First release: a DBI backend for Trino over the cluster's HTTP REST API.
Trino(), dbConnect(), dbDisconnect() and dbIsValid() manage a
connection's life cycle. dbConnect() probes /v1/info, so a wrong address
or a rejected credential fails at connection time. Its arguments are
validated before the coordinator is contacted, with plain messages.trino_auth_basic(), trino_auth_jwt() and trino_auth_oauth2() supply
credentials, and trino_ssl() sets the TLS options, including ca_bundle
to trust an internal certificate authority without turning verification off.
dbConnect() refuses to send credentials to an http:// host unless
allow_http_auth = TRUE.timeout bounds each HTTP request (60 seconds by default) and
query_max_run_time bounds a query on the cluster.dbSendQuery(), dbFetch(), dbGetQuery(), dbExecute(),
dbSendStatement(), dbHasCompleted() and dbClearResult() run queries,
with automatic nextUri pagination, chunked fetching through
dbFetch(n = ), and server-side cancellation when a running result is
cleared.dbExecute() returns the number of rows Trino says a statement changed, and
0 for DDL. dbSendStatement() runs the statement to completion, so that
dbGetRowsAffected() answers straight away.dbColumnInfo() and dbFetch(n = 0) describe the columns before the first
row is fetched.dbIsValid() on a result reports whether it has been cleared, not whether
the query has finished, as DBI requires: dbColumnInfo() and
dbGetRowCount() keep working until dbClearResult(). dbHasCompleted()
reports that every row has been consumed.trino_query_error and
trino_canceled, carrying the server's error_name, error_code,
error_type and query_id, so a caller can react to a specific Trino error
without matching on the message text.params is an error, and dbBind() says that parameters are not
supported. Put values into a statement with DBI::sqlInterpolate() or
glue::glue_sql(): dbQuoteLiteral() writes typed Trino literals
(DATE '...', TIMESTAMP '...', TRUE, doubles that read back exactly).BIGINT is returned as exact bit64::integer64 by default
(bigint = "numeric" or "character" for the alternatives), and DOUBLE
bit for bit. Trino sends both as JSON numbers, which are converted without
going through text. The lowest BIGINT, which bit64 keeps for NA, is NA
with a warning.TIMESTAMP WITH TIME ZONE is
resolved per value whether the server sends a zone name or an offset.INTERVAL
columns are read as text, and a bare NULL as a logical.dbDataType() and trino_type_to_r() map between R and Trino types.dbListTables(), dbExistsTable(), dbListFields() and dbGetInfo() read
the catalog. Table names are strings of one to three parts, DBI::Id() or
quoted identifiers, and are matched ignoring case, as Trino does.
dbExistsTable() counts a row in information_schema.tables, so its cost
does not grow with the size of the schema, and reports FALSE rather than an
error for a name in a catalog that does not exist.dbWriteTable(), dbAppendTable() and dbCreateTable() write data frames.
Rows go in as INSERT INTO ... VALUES statements of chunk_size rows each
(1000 by default), every value a literal, since Trino's protocol has no
parameter binding. dbWriteTable(overwrite = TRUE) renames the existing
table rather than dropping it, and restores it if the write fails.
dbRemoveTable() and dbRenameTable() drop and rename tables, and
temporary = TRUE is an error, because Trino has no temporary tables.dbBegin(), dbCommit(), dbRollback() and dbWithTransaction() run
statements inside a Trino transaction. Whether a ROLLBACK undoes a write
depends on the connector behind the catalog; dbBegin() warns for the
catalogs that hold no real storage (memory, system, tpch, tpcds,
jmx and blackhole).dplyr pipelines are translated to Trino SQL through a dbplyr dialect,
which requires dbplyr >= 2.6.0. The methods are registered when dbplyr is
loaded rather than through NAMESPACE, because a NAMESPACE directive for
sql_dialect(), which older versions lack, would make such a dbplyr fail to
load./ divides as a double, %% takes the sign of the divisor,
as.integer() and as.integer64() truncate, grepl(), sub() and
gsub() honour fixed and ignore.case and accept R's \\1
back-references, and paste(), paste0() and str_c() accept columns of
any type. days(), weeks(), months(), years(), hours(), minutes()
and seconds() build intervals, for date + days(1). A Date or POSIXct
from R becomes a typed literal in a pipeline.filter_out(), from dplyr 1.2.0, uses Trino's native IS DISTINCT FROM
rather than the CASE WHEN comparison dbplyr falls back to. dplyr 1.2.0's
when_any()/when_all() and recode_values()/replace_values()/
replace_when() are not translated, because dbplyr 2.6.0 has no translation
for them on any backend.copy_to() and compute() write through dbWriteTable(), and need
temporary = FALSE and a table name. compute() does not run ANALYZE,
which not every connector supports.WHERE 0 = 1) rather than
LIMIT 0. Both plan without reading data on Trino, and the default avoids
depending on dbplyr internals.simulate_trino() returns a connection that carries the dialect without a
session, for inspecting translated SQL with no cluster to hand.round() on halves, the approximate median() and quantile(), DECIMAL
beyond 15 digits, and paste() of a DOUBLE.dev/record-fixtures.R), so everything
about how values are encoded is tested against payloads a cluster really
sends.tests/testthat/test-live.R runs against a real Trino when
RTRINO_TEST_URL is set, and CI runs it against trinodb/trino.