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jkaczman merged 2 commits into from
Sep 16, 2026
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Docs for https://github.com/pgdogdev/pgdog/pull/1541 #114

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8d7af97
Docs for https://github.com/pgdogdev/pgdog/pull/1541
jkaczman Sep 15, 2026
8706997
Helm typo
jkaczman Sep 15, 2026
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4 changes: 4 additions & 0 deletions docs/configuration/pgdog.toml/rewrite.md
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Original file line number Diff line number Diff line change
Expand Up @@ -13,6 +13,7 @@ The `rewrite` section controls PgDog's automatic SQL rewrites for sharded databa
shard_key = "error"
split_inserts = "error"
primary_key = "ignore"
omni_non_deterministic_functions = "ignore"
```
=== "Helm chart"
```yaml
Expand All @@ -21,6 +22,7 @@ The `rewrite` section controls PgDog's automatic SQL rewrites for sharded databa
shardKey: "error"
splitInserts: "error"
primaryKey: "ignore"
omniNonDeterministicFunctions: "ignore"
```

| Setting | Description | Default |
Expand All @@ -29,6 +31,7 @@ The `rewrite` section controls PgDog's automatic SQL rewrites for sharded databa
| `shard_key` | Behavior when an `UPDATE` changes a sharding key: `error` rejects the statement,<br>`rewrite` migrates the row between shards,<br>`ignore` forwards it unchanged. | `"error"` |
| `split_inserts` | Behavior when a sharded table receives a multi-row `INSERT`: `error` rejects the statement, `rewrite` fans the rows out to their shards, `ignore` forwards it unchanged. | `"error"` |
| `primary_key` | Behavior when an `INSERT` is missing a `BIGINT` primary key: `error` rejects the statement,<br>`rewrite` auto-injects `pgdog.unique_id()` for missing keys,<br>`ignore` allows the INSERT without modification. | `"ignore"` |
| `omni_non_deterministic_functions` | Behavior when an `INSERT` is headed to an omnisharded table using a function (such as date-time functions) that will not be consistent when performing the functions separately on each shard. Thus, it re-writes all such functions before performing the `INSERT` with constant values to maintain consistency. Example: `NOW()` is re-written to `2026-09-15 18:14:09.123456-05` (or whatever the current time is) before performing the individual `INSERT` operations. This applies to both `DEFAULT` table schema and functions called within a VALUES list of an `INSERT`. `ignore` allows the `INSERT` without modification. | `"ignore"` |

!!! note "Two-phase commit"
Consider enabling [two-phase commit](../../features/sharding/2pc/index.md) when either feature is set to `rewrite`. Without it, rewrites are committed shard-by-shard and can leave partial changes if a transaction fails.
Expand All @@ -41,6 +44,7 @@ The admin database exposes these toggles via the `SET` command:
SET rewrite_enabled TO true; -- enable/disable rewrite engine
SET rewrite_shard_key_updates TO rewrite; -- error | rewrite | ignore
SET rewrite_split_inserts TO rewrite; -- error | rewrite | ignore
SET rewrite_omni_non_deterministic_functions TO rewrite; -- error | rewrite | ignore
```

The setting changes are applied immediately. These overrides allow canary testing before persisting them in `pgdog.toml`.
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