farrokhi/pg_repack
1
0
Fork 0
Code Issues Pull Requests Releases Wiki Activity

Some further fixes/cleanup/wordsmithing of the doc changes.

Browse Source
This commit is contained in:
Josh Kupershmidt 2015-05-19 20:10:25 -04:00
parent c375c2009d
commit 8fe2cf1296
1 changed files with 21 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

39
doc/pg_repack.rst
View File

@ -429,31 +429,34 @@ earlier versions which could result in data corruption.
Details
-------
Full table repack
^^^^^^^^^^^^^^^^^
Full Table Repacks
^^^^^^^^^^^^^^^^^^
To perform a full table repack, pg_repack will:
To perform a full-table repack, pg_repack will:
* create a log table
* create a trigger on the old table to log all changes to the log table
* create a new table containing all data in the old table
* create all indexes on the new table
* apply all changes from the log table to the new table
* when the log table is empty, swap the table in the system catalog
* drop the old table
1. create a log table to record changes made to the original table
2. add a trigger onto the original table, logging INSERTs, UPDATEs and DELETEs into our log table
3. create a new table containing all the rows in the old table
4. build indexes on this new table
5. apply all changes which have accrued in the log table to the new table
6. swap the tables, including indexes and toast tables, using the system catalogs
7. drop the original table
pg_repack will only acquire ACCESS EXCLUSIVE locks when creating the trigger and when
switching the table files, all other operations are lock-free on the source table.
pg_repack will only hold an ACCESS EXCLUSIVE lock for a short period during
initial setup (steps 1 and 2 above) and during the final swap-and-drop phase
(steps 6 and 7). For the rest of its time, pg_repack only needs
to hold an ACCESS SHARE lock on the original table, meaning INSERTs, UPDATEs,
and DELETEs may proceed as usual.
Index only repack
^^^^^^^^^^^^^^^^^
Index Only Repacks
^^^^^^^^^^^^^^^^^^
To perform a index only repack, pg_repack will:
To perform an index-only repack, pg_repack will:
* create a new index on the table using CONCURRENTLY
* swap the index in the catalog
* drop the old index
1. create new indexes on the table using CONCURRENTLY matching the definitions of the old indexes
2. swap out the old for the new indexes in the catalogs
3. drop the old indexes
Creating indexes concurrently comes with a few caveats, please see `the documentation`__ for details.