fix(openreader): Use READ COMMITTED to allow the usage of PostgreSQL replicas#449
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HRGCompany wants to merge 2 commits intosubsquid:masterfrom
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fix(openreader): Use READ COMMITTED to allow the usage of PostgreSQL replicas#449HRGCompany wants to merge 2 commits intosubsquid:masterfrom
HRGCompany wants to merge 2 commits intosubsquid:masterfrom
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…replicas SERIALIZABLE isolation is incompatible with PostgreSQL replicas, causing "cannot use serializable mode on a hot standby" errors when OpenReader is pointed at a read-only replica. Since OpenReader only performs read queries, READ COMMITTED is sufficient and works correctly on both primary and replica servers. This allows distributing requests across replicas for read-only queries, while keeping indexers pointing toward the primary server to avoid any overload.
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Pull request overview
Updates OpenReader’s transaction isolation level to be compatible with PostgreSQL read-only replicas (hot standby), avoiding cannot use serializable mode on a hot standby errors while keeping queries read-only.
Changes:
- Change OpenReader’s
START TRANSACTIONisolation level fromSERIALIZABLEtoREAD COMMITTEDfor read-only transactions.
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Contributor
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Hey, sorry for the long time reply. Could you please implement it as a configurable option, so It coiuld be passed to the server via command options? |
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SERIALIZABLE isolation is incompatible with PostgreSQL replicas, causing "cannot use serializable mode on a hot standby" errors when OpenReader is pointed at a read-only replica.
Since OpenReader only performs read queries, READ COMMITTED is sufficient and works correctly on both primary and replica servers.
This allows distributing requests across replicas for read-only queries, while keeping indexers / processors pointing toward the primary server to avoid any overload.