tree 5792c18ce8bf3fe44f3f510d783a8aa4c6623787
parent 8bb9b1dcf341c155741dfe53ed6dc7b6e6b73d4b
author Jacek Centkowski <jcentkowski@collab.net> 1523883538 +0200
committer Jacek Centkowski <jcentkowski@collab.net> 1524559041 +0200

Introduce lib that contains Postgres based persistent cache impl

The following change introduces cache-postgres.jar library that contains
Postgres based persistence implementation for Gerrit caches.

It is heavily based on existing Gerrit's H2CacheImpl and could/should
be further optimized in the follow up changes.

One builds it by calling:
bazel build cache-postgres

Installation:
1. create Postgres DB e.g. gerrit_caches
2. copy 'bazel-genfiles/cache-postgres.jar' to GERRIT_SITE/lib dir
3. modify GERRIT_SITE/etc/gerrit.config with the following changes
  a) inform Gerrit that main library's module should be loaded
    gerrit.installModule
"com.googlesource.gerrit.modules.cache.pg.CacheModule"

  b) specify connection to Postgres DB
    cache.url
"jdbc:postgresql://localhost:5432/gerrit_caches?user=gerrit&password=gerrit"
4. restart Gerrit
5. remaining configuration parameters are mentioned in README.md

NOTES:
1. current implementation doesn't contain migration step and
existing data will be wiped out.
2. it uses INSERT INTO ... ON CONFLICT DO UPDATE ... upsert syntax [1]
therefore it is Postgres 9.5+ compatible.

[1] https://stackoverflow.com/questions/17267417/how-to-upsert-merge-insert-on-duplicate-update-in-postgresql

Depends-On: I7562b210fad4c5f6dc67887f627cf76815a378cb
Change-Id: I33fa1cd3dba1c1b246aecaa05a052f7348ddd64a
Signed-off-by: Jacek Centkowski <jcentkowski@collab.net>