we can copy the structure:

# create table x2 ( like x1 INCLUDING DEFAULTS INCLUDING CONSTRAINTS INCLUDING INDEXES );
NOTICE:  CREATE TABLE / PRIMARY KEY will create implicit index "x2_pkey" for table "x2"
NOTICE:  CREATE TABLE / UNIQUE will create implicit index "x2_x_key" for table "x2"
CREATE TABLE

And check the structure:

# \d x2
                         Table "public.x2"
 Column |  Type   |                    Modifiers
--------+---------+-------------------------------------------------
 id     | integer | not null default nextval('x1_id_seq'::regclass)
 x      | text    |
Indexes:
    "x2_pkey" PRIMARY KEY, btree (id)
    "x2_x_key" UNIQUE, btree (x)

If you are using PostgreSQL pre-8.3, you can simply use pg_dump with option "-t" to specify 1 table, change table name in dump, and load it again:

=> pg_dump -t x2 | sed 's/x2/x3/g' | psql
SET
SET
SET
SET
SET
SET
SET
SET
CREATE TABLE
ALTER TABLE
ALTER TABLE
ALTER TABLE

And now the table is:

# \d x3
                         Table "public.x3"
 Column |  Type   |                    Modifiers
--------+---------+-------------------------------------------------
 id     | integer | not null default nextval('x1_id_seq'::regclass)
 x      | text    |
Indexes:
    "x3_pkey" PRIMARY KEY, btree (id)
    "x3_x_key" UNIQUE, btree (x)